What Is The Truth About Low Carb Diets?

Why Is The Cochrane Collaboration The Gold Standard?

Author: Dr. Stephen Chaney 

low carb dietAtkins, South Beach, Whole30, Low Carb, high Fat, Low Carb Paleo, and Keto. Low carb diets come in many forms. But they have these general characteristics:

  • They restrict carbohydrate intake to <40% of calories.
  • They restrict grains, cereals, legumes, and other carbohydrate foods such as dairy, fruits, and some vegetables.
  • They replace these foods with foods higher in fat and protein such as meats, eggs, cheese, butter, cream, and oils.
  • When recommended for weight loss, they generally restrict calories.

What about the science? Dr. Strangelove and his friends tell you that low carb diets are better for weight loss, blood sugar control, and are more heart healthy than other diets. But these claims are controversial.

Why is that? I have discussed this in previous issues of “Health Tips From The Professor”. Here is the short version.

  • Most studies on the benefits of low carb diets compare them with the typical American diet.
    • The typical American diet is high in fat, sugar and refined flour, and highly processed foods. Anything is better than the typical American diet.
  • Most low carb diets are whole food diets.
    • Any time you replace sodas and highly processed foods with whole foods you will lose weight and improve your health.
  • Most low carb diets are highly structured. There are rules for which foods to avoid, which foods to eat, and often additional rules to follow.
    • Any highly structured diet causes you to focus on what you eat. When you do that, you lose weight. When you lose weight, your health parameters improve.
    • As I have noted before, short term weight loss and improvement in health parameters are virtually identical for the very low carb keto diet and the very low-fat vegan diet.

With all this uncertainty you are probably wondering, “What is the truth about low carb diets?”

A recent study by the Cochrane Collaboration (CE Naude et al, Cochrane Database of Systematic Reviews, 28 January 2022) was designed to answer this question.

The Cochrane Collaboration is considered the gold standard of evidence-based medicine. To help you understand why this is, I will repeat a summary of how the Cochrane Collaboration approaches clinical studies that I shared two weeks ago.

Why Is The Cochrane Collaboration The Gold Standard?

ghost bustersWho you gonna call? It’s not Ghostbusters. It’s not Dr. Strangelove’s health blog. It’s a group called the Cochrane Collaboration.

The Cochrane Collaboration consists of 30,000 volunteer scientific experts from across the globe whose sole mission is to analyze the scientific literature and publish reviews of health claims so that health professionals, patients, and policy makers can make evidence-based choices about health interventions.

In one sense, Cochrane reviews are what is called a “meta-analysis”, in which data from numerous studies are grouped together so that a statistically significant conclusion can be reached. However, Cochrane Collaboration reviews differ from most meta-analyses found in the scientific literature in a very significant way.

Many published meta-analyses simply report “statistically significant” conclusions. However, statistics can be misleading. As Mark Twain said: “There are lies. There are damn lies. And then there are statistics”.

The Cochrane Collaboration also reports statistically significant conclusions from their meta-analyses. However, they carefully consider the quality of each individual study in their analysis. They look at possible sources of bias. They look at the design and size of the studies. Finally, they ask whether the conclusions are consistent from one study to the next. They clearly define the quality of evidence that backs up each of their conclusions as follows:

  • High-quality evidence. Further research is unlikely to change their conclusion. This is generally reserved for conclusions backed by multiple high-quality studies that have all come to the same conclusion. These are the recommendations that are most often adopted into medical practice.
  • Moderate-quality evidence. This conclusion is very likely to be true, but further research could have an impact on it.
  • Low-quality evidence. Further research is needed and could alter the conclusion. They are not judging whether the conclusion is true or false. They are simply saying more research is needed to reach a definite conclusion.

This is why their reviews are considered the gold standard of evidence-based medicine. If you are of a certain age, you may remember that TV commercial “When EF Hutton talks, people listen.” It is the same with the Cochrane Collaboration. When they talk, health professionals listen.

How Was The Study Done?

Clinical StudyThe authors of this Cochrane Collaboration Report included 61 published clinical trials that randomized participants into two groups.

