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.

Should I Avoid Whole Grains?

Will Whole Grains Kill Me?

Whole GrainsIt seems like just yesterday that health experts all agreed that whole grains were good for us. After all:

  • They are a good source of fiber, B vitamins, vitamin E, and the minerals magnesium, iron, zinc, manganese, and selenium.
  • Their fiber fills you up, so you are less likely to overeat. This helps with weight control.
  • Their fiber also supports the growth of friendly bacteria in your gut.

In fact, the USDA still recommends that half of the grains we eat should be whole grains. And, outside experts, not influenced by the food industry, feel this recommendation is too low. They feel most of the grains we eat should be whole grains. Foods made from refined grains should be considered as only occasional treats.

Then the low-carb craze came along. Diets like Paleo and Keto were telling you to avoid all grains, even whole grains. Even worse, Dr. Strangelove and his colleagues were telling you whole grains contained something called lectins that were bad for you. Suddenly, whole grains went from being heroes to being villains.

You are probably asking, “Should I avoid whole grains?” What is the truth? Perhaps the best way to resolve this debate is to ask, how healthy are people who consume whole grains for many years? This week I share a recent study (G Zong et al, Circulation, 133: 2370-2380, 2016) that answers that very question.

How Was The Study Done?

This study was a meta-analysis of 14 clinical trials that:

  • Enrolled a total of 786,076 participants.
  • Obtained a detailed diet history at baseline.
  • Followed the participants for an average of 15 years (range = 6-28 years).
  • Determined the effect of whole grain consumption on the risk of death from heart disease, cancer, and all causes.

Will Whole Grains Kill Me?

deadDr. Strangelove and his colleagues are claiming that whole grains cause inflammation, which increases your risk of heart disease and cancer. Heart disease and cancer are the leading causes of death in this country. In fact, according to the CDC, heart disease and cancer accounted for 44% of all deaths in the US in 2017.

Therefore, if Dr. Strangelove and his colleagues were correct, consumption of whole grains should increase the risk of deaths due to heart disease and cancer – and increase the risk of death due to all causes.

That is not what this study showed.

When the highest whole grain intake (5 servings/day) was compared with the lowest whole grain intake (0 servings/day), whole grain consumption reduced the risk of death from:

  • Heart disease by 18%.
  • Cancer by 12%.
  • All causes by 16%.

Furthermore, the effect of whole grains on mortality showed an inverse dose response. Simply put, the more thumbs upwhole grains people consumed, the lower the risk of deaths from heart disease, cancer, and all causes.

However, the dose response was not linear. Simply going from 0 servings of whole grains to one serving of whole grains reduced the risk of death from.

  • Heart disease by 9%.
  • Cancer by 5%.
  • All causes by 7%.

The authors concluded: “Whole grain consumption was inversely associated with mortality in a dose-response manner, and the association with cardiovascular mortality was particularly strong and robust. These observations endorse current dietary guidelines that recommend increasing whole grain intake to replace refined grains to facilitate long-term health and to help prevent premature death.”

The authors went on to say: “Low-carbohydrate diets that ignore the health benefits of whole grain foods should be adopted with caution because they have been linked to higher cardiovascular risk and mortality.”

Should I Avoid Whole Grains?

Question MarkAs for the original question, “Should I avoid whole grains?”, the answer appears to be a clear, “No”.

The strengths of this study include the large number of participants (786,076) and the demonstration of a clear dose-response relationship between whole grain intake and reduced mortality.

This study is also consistent with several other studies that show whole grain consumption is associated with a lower risk of heart disease, diabetes, cancer – and appears to lead to a longer, healthier life.

In short, it appears that Dr. Strangelove and the low-carb enthusiasts are wrong. Whole grains aren’t something to avoid. They reduce the risk of heart disease, diabetes, and cancer. And they reduce the risk of premature death. We should be eating more whole grains, not less.

However, the authors did point out that this study has some weaknesses:

  • It is an association study, which does not prove cause and effect.
  • Study participants who consumed more whole grains also tended to consume more fruits and vegetables – and less red meat, sodas, and highly processed foods.

