Intermittent Fasting Archives - Health Tips From The Professor

Is Time-Restricted Eating Better Than Other Diets?

October 10, 2023 by Dr. Steve Chaney

Is Time-Restricted Eating Right For You?

Author: Dr. Stephen Chaney

Time-restricted eating is the latest fad. If you read Dr. Strangeloves’ blogs, he or she will tell you that eating for 8-10 hours and fasting the rest of the day will change your metabolism. They tell you that:

You don’t need to change what you eat.
You don’t have to restrict calories.
You don’t have to restrict fats or carbs.
You will feel fuller and naturally eat less.
The pounds will just drop away magically.

And you will have benefits like:

Better blood sugar control.
Lower levels of heart-unhealthy lipids like LDL and triglycerides.
Enhanced cellular repair, which might help you live longer.

Are these claims true? Is there something special about time-restricted eating, or is it simply another way to cut calories?

Two recent studies (EA Thomas et al, Obesity; 30: 1027-1038, 2022) and (D Liu et al, New England Journal of Medicine, 386: 1495-1505, 2023) answered these questions by cutting calories to the same extent for people following a time-restricted eating pattern and people who had no restrictions on when they ate.

How Were These Studies Done?

Study 1: The authors enrolled 81 adults aged 18 to 50 years (average = 38 years, 69% female) with BMIs of 27 to 45 (overweight to morbidly obese).

The study lasted 39 weeks with measurements taken at baseline, 12 weeks, and 39 weeks.

The participants were divided into two groups:

A time-restricted eating group that was advised to restrict their eating to start eating within 3 hours of waking and restrict their eating to 10 hours.

A calorie restricted group that was given no time limitations on when they could eat.

Both groups were:

given a personalized calorie goal which represented a 35% caloric restriction based on measurements of their resting energy expenditure.

enrolled in a 39-week, group-based, comprehensive weight-loss program. Groups were taught by registered dietitians and met weekly through the first 12 weeks, and monthly between weeks 13 and 39.

Study 2: The authors enrolled 139 adults 18 to 75 years (average age = 32, 64% female) with BMIs of 28 to 45. The study lasted 12 months.

The participants were divided into two groups:

A time-restricted eating group that was advised to restrict their eating to between 8 AM and 4 PM (an 8-hour window) each day.

A calorie restricted group that was given no time limitations on when they could eat.

Both groups:

Were told to reduce calories by 25% which represented a 1500-1800 calorie/day diet for men and a 1200-1500 calorie/day diet for women.

Received dietary information booklets that provided portion advice and sample menus.

Were required to write in a daily dietary log, photograph the food they ate, and note the time they ate it using a mobile app.

Received follow up phone calls or app messages twice per week and met with trained health coaches every two weeks.

Is Time Restricted Eating Better Than Other Diets?

Here are the results of the two studies.

Study 1: There was no difference between the time-restricted group and the group who were just told to cut calories at either 12 or 39 weeks for:

Weight loss.

Body composition (fat loss and lean muscle mass loss).

Appetite and eating behaviors.

HDL cholesterol, LDL cholesterol, total cholesterol, and HbA1c (a measure of blood sugar control).

The authors concluded two things:

“Time-restricted eating with caloric restriction was found to be an acceptable dietary strategy, resulting in similar levels of adherence and weight loss compared to caloric restriction alone.”

2) “The addition of behavioral support and caloric restriction to a time-restricted eating intervention results in a clinically significant weight loss, a reduction in caloric input, and an improvement in diet quality.”

Study 2: There was no difference between the time-restricted group and the group who were just told to cut calories at 12 months for:

Weight loss, BMI, and waist circumference.

Body composition (fat loss and lean muscle mass loss).

Appetite and eating behaviors.

Blood pressure, HDL cholesterol, LDL cholesterol, total cholesterol, fasting blood sugar levels, and several measures of blood sugar control.

The authors concluded, “Among patients with obesity, a regimen of time-restricted eating was not more beneficial with regard to reduction in body weight, body fat, or metabolic risk factors than daily caloric restriction.”

Is Time-Restricted Eating Right For You?

The take-home lessons are the same for both studies.

You can forget the metabolic mumbo-jumbo of the Dr. Strangeloves of our world. When you restrict calories to the same extent, time-restricted eating is no more successful and no healthier than any other diet.”

2) Like any other diet, time-restricted eating works best when you focus on eating healthy foods and reducing your caloric intake.

So, what does this mean for you? I have two thoughts:

1) If you find it easier to cut calories by restricting the time you eat, then time-restricted eating is right for you. If not, choose a healthy, reduced calorie diet that best fits your food preferences and lifestyle.

2) Time-restricted eating works best when you are in complete control of when and what you eat. They don’t work as well for travel, holidays with friends and family, and other social occasions. If your lifestyle is such that you are often not in control of when and what you eat, you might want to choose a more flexible diet.

The Bottom Line

But is this true? Two recent studies tested the hypothesis that time-restricted eating offers a special advantage by cutting calories to the same extent for people following a time-restricted eating pattern and people who had no restrictions on when they ate.

Both studies found there was no difference between the time-restricted group and the group who were just told to cut calories for:

Weight loss.

Body composition (fat loss and lean muscle mass loss).

Appetite and eating behaviors.

HDL cholesterol, LDL cholesterol, total cholesterol, and HbA1c (a measure of blood sugar control).

The take-home lessons are the same for both studies.

You can forget the metabolic mumbo-jumbo of the Dr. Strangeloves of our world. When you restrict calories to the same extent, time-restricted eating is no more successful and no healthier than any other diet.”