  • The first group was put on a low carbohydrate diet (carbohydrates = <40% of calories).
  • The second group was put on a “normal carbohydrate” diet (carbohydrates = 45-65% of calories, as recommended by the USDA and most health authorities).
    • The normal carbohydrate diet was matched with the low carbohydrate diet in terms of caloric restriction.
    • Both diets were designed by dietitians and were generally whole food diets.

The participants in these studies:

  • Were middle-aged.
  • Were overweight or obese.
  • Did not have diagnosed heart disease or cancer.
  • May have diagnosed type-2 diabetes. Some studies selected participants that had diagnosed type 2 diabetes. Other studies excluded those patients.

The studies were of 3 types:

  • Short-term: Participants in these studies followed their assigned diets for 3 to <12 months.
  • Long-term: Participants in these studies followed their assigned diets for >12 to 24 months.
  • Short-term with maintenance: Participants in these studies followed their assigned diets for 3 months followed by a 9-month maintenance phase.

What Is The Truth About Low Carb Diets?

The TruthAll the studies included in the Cochrane Collaboration’s meta-analysis randomly assigned overweight participants to a low carbohydrate diet (carbohydrates = <40% of calories) or to a “normal carbohydrate” diet (carbohydrates = 45-65% of calories) with the same degree of caloric restriction.

If low carb diets have any benefit in terms of weight loss, improving blood sugar control, or reducing heart disease risk, these are the kind of studies that are required to validate that claim.

This is what the Cochrane Collaboration’s meta-analysis showed.

When they analyzed studies done with overweight participants without type 2 diabetes:

  • Weight loss was not significantly different between low carb and normal carb diets in short-term studies (3 to <12 months), long-term studies (>12 to 24 months), and short-term studies followed by a 9-month maintenance period.
  • There was also no significant difference in the effect of low carb and normal carb diets on the reduction in diastolic blood pressure and LDL cholesterol.

Since diabetics have trouble controlling blood sugar, you might expect that type 2 diabetics would respond better to low carb diets. However, when they analyzed studies done with overweight participants who had type 2 diabetes:

  • Weight loss was also not significantly different on low carb and normal carb diets.
  • There was no significant difference in the effect of low carb and normal carb diets on the reduction in diastolic blood pressure, LDL cholesterol, and hemoglobin A1c, a measure of blood sugar control.

Of course, the reason Cochrane Collaboration analyses are so valuable is they also analyze the strength of the studies that were included in their analysis.

You may remember in my article two weeks ago, I reported on the Cochrane Collaboration’s report supporting the claim that omega-3 supplementation reduces pre-term births. In that report they said that the studies included in their analysis were high quality. Therefore, they said their report was definitive and no more studies were needed.

This analysis was different. The authors of this Cochrane Collaboration report said that the published studies on this topic were of moderate quality. This means their conclusion is very likely to be true, but further research could have an impact on it.

What Does This Study Mean For You?

confusionIf you are a bit confused by the preceding section, I understand. That was a lot of information to take in. Let me give you the Cliff Notes version.

In short, this Cochrane Collaboration Report concluded:

  • Low carb diets (<40% of calories from carbohydrates) are no better than diets with normal carbohydrate content (45-65% of calories from carbohydrates) with respect to weight loss, reduction in heart disease risk factors, and blood sugar control. Dr. Strangelove has been misleading you again.
  • This finding is equally true for people with and without type 2 diabetes. This calls into question the claim that people with type 2 diabetes will do better on a low carb diet.
  • The published studies on this topic were of moderate quality. This means their conclusion is very likely to be true, but further research could have an impact on it.

If you are thinking this study can’t be true because low carb diets work for you, that is because you are comparing low carb diets to your customary diet, probably the typical American diet.

  • Remember that any whole food diet that eliminates sodas and processed foods and restricts the foods you eat will cause you to lose weight. Whole food keto and vegan diets work equally well short-term compared to the typical American diet.
  • And any diet that allows you to lose weight improves heart health parameters and blood sugar control.