However, I would argue the second point is a strength, not a weakness. We need to give up the idea that certain foods or food groups are “heroes” or “villains”. We know that primarily plant-based diets like the Mediterranean and DASH diets are incredibly healthy. Does it really matter how much of those health benefits come from whole grains and how much comes from fruits and vegetables?

The Bottom Line

Dr. Strangelove and low-carb enthusiasts have been telling us we should avoid all grains, including whole grains. Is that good advice?

If Dr. Strangelove and his colleagues were correct, consumption of whole grains should increase the risk of deaths due to the top two killer diseases, heart disease and cancer. Furthermore, because heart disease and cancer account for 44% of all deaths in this country, whole grain consumption should also increase the risk of death due to all causes.

A recent study showed the exact opposite. The study showed:

When the highest whole grain intake (5 servings/day) was compared with the lowest whole grain intake (0 servings/day), whole grain consumption reduced the risk of death from:

  • Heart disease by 18%.
  • Cancer by 12%.
  • All causes by 16%.

Furthermore, the effect of whole grains on mortality showed an inverse dose response. Simply put, the more whole grains people consumed, the lower the risk of deaths from heart disease, cancer, and all causes.

However, the dose response was not linear. Simply going from 0 servings of whole grains to one serving of whole grains reduced the risk of death from.

  • Heart disease by 9%.
  • Cancer by 5%.
  • All causes by 7%.

The authors concluded: “Whole grain consumption was inversely associated with mortality in a dose-response manner, and the association with cardiovascular mortality was particularly strong and robust. These observations endorse current dietary guidelines that recommend increasing whole grain intake to replace refined grains to facilitate long-term health and to help prevent premature death.”

The authors went on to say: “Low-carbohydrate diets that ignore the health benefits of whole grain foods should be adopted with caution because they have been linked to higher cardiovascular risk and mortality.”

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.

Which Foods Should I Avoid?

What Is Nutritionism?

In Defense Of FoodRecently, I have been reading Michael Pollan’s book “In Defense of Food”. Yes, I know the book has been around for a long time. Normally I read the scientific literature rather than popular health books. However, in the past few weeks I have had a lot more time to read books, so I decided to read this one.

Some of the things he says are “off the wall”. As he readily admits, he isn’t a scientist or a medical doctor. However, a lot of what he says is “right on”. He echoes many of the things I have been talking about for years. But he does a masterful job of pulling everything together into a framework he calls “nutritionism”.

If you have a chance, I highly recommend that you read his book.

I will briefly summarize his discussion of nutritionism below. I will also share some scientific support for what he is saying. Finally, I will close by sharing what the Bible says on the subject.

What Is Nutritionism?

Low Fat LabelSimply put, nutritionism is the belief that we can understand food solely in terms of its nutritional and chemical constituents and our requirements for them. I use the term “belief” purposely. As Michael Pollan puts it: “As the ‘-ism’ suggests, nutritionism is not a scientific subject, but an ideology.”

What Michael Pollan is referring to is taking food constituents like saturated fats, cholesterol, sugar, carbohydrates, polyunsaturated fats, monounsaturated fats, fiber, antioxidants, and probiotics and labeling them as either “good” or “bad”.

As he points out, that leads to debacles like the creation of margarine as a substitute for butter. Of course, everyone reading this article knows that we subsequently found out that the trans fat in margarine was worse for us than the saturated fat in butter. He offers many other examples like this.

He also points out that the nutritionism concept has given free rein to the food industry to replace whole foods with processed foods that are cholesterol-free, sugar-free, low-fat, low-carb, or high in fiber, omega-3s, etc. He says that these foods are seldom healthier than the foods they replace. I agree.

Finally, he points out that the scientific support for the classification of individual ingredients or foods as “good” or “bad” is weak. That’s because when scientists design a study that removes a chemical constituent or a food from the diet, they have to replace it with something. And what they replace it with determines the outcome of the study. I give some examples of this in the next section.

The essence of Michael Pollan’s message is:

  • The effect of an individual nutrient or chemical constituent on your health depends on the food it is found in. Forget the fancy nutrition labels. Whole foods are almost always healthier than processed foods.
  • The effect of a food or food constituent on your health also depends on your overall diet. We should be thinking about healthy diets rather than the latest “magical” or “forbidden” food.

I will discuss these points below.

Which Foods Should I Avoid?