2) Like any other diet, time-restricted eating works best when you focus on eating healthy foods and reducing your caloric intake.

For more information on this study and a discussion of whether time-restricted eating might be right for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

___________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

Tips For Successful Weight Loss

January 3, 2023 by Dr. Steve Chaney

Which Diet Is Best?

Author: Dr. Stephen Chaney

It’s the beginning of January. Weight loss season has just launched again. Like millions of Americans, you have probably set a goal to eat healthier, lose weight, or both. But which diet is best? Vegan, Paleo, Keto, 360, Intermittent Fasting, low-carb, low fat – the list is endless.

And then there are the commercial diets: Meal replacements, low calorie processed foods, prepared meals delivered to your door – just to name a few of the categories.

You can choose to count calories, focus on portion sizes, or keep a food journal.

And, if you really want to live dangerously, you can try the latest diet pills that claim to curb your appetite and rev up your metabolism.

The advertisements for all these diets sound so convincing. They give you scientific-sounding mumbo jumbo to explain why they work. Then they talk about clinical studies they say prove their diet works.

If you are like most Americans, you have already tried several of these diets. They worked for a while, but the pounds came back – and brought their friends with them.

But, as the saying goes, “Hope springs eternal in the human breast”. Surely some diet you haven’t tried yet will work for you.

There are such diets. But they will require effort. They will require a change of mindset. There is no magic wand that will chase the extra pounds away forever.

If you are searching for the perfect diet to start the new year, let me be your guide. Here are:

4 tips on mistakes to avoid and…

6 tips on what to look for…

7 tips for making weight loss permanent…

…when you are choosing the best diet for you.

Mistakes To Avoid When Choosing The Best Diet

1. Endorsements

Endorsements by your favorite athlete or public person are paid for. They don’t necessarily represent their opinion. Nor do they assure you that they follow that diet or use that diet supplement.

Endorsements by Dr. Strangelove and his buddies can be equally misleading. They usually tell you that the medical establishment has been lying to you, and they have discovered the “secret” to permanent weight loss and the “Fountain of Youth”.

Recommendations of the medical and scientific communities usually represent a consensus statement by the top experts in their field. I would choose their advice over Dr. Strangelove’s opinion any day.

2) Testimonials

Most of the testimonials you see online or in print are either paid for or are fake.

Testimonials by your friends can be equally misleading. We are all different. What works for your friend or for your trainer may not work for you.

For example, some of us do better on low-carb diets, and others do better on low fat diets.

[Note: Some DNA testing companies claim they can sequence your DNA and tell you which diet is best. However, as I reported in a recent article in “Health Tips From The Professor”, independent studies show that DNA testing is of no use in predicting whether low-carb or low-fat diets are better for you.]

3) Diets Based on “Magic” Or “Forbidden” Foods or Food Groups.

I have often said we have 5 food groups for a reason. Each food group provides a unique blend of nutrients and phytonutrients. And each plant food group provides a unique blend of fibers that support the growth of different types of friendly gut bacteria.

The bottom line is that each of us does better with some foods than others, but there are no “magic” or “forbidden” foods that apply to everyone.

4) “Magic” Diets.

I have written perhaps the first diet book, “Slaying The Food Myths”, that doesn’t feature a “magic” diet that is going to make the pounds melt away and allow you to live to 100. Instead, I recommend a variety of healthy diets and suggest you choose the one that fits you best.

However, I understand the allure of “magic” diets. Dr. Strangelove claims the diet will be effortless. He gives you some scientific-sounding mumbo-jumbo to convince you the diet is scientifically sound. Then he cites some clinical studies showing the diet will cause you to lose weight and will improve your health parameters (things like cholesterol, triglycerides, blood sugar, and blood pressure). It sounds so convincing.

Before you fall for Dr. Strangelove’s latest “magic” diet, let me share two things that may blow your mind:

The studies are all short-term (usually 3 months or less).

When you rely on short-term studies, the very low-fat Vegan diet and very low-carb Keto diet give you virtually identical weight loss and improvement in health parameters!

Those two diets are as different as any two diets could be. That means we can forget all the scientific-sounding mumbo-jumbo as to why each of those diets work. Instead, we should ask what these two diets have in common.

The answer is simple:

#1: The clinical studies are comparing “magic” diets to the typical American diet. Anything is better than the typical American diet! It is high in sugar, refined carbohydrates, saturated fat, and highly processed foods. No wonder the “magic” diets look so good.

#2: The diets are whole food diets. Anytime you eliminate sodas, fast foods, and highly processed foods, you will lose weight.

#3: The diets eliminate one or more food groups. Whenever you eliminate some of your favorite foods from your diet, you tend to lose weight without thinking about it. I call this the cream cheese and bagel phenomenon.

If you are following a low-fat diet, it sounds great to say you can eat all the bagels you want. But without cream cheese to go with the bagels, you tend to eat fewer bagels.

If you are following a low-carb diet, it sounds great to say you can eat as much cream cheese as you want, but without bagels to go with your cream cheese, you tend to eat less cream cheese.

#4: Because they eliminate many of your favorite foods, “magic” diets make you focus on what you eat. Whenever you focus on what you eat, you tend to lose weight. That is why food journals and calorie counters are effective.

#5: Finally, whenever you lose weight, your health parameters (cholesterol, triglycerides, blood sugar, and blood pressure) improve.

Tips For Successful Weight Loss

What should you look for in choosing a healthy weight loss diet? Here are my top 6 tips.