If you are thinking about the blogs, books, and videos you have seen extolling the virtues of low carb diets, remember that the Dr. Strangeloves of the world only select studies comparing low carb diets to the typical American diet to support their claims.

  • The studies included in this Cochrane Collaboration report randomly assigned participants to the low carb and normal carb diets and followed them for 3 to 24 months.
    • Both diets were whole food diets designed by dietitians.
    • Both diets reduced caloric intake to the same extent.

What about the claims that low carb diets are better for your long-term health? There are very few studies on that topic. Here are two:

  • At the 6.4-year mark a recent study reported that the group with the lowest carbohydrate intake had an increased risk of premature death – 32% for overall mortality, 50% for cardiovascular mortality, 51% for cerebrovascular mortality, and 36% for cancer mortality. I will analyze this study in a future issue of “Health Tips From The Professor”.
  • At the 20-year mark a series of studies reported that:
    • Women consuming a meat-based low carb diet for 20 years gained just as much weight and had just as high risk of heart disease and diabetes as women consuming a high carbohydrate, low fat diet.
    • However, women consuming a plant-based low carb diet for 20 years gained less weight and had reduced risk of developing heart disease and diabetes as women consuming a high carbohydrate, low fat diet.

My recommendation is to avoid low-carb diets. They have no short-term benefits when compared to a healthy diet that does not eliminate food groups. And they may be bad for you in the long run. Your best bet is a whole food diet that includes all food groups but eliminates sodas, sweets, and processed foods.

However, if you are committed to a low carb diet, my recommendation is to choose the low-carb version of the Mediterranean diet. It is likely to be healthy long term.

The Bottom Line 

The Cochrane Collaboration, the gold standard of evidence-based medicine, recently issued a report that evaluated the claims made for low carb diets.

All the studies analyzed in the Cochrane Collaboration’s report randomly assigned overweight participants to a low carbohydrate diet (carbohydrates = <40% of calories) or to a “normal carbohydrate” diet (carbohydrates = 45-65% of calories) with the same degree of caloric restriction.

If low carb diets have any benefit in terms of weight loss, improving blood sugar control, or reducing heart disease risk, these are the kind of studies that are required to validate that claim.

The Cochrane Collaboration Report concluded:

  • Low carb diets (<40% of calories from carbohydrates) are no better than diets with normal carbohydrate content (45-65% of calories from carbohydrates) with respect to weight loss, reduction in heart disease risk factors, and blood sugar control.
  • This is equally true for people with and without type 2 diabetes.
  • The published studies on this topic were of moderate quality. This means their conclusion is very likely to be true, but further research could have an impact on it.

My recommendation is to avoid low carb diets. They have no short-term benefits when compared to a healthy diet that does not eliminate food groups. And they may be bad for you in the long run. Your best bet is a whole food diet that includes all food groups but eliminates sodas, sweets, and processed foods.

However, if you are committed to a low carb diet, my recommendation is to choose the low carb version of the Mediterranean diet. It is likely to be healthy long term.

For more details on the study and what it means 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.

Which Diets Are Best In 2022?

Which Diet Should You Choose?

Author: Dr. Stephen Chaney

Emoticon-BadMany of you started 2022 with goals of losing weight and/or improving your health. In many cases, that involved choosing a new diet. That was only a month ago, but it probably feels like an eternity.

For many of you the “bloom” has gone off the new diet you started so enthusiastically in January.

  • Perhaps the diet isn’t working as well as advertised…
  • Perhaps the diet is too restrictive. You are finding it hard to stick with…
  • Perhaps you are always hungry or constantly fighting food cravings…
  • Perhaps you are starting to wonder whether there is a better diet than the one you chose in January…
  • Perhaps you are wondering whether the diet you chose is the wrong one for you…

If you are rethinking your diet, you might want to know which diets the experts recommend. Unfortunately, that’s not as easy as it sounds. The diet world has become just as divided as the political world.

Fortunately, you have an impartial resource. Each year US News & World Report invites a panel of experts with different points of view to evaluate popular diets. They then combine the input from all the experts into rankings of the diets in various categories.

If you are still searching for your ideal diet, I will summarize the US News & World Report’s “Best Diets In 2022”. For the full report, click on this link.