Question MarkNow, let’s get to the question, “Which Foods Should I Avoid?” If we are talking about whole foods, the short answer is “None”. As I said in my book, “Slaying The Food Myths”, “We have 5 food groups for a reason”.

For example, if we are talking about plant foods, each plant food group:

  • Has a unique blend of vitamins and minerals.
  • Has a unique blend of phytonutrients.
  • Has a unique blend of fiber.
  • Supports the growth of a unique combination of beneficial gut bacteria.
  • Dr Strangelove and his friends are telling you to eliminate whole grains, fruits, and legumes (beans) from your diet. Recent studies suggest that might not be a good idea. Here is one example.

If we are talking about animal foods, each animal food group:

  • Has a unique blend of vitamins and minerals.
  • May have unique components that are important for our health. [Note: This is an active area of research. Theories have been proposed for which components in animal foods may be important for our health, but they have not been confirmed.]
  • Vegan purists will tell you that you have no need for meat and dairy foods. Recent studies suggest otherwise. Here is one example.

With that as background, let’s turn our attention to nutritionism and look at some of science behind claims that certain food components are either good for us or bad for us.

Saturated Fat. Saturated fat is the poster child for nutritionism.lowfat

First, we were told by the American Heart Association and other health organizations that saturated fat was bad for us. Recently Dr. Strangelove and his friends are telling us that saturated fat is good for us. Instead of limiting saturated fat, we should be limiting carbs by cutting out fruits, whole grains, and legumes. Both cite clinical studies to support their claims. How can this be?

Perhaps a little history is in order. When the American Heart Association recommended that we decrease intake of saturated fat, they were envisioning that we would replace it with monounsaturated and polyunsaturated fat in the context of a healthy diet of fruits, vegetables, whole grains, and legumes. That never happened.

Big Food quickly realized that if the American public were to follow the AHA guidelines, it would be disastrous for their bottom line. So, they sprang into action. They mixed sugar, white flour, and a witch’s brew of chemicals to create highly processed, low fat “foods”. Then they told the American public, “Don’t worry. You don’t have to give up your favorite foods. We have created low fat alternatives.”

This is the essence of what Michael Pollan refers to as nutritionism. By marketing their fake foods as low fat Big Food created the halo of health. In fact, Big Food’s fake foods were less healthy than the foods they replaced. Americans got fatter and sicker.

Now let’s look at the conflicting claims that saturated fat is bad for us or good for us. How can clinical studies disagree on such an important question? The answer is simple. It depends on what you replace it with. You need to consider saturated fat intake in the context of the overall diet.

I discussed this in a previous issue of “Health Tips From the Professor”, but let me summarize it briefly here. The American Heart Association tells us that replacing half of the saturated fat in a typical American diet with:

  • Trans fats, increases heart disease risk by 5%.
  • Refined carbohydrates and sugars (the kind of carbohydrates in the typical American Diet), slightly increases heart disease risk.
  • Complex carbohydrates (whole grains, fruits & vegetables), decreases heart disease risk by 9%.
  • Monounsaturated fats (olive oil & peanut oil), decreases heart disease risk by 15%.
  • Polyunsaturated fats (vegetable oils and fish oil), decreases heart disease risk by 25%.
  • Unsaturated fats in the context of a Mediterranean diet, decreases heart disease risk by 45%.

My advice: Saturated fat is neither good for you nor bad for you. A little bit of saturated fat in the context of a healthy diet is fine. A lot of saturated fat in the context of an unhealthy diet is problematic.

fatty steakRed Meat. Is red meat bad for you? Like saturated fat, it depends on the amount of red meat and the overall diet. I covered this in detail in “Slaying The Food Myths”, but let me summarize briefly here:

According to the World Health Organization, red meat is a probable carcinogen. If we look at the postulated mechanisms by which it causes cancer, they can be mostly neutralized by components of various plant foods.

My advice: An 8-ounce steak with fries and a soda is probably bad for you. Three ounces of that same steak in a green salad or stir fry may be good for you.

I should make one other point while I am on the topic. Dr. Strangelove and his friends have been telling you that grass-fed beef is better for you than conventionally raised beef. Once again, that is nutritionism.  Grass-fed beef is lower in saturated fat and high in omega-3s than conventionally raised beef. That may be better for your heart, but it has no effect on the cancer-causing potential of red meat. It doesn’t give the license to eat 8-ounce steaks on a regular basis. You still want to aim for 3-ounces of that grass-fed beef in a green salad or stir fry. 