1. Choose whole food diets. Avoid sodas, fast foods, and highly processed foods.

2) Choose primarily plant-based diets. These can range from Vegan through semi-vegetarian, Mediterranean, DASH, and Nordic. All are healthy diets. I have discussed the evidence for this recommendation in my book “Slaying The Food Myths”. Here is a brief summary.

When we look at long term (10-20 year) studies:

Vegetarians weigh less and are healthier than people consuming the typical American diet.

People consuming semi-vegetarian, Mediterranean, and DASH diets are healthier than people consuming the typical American diet.

When we look at low-carb diets:

People consuming plant-based low-carb diets weigh less and are healthier than people consuming the typical American diet.

People consuming meat-based low-carb diets are just as fat and unhealthy as people consuming the typical American diet.

The Atkins low-carb diet has been around for more than 50 years, and there is no evidence it is healthy long-term.

3) Choose diets that include a variety of foods from all 5 food groups. I have discussed the rationale for that recommendation above.

4) Choose diets that consider meat as a garnish, not a main course.

5) Choose diets that feature healthy carbs and healthy fats rather than low-carb or low-fat diets.

6) Think lifestyle, not diet. If you choose a restrictive diet so you can achieve quick weight loss, you will probably be just as fat and unhealthy next December 31^st as you are this year. Instead, choose diets that teach healthy eating and lifestyle changes that you can make a permanent part of your life.

Tips For Keeping The Weight Off

You know the brutal truth. Around 95% of dieters regain everything they lost and then some within a few years. You have probably gone through one or more cycles of weight loss and regain yourself – something called “yo-yo dieting”. You may even be asking yourself if it is worth bothering to try to lose weight this year.

Rather focusing on the negative statistics of weight loss, let’s look at the good news. There are people who lose the weight and keep it off. What do they do?

There is an organization called the National Weight Control Registry that has enrolled more than 10,000 people who have lost weight and kept it off. The people in this group lost weight on almost every diet imaginable. However, here is the important statistic: On average people in this group have lost 66 pounds and kept it off for at least 5 years.

The National Weight Control Registry has kept track of what they have done to keep the weight off. Here is what they do that you may not be doing:

1. They consume a reduced calorie, whole food diet.

2) They get lots of exercise (around 1 hour/day).

3) They have internalized their eating patterns. In short, this is no longer a diet. It has become a permanent part of their lifestyle. This is the way they eat without even thinking about it.

4) They monitor their weight regularly. When they gain a few pounds, they modify their diet until they are back at their target weight.

5) They eat breakfast on a regular basis.

6) They watch less than 10 hours of TV/week.

7) They are consistent (no planned cheat days).

Which Diet Is Best?

Now it is time to get back to the question you are asking right now, “Which diet is best?” I have covered a lot of ground in this article. Let me summarize it for you.

If you are thinking about popular diets:

Primarily plant-based diets ranging from Vegan to Mediterranean and Dash are associated with a healthier weight and better health long term.

- If want to lose weight quickly, you may want to start with the more restrictive plant-based diets, like Vegan, Ornish, Pritikin or semi-vegetarian.

- If you do better with a low-carb diet, my recommendation is the lower-carb version of the Mediterranean diet called Med-Plus. It is a whole food version of the Mediterranean diet that minimizes added sugar and refined grains (I will be talking more about it in next week’s “Health Tips From the Professor”).

- If your primary goal is rapid weight loss, you could also start with one of the healthier of the restrictive low-carb diets, like the Paleo or the 360 diet. I do not recommend the Keto diet.

No matter what diet you start with, plan to transition to the primarily plant-based diet that best fits your lifestyle and food preferences. This is the diet you will want to stick with to maintain your weight loss and achieve better health long term.

Plan on permanent lifestyle change rather than a short-term diet. Otherwise, you are just wasting your time.

Eat whole foods. Big Food keeps up with America’s favorite diets and is only too happy to sell you highly processed foods that match your favorite diet. Avoid those like the plague.

If you are thinking about commercial diets featuring meal replacement products:

Look for meal replacement products that:

- Do not contain artificial sweeteners, flavors, or preservatives.

- Use non-GMO protein. A non-GMO certification for the other ingredients is not necessary. For a more detailed explanation of when non-GMO certification is important and when it is unnecessary, see my article in “Health Tips From the Professor”.

- Have stringent quality controls in place to assure purity. “Organic” and/or “non-GMO” on the label do not assure purity.

Look for programs that can provide clinical studies showing their diet plan is effective for weight loss and for keeping the weight off. Many programs have short-term clinical studies showing they are effective for weight loss, but very few have longer-term studies showing the weight stays off.

Finally, look for programs that teach permanent lifestyle change. This should include guidance on exercise and healthy eating.

I do not recommend most commercial diets that feature prepared low-calorie foods “shipped right to your door” as a major part of their program. The foods are highly processed. Plus, they include all your favorite unhealthy foods as part of the program. Even if they include lifestyle change as part of their program, they are undermining their message with the foods they are providing you.

I would be remiss if I didn’t mention that Weight Watchers is highly recommended by most experts in the field. Weight Watchers emphasizes journaling and counting calories, which is a plus because it makes you focus on what you are eating. They also have a good lifestyle program and support that can help you transition to permanent lifestyle change if you are willing to put in the effort. However, I don’t recommend their prepared low-calorie foods. They are no better than foods provided by the other commercial diet programs.

The Bottom Line

Weight loss season is upon us. If you plan to lose weight and/or adopt a healthier diet this year, you are probably asking, “Which Diet Is Best?” In this issue of “Health Tips From The Professor” I give you:

4 tips on mistakes to avoid when selecting the diet that is best for you.

6 tips on how to choose the best diet.