How Was This Report Created?

Expert PanelUS News & World Report recruited panel of 27 nationally recognized experts in diet, nutrition, obesity, food psychology, diabetes, and heart disease to review the 40 most popular diets.  The panel is not the same each year. Some experts are rotated off the panel, and others are added. The experts rate each diet in seven categories:

  • How easy it is to follow.
  • Its ability to produce short-term weight loss.
  • Its ability to produce long-term weight loss.
  • its nutritional completeness.
  • Its safety.
  • Its potential for preventing and managing diabetes.

 

  • Its potential for preventing and managing heart disease.

They converted the experts’ ratings to scores 5 (highest) to 1 (lowest). They then used these scores to construct nine sets of Best Diets rankings:

  • Best Diets Overall combines panelists’ ratings in all seven categories. However, all categories were not equally weighted. Short-term and long-term weight loss were combined, with long-term ratings getting twice the weight. Why? A diet’s true test is whether it can be sustained for years. And safety was double counted because no diet should be dangerous.
  • Best Commercial Diets uses the same approach to rank 15 structured diet programs that require a participation fee or promote the use of branded food or nutritional products.
  • Best Weight-Loss Diets was generated by combining short-term and long-term weight-loss ratings, weighting both equally. Some dieters want to drop pounds fast, while others, looking years ahead, are aiming for slow and steady. Equal weighting accepts both goals as worthy.
  • Best Diabetes Diets is based on averaged diabetes ratings.
  • Best Heart-Healthy Diets uses averaged heart-health ratings.
  • Best Diets for Healthy Eating combines nutritional completeness and safety ratings, giving twice the weight to safety. A healthy diet should provide sufficient calories and not fall seriously short on important nutrients or entire food groups.
  • Easiest Diets to Follow represents panelists’ averaged judgments about each diet’s taste appeal, ease of initial adjustment, ability to keep dieters from feeling hungry and imposition of special requirements.
  • Best Plant-Based Diets uses the same approach as Best Diets Overall to rank 12 plans that emphasize minimally processed foods from plants.
  • Best Fast Weight-Loss Diets is based on short-term weight-loss ratings.

Which Diets Are Best In 2022?

Are you ready? If this were an awards program I would be saying “Envelop please” and would open the envelop slowly to build suspense.

However, I am not going to do that. Here are the top 5 and bottom 5 diets in each category (If you would like to see where your favorite diet ranked, click on this link). [Note: I excluded commercial diets from this review.]

Best Diets Overall 

The Top 5: 

#1: Mediterranean Diet. The Mediterranean diet has been ranked #1 for 5 consecutive years.

#2: DASH Diet (This diet was designed to keep blood pressure under control, but you can also think of it as an Americanized version of the Mediterranean diet.)

#3: Flexitarian Diet (A flexible semi-vegetarian diet).

#4: MIND Diet (This diet is a combination of Mediterranean and DASH but is specifically designed to reduce cognitive decline as we age.)

#5: The TLC Diet (This diet was designed by the NIH to promote heart health.)

The Bottom 5: 

#36: Whole 30 Diet (A whole food, restrictive diet, designed for a 30-day jump start to weight loss. It was not designed for long-term use).

#37: Modified Keto Diet (A slightly less restrictive version of the Keto Diet).

#38: Keto Diet (A high protein, high fat, very low carb diet designed to achieve ketosis).

#39: Dukan Diet (High protein, low carb, low fat diet).

#40: GAPS Diet (A diet designed to improve gut health).

Best Weight-Loss Diets

The Top 5: Weight Loss

#1: Flexitarian Diet

#2: Volumetrics Diet (A diet based on the caloric density of foods).

#3: Vegan Diet (A diet that only allows plant foods).

#4: Mayo Clinic Diet (A diet designed to establish lifelong healthy eating habits).

#5: Ornish Diet (A whole food, semi-vegetarian diet designed to promote heart health).