High-Fructose Corn Syrup. This one seems to be on everyone’s “naughty list”. You are being told to read labels, and if the food has high-fructose corn syrup on the label, put it back on the shelf. But is that good advice?

It turns out that all the studies on the bad effects of high-fructose corn syrup have been done with sodas and highly processed foods. This should be your first clue.

Of course, as soon as high-fructose corn syrup gained its “bad” reputation, Big Food started replacing it with Sugar Comparisons“heathier” sugars. Does that make those foods healthier?

The answer is a clear “No”. Both chemically and biologically, high-fructose corn syrup is identical to sucrose (table sugar), honey, molasses, maple syrup, coconut sugar, date sugar, or grape juice concentrate. Agave sugar is even higher in fructose than high-fructose corn syrup. This is your second clue.

Substituting these sugars for high-fructose corn syrup doesn’t turn sodas and processed foods into health foods. This is nutritionism at its worst.

My advice: Forget reading the label. Forget trying to avoid foods with high-fructose corn syrup. Avoid sodas and processed foods instead.

Sugar. Once the public started to realize that natural sugars in processed foods were just as bad for us as high-fructose corn syrup, sugars became “bad”. We were told to avoid all foods containing sugar in any form. In fact, we were told we needed to become “label detectives” and recognize all the deceptive ways that sugar could be hidden on the label.

Apple With Nutrition LabelI have discussed this in detail in a previous issue of “Health Tips From The Professor”.

Let me just summarize that article with one quote, “It’s not the sugar. It’s the food. There is the same amount and same types of sugar in an 8-ounce soda and a medium apple. Sodas are bad for you, and apples are good for you.” If you are wondering why that is, I have covered it in another issue of “Health Tips From the Professor”.

Before leaving this subject, I should mention that nutritionism has risen its ugly head here as well. Big Food has struck again. They have replaced sugar with a variety of artificial sweeteners.

Once again, nutritionism has failed. Those artificially sweetened sodas and processed foods are no healthier and no more likely to help you keep the weight off than the sugar-sweetened foods they replace. I have covered the science behind that statement in several previous issues of “Health Tips From the Professor”. Here is one example.

My advice: Forget about sugar phobia. You don’t need to become a label detective. Just avoid sodas, sugar-sweetened beverages, and sweet processed foods. Get your sugar in its natural form in fruits and other whole foods.

low carb dietCarbs. Dr. Strangelove and his friends are now telling you that you need to avoid all carbs. That is pure nutritionism. Carbs are neither good nor bad. It depends on the type of carb and what you replace it with.

Once again, clinical studies have given conflicting outcomes. Each side of the carbohydrate debate can provide clinical studies to support their position. How can that be? The answer is simple. It depends on what assumptions went into the design of the clinical studies. I have written several articles on this topic in “Health Tips From the Professor”, but let me give you one example here.

In this example, I looked at two major studies. The PURE (Prospective Urban Rural Epidemiology) study included data from 135,000 participants in 18 countries. In this study, the death rate decreased as the % carbohydrate in the diet decreased. The low-carb enthusiasts were doing a victory dance.

However, it was followed by a second, even larger study. The ARIC (Atherosclerosis Risk In Communities) study included 432,000 participants from even more countries. In this study, the death rate decreased as the % carbohydrate decreased to about 40%. Then a curious thing happened. As the % carbohydrate in the diet decreased further, the death rate increased.

How can you explain this discrepancy? When you examine the PURE study:

  • The % carbohydrate only ranged from 70% to 40%.
  • The data for the PURE study was obtained primarily with third world countries. That is an important distinction because:
    • In those countries, it is primarily the well to do that can afford sodas, processed foods, and meat.
    • The poor subsist on what they can grow and inexpensive staples like beans and rice.
  • Simply put, in the PURE study, the type of carbohydrate changed as well as the amount of carbohydrate.
    • At the highest carbohydrate intakes, a significant percentage of the carbohydrate came from sugar and refined grains.
    • At the lowest carbohydrate intakes, most of the carbohydrate intake came from beans, whole grains, and whatever fruits and vegetables they could grow.