5 tips on what to look for when selecting a diet featuring meal replacement products.

7 tips on how to keep the weight off.

Then I put all this information together to help you choose the best diet, the best meal replacement product, and/or the best commercial diet program.

For more details read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Does Time-Restricted Eating Have A Downside?

January 25, 2022 by Dr. Steve Chaney

Are The Benefits Of Time-Restricted Eating An Illusion?

Author: Dr. Stephen Chaney

Weight loss is difficult. If you are like most American adults, you have tried at least 5 or 6 diets by the time you are 50, and all of them have failed. Or maybe you have found a diet that works reasonably well at helping you lose weight, but it’s difficult to stick with. And you worry that it may not be healthy long-term.

But hope springs eternal, and there are always new diets to try. One of the newer diet fads is something called intermittent fasting. The most popular form of intermittent fasting (because it is the easiest to follow) is something called time-restricted eating.

The concept is simple. You don’t change what you are eating. Instead, you restrict the time during which you are eating those foods. Typically, you restrict your time of eating to 8 hours a day and abstain from all food the rest of the day. Hence, the term “time-restricted eating”.

I won’t go into the supposed benefits of time-restricted eating. You have probably heard those already from advocates of this form of eating. But you may be wondering if those benefits are true and whether time-restricted eating has any drawbacks.

Fortunately, a recent study (T Moro et al, Medicine and Science In Sports & Exercise, 53, 2577-2585, 2021) answers those questions. It put a group of athletes on either a control diet or a time-restricted diet for an entire year and looked at the relative benefits and drawbacks of both diets.

How Was This Study Done?

This study recruited 19 healthy, resistance-trained males (average age = 29, average weight = 185 pounds) for the study. All the subjects had at least 5 continuous years of resistance training, no steroid use, and no known medical conditions.

The subjects completed a 7-day food diary prior to the study, at the end of 2 months, and at the end of 12 months. The participants were instructed not to change their usual caloric intake or diet composition. In addition, each participant received a personalized diet protocol based on the analysis of their food diary at baseline.

The results from the first two months have previously been reported (T Moro et al, Journal of Translational Research, 14: 290, 2016). This report covers the subsequent 10 months.

During the first two months, the participants were contacted weekly by a dietitian to ensure adherence to the diet. During the interviews, the dietitian asked questions about meal timing and composition, appetite, and any difficulties in maintaining the diet protocol. When necessary, the dietitian gave advice to improve adherence to the diet. During the subsequent 10 months, the participants were contacted less frequently, and the interviews were shorter.

The participants were divided into two groups. The selection was random except that the two groups were matched with respect to caloric intake at baseline (~2,900 calories/day).

The ND (normal meal distribution) group ate their meals over a 12-hour period, with meals at ~8AM, 1 PM, and 8 PM. The distribution of calories for this group was 25%, 40%, and 35% over the three meals.

The TRE (time-restricted eating) group ate their meals over an 8-hour period, with meals at ~1PM, 4 PM, and 8 PM. The distribution of calories for this group was 40%, 25%, and 35% over the three meals.

The training regimen consisted of strength training specifically designed to increase muscle mass. A standardized 3-times per week training regimen was established during the first two months of supervised training. The participants continued the same training regimen on their own for the next 10 months. Workouts were performed between 4 and 6 PM to fall within the eating window for both groups.

Finally, tests for inflammatory markers, cholesterol & other blood lipids, blood sugar control, hormones, body composition, and strength were performed before the program started, at 2 months, and again at 12 months.

What Are The Benefits Of Time Restricted Eating?

When the investigators looked at health outcomes at the end of 12 months:

Inflammatory markers were significantly reduced in the TRE (time-restricted eating) group compared to the ND (normal meal distribution) group.

Blood sugar control was significantly improved in the TRE group compared to the ND group.

Lipid profiles were significantly improved in the TRE group compared to the ND group.

These results are consistent with the findings of earlier short-term studies on the benefits of time restricted eating.

The authors concluded. “Our results suggest that long-term time-restricted eating in combination with a resistance training program is feasible, safe, and effective in reducing inflammatory markers and risk factors.”

At this point you are probably thinking, “It sounds like everything I have heard about time-restricted eating is true. I can’t wait to get started.”

What Causes The Benefits Of Time-Restricted Eating?

Before you jump on the time restricted eating bandwagon, let’s look more closely and ask what caused these apparent health benefits.

When the investigators looked at changes in caloric intake over the 12-month period:

The TRE group spontaneously decreased their total caloric intake by 6.4% in spite of being told not to change their diet.

- The decrease in caloric intake was driven by a decrease in both carbohydrate and fat intake, while protein intake remained constant.

- Most of this change occurred between 2 and 12 months when they were no longer being closely supervised by dietitians.

In contrast, caloric intake and macronutrient intake did not change significantly for the ND group.

The reason for the decrease in caloric intake is not known.

If you follow social media or blogs about time-restricted eating, you have been given some scientific-sounding mumbo-jumbo about how the 16 hours of fasting changes your metabolism and/or reduces your appetite. However, this is speculation. There is scant evidence for it.

A more likely explanation is that when you restrict the time you allow yourself to eat, you naturally eat less without thinking about it. You are simply less hungry when the second and third meals roll around. [This may explain why even these highly disciplined athletes required weekly coaching by dietitians to keep their caloric intake constant.]

And when the investigators looked at changes in body weight over the 12-month period:

The TRE group lost 3.4% of their body weight.

- Most of that weight loss was due to a decrease in fat mass, but there was also a loss of muscle mass.

In contrast the ND group increased their total body weight by 3.4%.