The Bottom 5: 

#36: Fertility Diet (A diet designed to improve fertility, but the experts were skeptical that it would increase your chances of becoming pregnant)

#37: Whole 30 Diet

#38: Alkaline Diet (A diet designed to make your blood more alkaline, but the experts were skeptical about that claim)

#39: AIP Diet (A diet designed for people with autoimmune diseases)

#40: GAPS Diet

Best Diabetes Diets

The Top 5: 

#1: Mediterranean Diet

#2: Flexitarian Diet

#3: Vegan Diet

#4: Mayo Clinic Diet

#5: DASH Diet

The Bottom 5: 

#36: Alkaline Diet

#37: Dukan Diet

#38: GAPS Diet

#39: Sirtfood Diet (a very low calorie, fad diet that emphasizes plant foods rich in sirtuins)

#40: Whole 30 Diet

Best Heart-Healthy Diets 

strong heartThe Top 5: 

#1: Mediterranean Diet

#2: Ornish Diet

#3: DASH Diet

#4: Flexitarian Diet

#5: TLC Diet

#6: Vegan Diet

The Bottom 5: 

#36: Keto Diet

#37: AIP Diet

#38: Whole 30 Diet

#39: Modified Keto Diet

#40: Dukan Diet

Best Diets for Healthy Eating

The Top 5: 

#1: Mediterranean Diet

#2: DASH Diet

#3: Flexitarian Diet

#4: MIND Diet

#5: TLC Diet

The Bottom 5: 

#36: Raw Food Diet

#37: Atkins Diet

#38: Dukan Diet

#39: Modified Keto Diet

#40: Keto Diet 

Easiest Diets to Follow

The Top 5: Easy

#1: Mediterranean Diet

#2: Flexitarian Diet

#3: Fertility Diet

#4: MIND Diet

#5: DASH Diet

The Bottom 5: 

#36: Modified Keto Diet

#37: Keto Diet

#38: Whole 30 Diet

#39: GAPS Diet

#40: Raw Foods Diet 

Best Fast Weight-Loss Diets

The Top 5 (Excluding Commercial Diets): 

#1: Atkins Diet

#2: Biggest Loser Diet

#3: Keto Diet

#4: Raw Food Diet

#5: Vegan Diet

The Bottom 5 

#36: Dr. Weil’s Anti-Inflammatory Diet

#37: The Fertility Diet

#38: AIP Diet

#39: Alkaline Diet

#40: Gaps Diet

Which Diets Are Best For Rapid Weight Loss?

Happy woman on scaleThere are 3 take-home lessons from the rapid weight loss category:

1) If you are looking for rapid weight loss, any whole food restrictive diet will do. The top 5 diets are very different. For example, the keto and vegan diets are polar opposites, yet they both are in the top 5 for rapid weight loss.

  • The Atkins and keto diets are meat heavy, low carb diets. They restrict fruits, some vegetables, grains, and most legumes.
  • The Biggest Loser diet relies on restrictive meal plan and exercise programs.
  • The restrictions of the raw food diet are obvious.
  • The vegan diet is a very low-fat diet that eliminates meat, dairy, eggs, and animal fats.
  • I did not include commercial diets that rated high on this list, but they are all restrictive in one way or another.

2) We should ask what happens when we get tired of restrictive diets and add back some of your favorite foods.

  • If you lose weight on a vegan diet and add back some of your favorite foods, you might end up with a semi-vegetarian diet. This is a healthy diet that can help you maintain your weight loss.
  • If you lose weight on the Atkins or keto diets and add back some of your favorite foods, you end up with the typical American diet – one that is high in both fat and carbs. This is not a recipe for long-term success.

3) Don’t pay too much attention to the bottom 5 diets. None of them were designed with weight loss in mind.

Which Diet Should You Choose?

Food ChoicesWith rapid weight loss out of the way, let’s get back to the question, “Which Diet Should You Choose?” My recommendations are:

1) Choose a diet that fits your needs. That is one of the things I like best about the US News & World Report ratings. The diets are categorized. If your main concern is diabetes, choose one of the top diets in that category. If your main concern is heart health… You get the point.