- In other words, at the end of 12 months the difference between the TRE and ND groups amounted to almost 7% of their body weight. This difference was highly significant.

- Most of the increase in body weight in the ND group was due to a 2.9% increase in muscle mass.

These results are also consistent with the findings of earlier studies of time-restricted eating.

The observed decrease in body weight and fat mass is important because whenever you decrease body weight and fat mass, you:

Reduce inflammatory markers.
Improve blood sugar control.
Improve lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

Of course, that still sounds pretty good. Who wouldn’t want to lose weight and get healthier? But are the weight reduction and health benefits unique to time-restricted eating? That is the claim of those who promote this diet.

But is it true? To answer that question, we need to take a broader view of popular diets. We need to ask, “Is something special about time-restricted eating, or would other restrictive diets give similar results?”

Are The Benefits Of Time-Restricted Eating An Illusion?

There are two diet truths that nobody is talking about:

1) Forget the metabolic mumbo-jumbo. The primary reason restrictive diets cause you to lose weight is that you unconsciously eat less while you are on these diets.

For time-restricted eating, you eat less because you have restricted the time when you can eat. With other restrictive diets, you have restricted the foods you can eat. The reason why that causes you to eat less is more subtle. I call it the “Bagels and Cream Cheese Effect”.

- When you go on a low-fat diet, it sounds great to say you can eat all the bagels you want. But without the cream cheese, bagels become boring, and you eat less.

- When you go on a low-carb diet, it sounds great to say you can eat all the cream cheese you want. But without the bagels, cream cheese becomes boring, and you eat less.

2) The proponents of fad diets make them look good by comparing them to the typical American diet. Anything is better than the American diet. However, when you make the comparisons based on the reduction in caloric intake or the amount of weight lost, the health benefits of popular diets are virtually identical. For example:

- When you compare the Atkins diet and other low carb diets with the typical American diet, inflammation is lower on the low carb diets. However, one recent study compared people on the Atkins diet with people who had lost an equal amount of weight on a balanced diet that included all food groups. Guess what? Inflammation is much higher on the Atkins diet when you compare it to a healthy diet that gives equal weight loss.

- This study reported that the time-restricted eating group ate less, lost more weight, and had better health parameters than the control group. However, previous studies that compared time-restricted eating with groups that reduced caloric intake to the same extent by simply counting calories have found the two groups had identical weight loss and improvement in health parameters.

In other words, there is nothing magical about time-restricted eating. Any diet that causes you to eat less will give identical results. There are only two questions left:

Can you stick with time-restricted eating long term?

Time-restricted eating is not everyone’s cup of tea. But this study suggests that if you can stick with it better than with other restrictive diets, you are likely to lose weight and reap some health benefits.

2) Should you stick with time-restricted eating long term?

To answer this question, you need to know whether there are any downsides to time-restricted eating.

Does Time-Restricted Eating Have A Downside?

Of course, most people would consider weight loss and an improvement in health parameters as a definite plus. It’s all good. Or is it? Does time-restricted eating have any downsides? This study identified two potential downsides:

1) Decreased anabolic hormones.

- Anabolic hormones (hormones that stimulate an increase in muscle mass) were decreased in the TRE group. Specifically:

- - Testosterone was decreased by 17% at the end of 12 months in the TRE group.

- - Insulin-like growth factor-1 (IGF-1) was decreased by 14% in the TRE group.

- Both anabolic hormone levels were unchanged in the ND group.

2) Decreased muscle mass. Between months 2 and 12:

- Muscle mass was decreased by 2.3% in TRE group and increased by 2.9% in the ND group.

- The cross-sectional area of arm and thigh muscles was decreased by an average of 4.3% in the TRE group and increased by an average of 8.5% in the ND group.

In the words of the authors, “With our results, we confirmed that a long-term TRE protocol could impair the ability of maintaining muscle mass, possibly because of a reduction in caloric intake and a direct effect of fasting on the production of anabolic hormones.”

That is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. So, a continuous increase in muscle mass and cross-sectional area would be expected. This was seen in the ND group but not in the TRE group, which actually lost muscle mass. The average “Joe” or “Jane” would likely lose even more muscle on this diet.

And continuous, long-term loss of muscle mass has significant health consequences including:

Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
Decreased insulin sensitivity, which increases the risk of diabetes.
Increased risk of osteoporosis.
Muscle weakness, which increases the risk of falling.

Dr. Paoli, the lead scientist on this study, was quoted as saying, “The main take home message is that there are pros and cons to prolonged time-restricted eating. Although time-restricted eating may produce some physiological advantages, it is not a miracle as often suggested in social media posts.”

The Bottom Line

A recent study looked at the pros and cons of following a time-restricted eating (TRE) diet compared to a diet with normal meal distribution (ND) for 12 months.

The TRE group had reduced inflammation, better blood sugar control, and better lipid profiles than the ND group.

However, the improved health parameters were not caused by some magical metabolic changes due to fasting.

The TRE group unconsciously reduced their caloric intake and lost weight compared to the ND group. And any time you lose weight, you get reduced inflammation, better blood sugar control, and better lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

And there is nothing unique about time-restricted eating.

Any restrictive diet is likely to give similar results. (For more details, read the article above.)

Finally, there were some significant downsides to time-restricted eating.

The TRE group had a reduction in anabolic hormones and lost muscle mass.

This is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. They should have gained muscle mass. Instead, they lost it.

Continuous, long-term loss of muscle mass has significant health consequences including:

Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
Decreased insulin sensitivity, which increases the risk of diabetes.
Increased risk of osteoporosis.
Muscle weakness, which increases the risk of falling.

For more details read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Does Intermittent Fasting Work?

January 7, 2020 by Dr. Steve Chaney

Will Intermittent Fasting Help You Lose Weight?

Author: Dr. Stephen Chaney

If you are like millions of Americans, one of your New Year’s resolutions is to lose weight. Now your dilemma is how to accomplish that. You have tried various diets before – Atkins, paleo, keto, Whole 30, etc. You lost some weight, but it came right back. You are looking for something new, something different from anything you have tried before.

What about intermittent fasting? It’s hot right now. It’s probably different from what you have tried in the past. It doesn’t require radical changes to what you eat. Some of your friends are singing its praises. Could this be the one that solves your weight problem forever?

A Primer On Intermittent Fasting

Let’s start by defining intermittent fasting and reviewing what we already know about it. There are several variations of what the mass media refers to as intermittent fasting, but the two most popular versions are:

Time-restricted fasting which limits daily intake of food to a 4 to 12-hour period. The most popular version of this restricts food intake to 8 hours followed by 16 hours of fasting.

Intermittent fasting in which there is a day or more of fasting or decreased food intake between periods of unrestricted eating. The most popular version of this allows 5 days of unrestricted eating followed by 2 days of fasting.

A major review (Di Francesco et al, Science, 362: 770-775, 2018) of time-restricted and intermittent fasting was published a little over a year ago. At the time that review was published, there were lots of studies comparing time-restricted fasting with continuous caloric restriction. I summarized those findings in a previous issue of “Health Tips From the Professor” last January.

Here is a brief summary of the key findings from that review:

If you read the blogs about time-restricted fasting, you will come across all sorts of metabolic mumbo-jumbo about ketone bodies, adiponectin, leptin, IGF-1, and blood glucose levels. It sounds so convincing. Don’t get sucked in by these pseudo-scientific explanations. At this point they are mostly speculation.

Although there is no conscious effort to control calories, time-restricted fasting result in an inadvertent reduction in food intake by restricting the time allowed for eating and by eliminating late night snacking. This reduction in caloric intake is likely responsible for most of the weight loss associated with intermittent fasting. When you control for calories, there is no difference in weight loss between time-restricted fasting and continuous caloric restriction (your typical reduced calorie diet).

However, at the time the review was published, far less was known about the relative benefits of intermittent fasting and simple caloric restriction. Since that time, two studies have rigorously compared the effectiveness of intermittent fasting and continuous caloric restriction on weight loss. I review those studies below

Will Intermittent Fasting Help You Lose Weight?

The first study (YM Roman et al, International Journal of Obesity, 43: 2017-2027, 2019) was a systematic review and meta-analysis of 9 clinical studies comparing intermittent fasting with continuous caloric restriction. Total caloric reduction was controlled and was the same for both intermittent fasting and continuous caloric reduction.

The studies ranged from 12 weeks to 52 weeks with most of them in the 20 to 30-week range. This meta-analysis found:

· There was no difference between intermittent fasting and continuous caloric restriction in terms of weight loss, waist circumference, or body fat loss.

· Loss of lean body mass, on the other hand, was greater for intermittent fasting than for continuous caloric restriction.

The authors concluded: “Since it is ultimately fat mass loss that improves health indices, and not the loss of muscle, the significantly greater loss of lean mass in the intermittent dieting group versus the continuous dieting group is concerning and needs to be further assessed.”

I would add, it is also concerning because lean mass muscle burns calories faster than fat mass. Loss of lean muscle mass could lead to a lower metabolic rate. That would make maintenance of the weight loss more difficult.

The second study (ML Headland et al, International Journal of Obesity, 43: 2028-2036) compared intermittent fasting versus continuous calorie restriction for 12 months in a group of 332 healthy overweight or obese adults. Again, total caloric reduction was the same for the two groups. In this study:

· There was no significant difference between intermittent fasting and continuous caloric restriction for weight loss, body fat loss, and lean body mass loss. [Note: The retention of lean body mass in this study differs from the loss of lean body mass reported in the previous study. Additional studies will be required before we become overly concerned about potential loss of lean body mass with intermittent fasting.]

· There were also no significant differences between the groups for blood levels of glucose, total cholesterol, triglycerides, HDL, and LDL.

Does Intermittent Fasting Work?

These studies make it clear there is no “magic” associated with either time-restricted or intermittent fasting.

· If either time-restricted or intermittent fasting allows you to reduce your daily caloric intake by restricting the time that you are eating, you will lose weight and keep it off. However, if you compensate for the fasting periods by consuming additional calories when you are eating, all bets are off.

· In clinical studies that restrict calories to the same extent in the various diets, neither time-restricted nor intermittent fasting results in greater weight loss than continuous caloric restriction (your typical reduced calorie diet).

o In addition, neither time-restricted nor intermittent fasting results in better improvement in blood parameters (glucose, total cholesterol, triglycerides, HDL, and LDL) than continuous caloric restriction.

· Intermittent fasting may result in greater loss of lean muscle mass than continuous caloric reduction. If confirmed by subsequent studies, this would be concerning.

This also means:

· If you happen to read the blogs about time-restricted or intermittent fasting, you can forget all the metabolic mumbo-jumbo about ketone bodies, adiponectin, leptin, IGF-1, and blood glucose levels.

o At this point this metabolic information comes mostly from animal studies. Its application to humans is purely speculation.

o Since time-restricted and intermittent fasting offer no advantage over continuous caloric restriction, there is no evidence that changes in any of those metabolic markers has any effect on weight loss in humans.

Finally, you need to ask whether time-restricted and intermittent fasting are something you can maintain in the real world.