2) Choose diets that are healthy and associated with long term weight loss. If that is your goal, you will notice that primarily plant-based diets top these lists. Meat-based, low carb diets like Atkins and keto are near the bottom of the lists.

3) Choose diets that are easy to follow. The less-restrictive primarily plant-based diets top this list – diets like Mediterranean, DASH, MIND, and flexitarian.

4) Choose diets that fit your lifestyle and dietary preferences. For example, if you don’t like fish and olive oil, you will probably do much better with the DASH or flexitarian diet than with the Mediterranean diet.

5) In case you were wondering, intermittent fasting ranked 26-30 and the Paleo diet ranked 26-33 on most of the list – not the worst diets, but a long way from the best. If you have a favorite diet I didn’t mention, check the US News website to find where it is ranked.

6) Finally, focus on what you have to gain, rather than on foods you have to give up.

  • On the minus side, none of the diets include sodas, junk foods, and highly processed foods. These foods should go on your “No-No” list. Sweets should be occasional treats and only as part of a healthy meal. Meat, especially red meat, should become a garnish rather than a main course.
  • On the plus side, primarily plant-based diets offer a cornucopia of delicious plant foods you probably didn’t even know existed. Plus, for any of the top-rated plant-based diets, there are websites and books full of mouth-watering recipes. Be adventurous.

The Bottom Line 

For many of you the “bloom” has gone off the new diet you started so enthusiastically in January. If you are rethinking your diet, you might want to know which diets the experts recommend. Unfortunately, that’s not as easy as it sounds. The diet world has become just as divided as the political world.

Fortunately, you have an impartial resource. Each year US News & World Report invites a panel of experts with different points of view to evaluate popular diets. They then combine the input from all the experts into rankings of the diets in various categories. In the article above I summarize the US News & World Report’s “Best Diets In 2022”.

There are probably two questions at the top of your list.

#1: Which diets are best for rapid weight loss? Here are some general principles:

  • If you are looking for rapid weight loss, any whole food restrictive diet will do.
  • We should ask what happens when we get tired of restrictive diets and add back some of our favorite foods.
  • Long term weight loss is possible if you transition to a healthy diet after you have lost the weight.

#2: Which diet should you choose? Here the principles are:

  • Choose a diet that fits your needs.
  • Choose diets that are healthy and associated with long term weight loss.
  • Choose diets that are easy to follow.
  • Choose diets that fit your lifestyle and dietary preferences.
  • Finally, focus on what you have to gain, rather than on foods you have to give up.

For more details on the diet that is best 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.

Which Diet Is Best?

Tips For Loosing Weight And Keeping It Off

Author: Dr. Stephen Chaney

Diet season starts in just a few days! Like millions of Americans, you will probably be setting 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 what to avoid and…
  • 6 tips on what to look for…

…when you are choosing the best diet for you.

What Should You Avoid When Choosing The Best Diet?

AvoidEndorsements.

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 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.

MagicI 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.

What Should You Look For In Choosing The Best Diet?

Skeptic1) 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.

If you 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 31st 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 Losing Weight And Keeping It 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 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, low fat 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 low-carb version of the Mediterranean diet.
    • 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 in the coming year, you are probably asking, “Which Diet Is Best?” In this issue of “Health Tips From The Professor” I give you:

  • 4 tips on what 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.

 

 

Is The Keto Diet Best For Endurance Exercise?

Where Do Food Myths Come From?

ketogenic dietI don’t need to tell you that the keto diet is popular right now. It is touted for weight loss, mental sharpness, and improved health. I discuss the accuracy of those claims in my book, “Slaying the Food Myths”.

Perhaps more surprising has been the adoption of the keto diet by so many endurance athletes. As I point out in my book, there is a kernel of truth for that idea. Fats and ketone bodies are a very efficient energy source for low to moderate intensity exercise, and we have a virtually unlimited source of stored fat that can be converted to ketone bodies.

However, I always add this caveat, “The keto diet is perfect for endurance exercise – as long as you don’t care how fast you get there”. That is because high intensity exercise requires muscle glycogen stores, which come from the carbohydrates we eat. When you cut carbs from the diet, you deplete your glycogen stores.

And, if you are running a marathon and you want to sprint to the finish line, you will need those muscle glycogen stores. Or, if you are in a cycling event and you want to power up a mountain, you will need those glycogen stores.

Of course, you are probably asking, “Why do so many endurance athletes swear by the keto diet?” There is a dirty little secret behind athlete endorsements. I’m not talking about the money that top athletes get paid for endorsements, although that is also a problem.

I’m talking about the testimonials you hear from your friend who runs marathons or your personal trainer. Unfortunately, testimonials from athletes are notoriously unreliable. The problem is that the placebo effect approaches 70% for athletes.

Competitive athletes are strong willed. If they think a diet or sports nutrition product will help them, they will themselves to a higher level of performance. And this happens subconsciously. They aren’t even aware that their mind is influencing their performance.

So, just because your favorite athlete endorses the keto diet doesn’t mean it is the perfect diet for you. Testimonials can be very misleading.

The important question to ask is, “Do clinical studies support the keto diet as the best diet for endurance exercise?” But, before I answer that question, let me frame the question by asking. “Where do food myths come from?” because the belief that keto diets are best for endurance exercise is a classic food myth.

Where Do Food Myths Come From?

I discussed this question at length in my book, “Slaying The Food Myths”. Let me summarize it briefly here.

Secrets Only Scientists Know: First you need to know the secrets only scientists know. Here are the top 2:

#1: Scientists design their studies to disprove previous studies. There is no glory for being the 10th person to confirm the existing paradigm. The glory comes from being the first to show the existing paradigm might be wrong. While this may seem to be a contrary approach, it is actually the strength of the scientific method.

However, it means that there will be published clinical studies on both sides of every issue.

#2: Every study has its flaws. There is no perfect study.

This is why the scientific community doesn’t base their recommendations on 2 or 3 published studies. We wait until there are 10 to 20 good quality studies and base our recommendations on what 90% of them show.

Now, let me contrast the scientific approach with how food myths are born.

Where Do Food Myths Come From? Food myths usually originate on blogs or websites. Often the articles are written by people with no scientific credentials. But some of them are written by doctors (I will call them Dr. Strangelove to “protect the guilty”). The articles they write have these things in common:

cherry picking studies

  • The articles are based on the biases of the author. No effort is made to look at the other side of the story.
  • The authors “cherry pick” studies that support their bias and ignore studies that contradict them.
  • They use scientific-sounding mumbo jumbo to make their hypothesis sound credible.
  • Their articles are usually spectacular. For example, they say things like, “A particular diet, food, or supplement will either cure you or kill you”, and/or “The medical community is hiding the truth from you.”
  • They never let the facts get in the way of a good story.

Since the idea sounds credible it is picked up by other blogs and websites without any fact checking (social media at its worst). Once it has been repeated often enough, it becomes generally accepted as true. It becomes a food myth. From that point on, studies that disprove the myth are often ignored.

How do you know whether a common belief is true, or just another myth? The only way to be sure is to take a balanced look at all the clinical studies, not just the studies that support the belief.

That is what the authors of a recent review paper (CP Bailey and E Hennessy, Journal of the international Society of Sports Nutrition, 17, Article number: 33, 2020) did for the belief that the keto diet is the best diet for endurance exercise.

Is The Keto Diet Best For Endurance Exercise?

CyclistsBefore I discuss the findings of the review article, there are two things you should know:

#1: There is little scientific research on the effectiveness of the keto diet on endurance exercise. After an exhaustive search of the literature, the authors were only able to find 7 published studies on the topic.

#2:Most sports nutrition studies are of poor quality. In general, they are very small studies, are of short duration, and do not use common test procedures to measure a successful outcome. These studies on keto diets were no different. For example:

    • The number of subjects in these studies ranged from 5 to 29 (average = 14).
    • The duration of time on the diet in these studies ranged from 3 weeks to 12 weeks (average = 5 weeks).
    • Tests used to measure the effectiveness of specific diets on endurance exercise were VO2max (the maximum amount of oxygen you can utilize during exercise), Time to exhaustion (how long you can exercise before you are exhausted), Rating of perceived exertion (feeling of fatigue at the end of the exercise), Race time (time required to complete an event), and Peak power output during the event.
    • Four studies used a treadmill to simulate endurance exercise. The other three used a stationary bike.
    • Five of the studies compared the keto diet to a high carbohydrate diet. Two studies used the keto diet only.