· Your friends are unlikely to be on the same schedule. It won’t be easy to fit your diet around socializing, travel, and holidays.

The Bottom Line

There are several variations of what the mass media refers to as intermittent fasting, but the two most popular versions are:

Time-restricted fasting which limits daily intake of food to a 4 to 12-hour period. The most popular version of this restricts food intake to 8 hours followed by 16 hours of fasting.

Intermittent fasting in which there is a day or more of fasting or decreased food intake between periods of unrestricted eating. The most popular version of this allows 5 days of unrestricted eating followed by 2 days of fasting.

The latest studies make it clear there is no “magic” associated with either time-restricted or intermittent fasting.

· Intermittent fasting may result in greater loss of lean muscle mass than continuous caloric reduction. If confirmed by subsequent studies, this would be concerning.

Finally, you need to ask whether time-restricted and intermittent fasting are something you can maintain in the real world.

· Your friends are unlikely to be on the same schedule. It won’t easy to fit your diet around socializing, travel, and holidays.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

What Are Intermittent Fasting Benefits?

January 8, 2019 by Dr. Steve Chaney

Will Intermittent Fasting Make You Leaner & Healthier?

Author: Dr. Stephen Chaney

Intermittent fasting is all the rage. If you believe the hype, intermittent fasting will make you leaner and healthier. Some of its proponents claim you don’t even need to give up your favorite foods. You don’t need to give up your Big Macs for fruits and vegetables. You don’t need to restrict what you eat. You just need to restrict when you eat.

If you read the blogs about intermittent fasting, you will come across all sorts of metabolic mumbo-jumbo about ketone bodies, adiponectin, leptin, IGF-1, and blood glucose levels. It sounds so convincing. Don’t get sucked in by these pseudo-scientific explanations. At this point they are mostly speculation.

What are intermittent fasting benefits?

Instead, ask “What is the evidence that intermittent fasting works?” More importantly, ask “What is the evidence it works in human?” Most of the studies have been done in animal model systems. Claims based on animal models may not apply to humans.

This week I will discuss a review on caloric restriction and various forms of fasting that recently appeared in Science, one of the most highly respected scientific journals (Di Francesco et al, Science, 362: 770-775, 2018 ).

This article was a comprehensive review of three closely-related dietary approaches:

Caloric restriction in which daily caloric intake is restricted by 15-40%.
Time-restricted fasting which limits daily intake of food to a 4-12 hour period.
Intermittent fasting in which there is a day or more of fasting or decreased food intake between periods of unrestricted eating.

Note:

What the review calls time-restricted fasting is referred to in the mass media as intermittent fasting. What the review calls intermittent fasting is referred to in the mass media as alternate day fasting. To avoid confusion, I will use the mass media definitions.
I will focus on what the mass media refers to as intermittent fasting and just briefly summarize the other two approaches.

Will Caloric Restriction Allow You To Live Longer?

The concept of caloric restriction has been around for a long time and is the best studied of the dietary approaches covered in this review. In brief:

Caloric restriction has been studied in animal model systems ranging from mice to primates. In every animal model studied, caloric restriction reduced the incidence of age-related degenerative diseases and increased either life span or health span or both.
In both animal model systems and humans, caloric restriction lowers cholesterol, lowers blood pressure, improves blood sugar control, reduces inflammation, and reduces oxidative damage.
Populations that eat a healthy diet and practice voluntary caloric restriction appear to enjoy remarkable longevity.
The effects of caloric restriction appear to operate via the sirtuin anti-aging pathway. Most of the other effects are downstream of this pathway.
The effects of caloric restriction (including activation of the sirtuin pathway) are mimicked by resveratrol and related polyphenols.

In short:

Caloric restriction and some naturally occurring compounds such as resveratrol are clearly effective in animal model systems and are likely to be effective in humans.
However, we live too long to allow definitive studies of the effect of caloric restriction on human life span and health span.
This dietary approach has never gained popularity because very few people want to starve themselves just so they can live a longer, healthier life.

Intermittent Fasting Benefits: Leaner & Healthier?

There are many variations to intermittent fasting. As the review stated, intermittent fasting can mean that food consumption is restricted to anywhere from 4 to 12 hours. However, the most popular version of intermittent fasting at present restricts food consumption to 8 hours followed by a 16-hour period of fasting. Here is what you need to know about intermittent fasting:

Once again, most of the studies have been done in rodents. Those studies appear to show that intermittent fasting results in weight loss, improved blood sugar control, lower cholesterol and triglyceride levels and reduced inflammation even when caloric intake remains unchanged. These findings have generated the claims you see in the media. However, you need to remember that what works in rodents does not necessarily work in humans.
Unlike caloric restriction, the benefits of intermittent fasting are dependent on circadian rhythm. [Note: If you are unfamiliar with the concept of circadian rhythm, it is a master control that is genetically hardwired into almost every organism on the planet, including humans. In general, circadian rhythm is synchronized with the light-dark cycle.] The effect of circadian rhythm that is relevant to this discussion is that metabolic rate and many of the enzymes involved in food metabolism in humans are more active during the day than at night. Not surprising, animal studies suggest that intermittent fasting is most effective when the feed-fast cycle is synchronized with their circadian rhythm.
The timing of the feeding portion of the intermittent fasting cycle also appears to be important for humans. According to the review by Di Francesco et al, the few clinical studies that have been performed on humans show:
Limiting food intake to the middle of the day decreased glucose levels, cholesterol & triglyceride levels, and inflammation.
Eating a larger breakfast and smaller dinner improved metabolic markers better than when participants ate a smaller breakfast and larger dinner.
Type 2 diabetics attained better blood sugar control when most of their calories were consumed in the first half of the day. In contrast, restricting their calories to late afternoon or evening resulted in either no blood sugar improvement or a worsening of blood sugar controls.
Finally, subjects lost more weight on a reduced calorie diet when most of the food was consumed in the morning rather than in the evening.
If you read the very popular “Obesity Code” book by Dr. Fung you will discover he is recommending a diet that consists of fruits & vegetables, fiber-rich foods, healthy protein & healthy fats, and avoids sugar, refined grains, and processed foods. He also recommends avoiding snacking. That is exactly the kind of diet I recommend in my book, “Slaying The Food Myths.” If the average American adopted that diet and did nothing else, they would be leaner and healthier. So much for the claim that you can eat all your favorite junk foods and become leaner and healthier by intermittent fasting.
Finally, most of the human clinical studies have carefully controlled caloric intake. From these studies it is apparent that many of the metabolic benefits of intermittent fasting come from synchronizing your food intake with your circadian rhythm. However, in those studies that focused on time of eating and did not control calories, food intake was reduced by intermittent fasting. This is the unacknowledged benefit of intermittent fasting. When you restrict the time period for eating and restrict snacking you generally end up eating less. Thus, the weight loss associated with intermittent fasting may be caused by reduced caloric intake rather than fasting.

What Does This Mean For You? Here are the take-home lessons from this review:

Most of the studies on intermittent fasting have been done with animals, not with humans.
Both animal and human studies suggest that the benefits of intermittent fasting result from synchronizing your food intake with your circadian rhythm. The old adage of “Eat breakfast like a king, lunch like a prince, and dinner like a pauper” may be true for most of us. [Note: Circadian rhythms vary slightly from person to person. Some people will do better by their fast at mid-day rather than at breakfast. However, they will probably still benefit by eating a bigger meal mid-day and a smaller meal in the evening.]
Although there is no conscious effort to control calories, intermittent fasting appears to result in an inadvertent reduction in food intake by restricting the time allowed for eating and by eliminating late night snacking. This reduction in caloric intake is likely responsible for much of the weight loss associated with intermittent fasting.
In summary, intermittent fasting appears to work, but it is not clear whether you need to follow a rigid schedule of eating and fasting. The available clinical studies suggest that if you eat a healthy, primarily plant-based diet, eat most of your calories early in the day, don’t snack between meals, and don’t eat anything after dinner, you will obtain most, if not all, of the benefits attributed to intermittent fasting.

If you define intermittent fasting that way, the professor has been doing intermittent fasting for years. He just didn’t know that was what he was doing.

Does Alternate Day Fasting Make You Healthier?

Fasting regimens promoted for weight loss typically involve one or several days in which no or few calories are consumed followed by a period of unrestricted eating.

At present, the two most popular regimens are the alternate day fast and the alternate day modified fast. The alternate day fast involves a 24-hour water fast followed by a normal feeding period of 24-hours. The alternate day modified fast reduces caloric intake to 25% of normal on fasting days. Here is a brief summary of what we know about alternate day fasting:

Once again, most of the studies have been done in animals.
Since neither animals nor humans generally consume double their normal caloric intake during the 24-hour feeding period, alternate day fasting results in an overall reduction in caloric intake. Not surprisingly, the benefits of alternate day fasting in animal studies are similar to the benefits observed with caloric restriction.
Short-term human clinical trials suggest that alternate day fasting results in weight loss. The weight loss causes an improvement in blood sugar control, lower blood pressure, and lower cholesterol & triglyceride levels. Based on these studies, alternative day fasting is likely to be an effective strategy for short-term weight loss and has some short-term health benefits.
However, there are no long-term studies on the effectiveness of this approach. It is highly unlikely that most people would be able to follow this regimented a diet plan long term. Thus, it is also unlikely that the weight loss and health benefits can be maintained long term.
Finally, fasting is not for everyone. It is generally not recommended for people who are hypoglycemic, the elderly, pregnant women, and people with eating disorders.

The Bottom Line

In this article I discussed a recent review of intermittent fasting and other approaches that involved fasting or long-term caloric restriction. Here are the take-home lessons on intermittent fasting:

Most of the studies on intermittent fasting have been done with animals, not with humans. Many of the claims you hear about on the benefits of intermittent fasting are based on the animal studies. They may not apply to humans.
Both animal and human studies suggest that the benefits of intermittent fasting result from synchronizing your food intake with your circadian rhythm. The old adage of “Eat breakfast like a king, lunch like a prince, and dinner like a pauper” may be true for most of us. [Note: Circadian rhythms vary slightly from person to person. Some people will do better by breaking their fast at mid-day rather than at breakfast. However, they will probably still benefit by eating a bigger meal mid-day and a smaller meal in the evening.]
Although there is no conscious effort to reduce calories, intermittent fasting appears to result in an inadvertent reduction in food intake by restricting the time allowed for eating and by eliminating late night snacking. This reduction in caloric intake is likely responsible for much of the weight loss associated with intermittent fasting.
In summary, intermittent fasting appears to be beneficial, but it is not clear whether you need to follow a rigid schedule of eating and fasting. The available clinical studies suggest that if you eat a healthy, primarily plant-based diet, eat most of your calories early in the day, don’t snack between meals, and don’t eat anything after dinner, you will obtain most, if not all, of the benefits attributed to intermittent fasting. If you define intermittent fasting that way, the professor has been doing intermittent fasting for years. He just didn’t know that was what he was doing.

For more details on intermittent fasting and for a discussion of long-term caloric restriction and alternate day fasting read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.