The results were all over the place:

Question Mark

  • Two studies reported an increase in VO2max for both the keto diet and the high carbohydrate diet. One study reported a decrease in VO2max for both diets. The other studies reported no change in VO2max. In short, there was no difference between the diets for VO2max.
  • One study reported a decrease in race time for the high carbohydrate diet and a non-significant increase in race time for the keto diet. Two other studies reported no effect of either diet on race time. In short, one study suggested the high carbohydrate diet was more effective at shortening race time. The other two studies found no effect of either diet.
  • Two studies showed an increase in time to exhaustion for both diets. One study showed a decrease in time to exhaustion for the keto diet (participants got tired more quickly). That study did not include the high carbohydrate diet for comparison. In short, there was no clear difference between the two diets for time to exhaustion.
  • One study showed that the group on the keto diet reported a higher rating of perceived exertion (were more tired) at the end of the endurance event than the group on the high carbohydrate diet. Another study found no difference between the two diets. In short, one study suggested the high carbohydrate diet was better with respect to perceived exertion (tiredness) at the end of the endurance event. Another study found no difference between the two diets.
  • One study reported that peak power was significantly greater for the group on the keto diet than the group on the high carbohydrate diet. One of the studies with the keto group reported that peak power decreased for 4 out of 5 subjects on the keto diet. In short, one study suggested that the keto diet was more effective at increasing peak power than the high carbohydrate diet. Another study suggested the keto diet decreased peak power.

The authors concluded: “When compared to a high carbohydrate diet, there are mixed findings for the effect of the keto diet on endurance performance…The limited number of published studies point to a need for more research in this field.” I would add that we need larger, better designed studies, with common measures of exercise performance.

What Does This Mean For You?

confusionYou may be wondering why I even bothered to talk about such poor-quality studies and a review that could not provide a definitive answer. In fact, that is exactly my point.

This is characteristic of the kind of “evidence” that Dr. Strangelove and his buddies present to support whatever food myth they are featuring on their website. They don’t know how to distinguish good studies from bad studies, and they “cherry pick” only the studies that support their food myth.

So, if you believe that the keto diet is best for endurance exercise, you can “cherry pick” the one published clinical study that supports your belief. You just need to ignore the other 6 published studies.

And, if you believe that a high carbohydrate diet is better for endurance exercise than the keto diet, you can “cherry pick” two clinical studies that support your belief. You just need to ignore the other 5 published clinical studies.

None of the studies are high-quality studies, and the effect of either diet on endurance exercise in these studies is miniscule.

In short, there is no convincing evidence that the keto diet is best for endurance exercise. Or, put another way, we do not have enough evidence to elevate that belief from a food myth to a recommendation we can confidently make for an endurance athlete.

The Bottom Line

A recent publication conducted an impartial review of the evidence for and against the popular belief that a keto diet is the best diet for endurance exercise. The review found only 7 poor-quality studies on this topic in the scientific literature, and the results of those studies were all over the map.

  • One study reported the keto diet was better than a high carbohydrate diet for endurance exercise.
  • Two studies reported that the high carbohydrate diet was better.
  • The other 4 studies were inconclusive.
  • None of the studies found a significant effect on endurance performance by either diet.

So, if you believe that the keto diet is best for endurance exercise, you can “cherry pick” the one published clinical study that supports your belief. You just need to ignore the other 6 published studies.

And, if you believe that a high carbohydrate diet is better for endurance exercise than the keto diet, you can “cherry pick” two clinical studies that support your belief. You just need to ignore the other 5 published clinical studies.

In short, there is no convincing evidence that the keto diet is best for endurance exercise. Or, put another way, we do not have enough evidence to elevate that belief from a food myth to a recommendation we can confidently make for an endurance athlete.

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.

Health Tips From The Professor