When you examine the ARIC study:how much carbohydrates should we eat aric

  • The % carbohydrate ranged from 70% to 20%.
  • The ARIC study added in data from the US and European countries. That is an important distinction because:
    • Low carb diets like Atkins and Keto are popular in these countries. And those are the diets that fall into the 20-40% carbohydrate range.
    • Most people can afford diets that contain a lot of meat in those countries.
  • Simply put, at the lower end of the scale in the ARIC study, people were eating diets rich in meats and saturated fats and eliminating healthy carbohydrate-containing foods like fruits, whole grains and legumes.

My advice: The lesson here is to avoid simplistic nutritionism thinking and focus on diets rather than on foods. When you do that it is clear that carbs aren’t bad for you, it’s unhealthy carbs that are bad for you.

Which Foods Should I Avoid? By now the answer to the question, “Which Foods Should I Avoid?” is clear. Avoid sodas, sugar-sweetened beverages and processed foods (The term processed foods includes convenience foods, junk foods, and most sweets).

What Does This Mean To You?

Questioning ManNow that we are clear on which foods you should avoid, let’s look at the flip side of the coin. Let’s ask, “Which foods should you include in your diet?

As I said at the beginning of this article, “We have 5 food groups for a reason”. We should consider whole foods from all 5 food groups as healthy.

Of course, each of us is different. We all have foods in some food groups that don’t treat us well. Some of us do better with saturated fats or carbs than others. We need to explore and find the foods and diets that work best for us.

However, whenever we assume one diet is best for everyone, we have crossed the line into nutritionism.

What Does The Bible Say?

Let me start this section by saying that I rely on the Bible for spiritual guidance rather than nutritional guidance. However, as part of our church’s Bible reading plan, I was reading 1 Timothy. A passage from 1 Timothy 4:1-5 leapt out at me. It reinforces the theme of Michael Pollan’s book and seems uniquely applicable to the times we live in.

“The Spirit clearly says that in later times some will abandon the faith and follow deceiving spirits and things taught by demons. Such teachings come through hypocritical liars, whose consciences have been seared as with a hot iron. They…order people to abstain from certain foods, which God created to be received with thanksgiving by those who believe and who know the truth. For everything God created is good, and nothing is to be rejected if it is received with thanksgiving, because it is consecrated by the word of God and prayer.”

Interesting.

The Bottom Line

In this article, I have discussed the concept of “nutritionism” introduced in Michael Pollan’s book “In Defense Of Food”. He defines nutritionism as the belief that we can understand food solely in terms of its nutritional and chemical constituents and our requirements for them.

What Michael Pollan is referring to is taking food constituents like saturated fats, cholesterol, sugar, carbohydrates, polyunsaturated fats, monounsaturated fats, fiber, antioxidants, and probiotics and labeling them as either “good” or “bad”. He points out that when we accept these simplistic labels, we often end up creating foods and diets that are less healthy than the ones we were trying to replace.

At the beginning of the article, I asked the question, “Which Foods Should I Avoid?” I then looked at several foods or food groups we have told to avoid, including saturated fats, red meat, high-fructose corn syrup, sugar, and carbs. When you look at the science behind these recommendations from the lens of nutritionism, you come to two conclusions:

  • We should avoid sodas, sugar-sweetened beverages and processed foods (The term processed foods includes convenience foods, junk foods, and most sweets).
  • Whole foods from all 5 food groups should be considered as healthy.

Of course, each of us is different. We all have foods in some food groups that don’t treat us well. Some of us do better with saturated fats or carbs than others. We need to explore and find the foods and diets that work best for us.

However, whenever we assume one diet is best for everyone, we have crossed the line into nutritionism.

For more details and a bible verse that supports the theme of Michael Pollan’s book and seems uniquely applicable to the times we live in, 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 Ketogenic Diet Safe?

Is The Ketogenic Diet Effective?

Author: Dr. Stephen Chaney

ketogenic dietThe ketogenic diet has been around for a while. It has been used to control epilepsy in children since the 1920s. Nobody is quite sure why it helps control epilepsy, but it does. Once a mainstay of therapy, it is now primarily used as an adjunct to anti-epileptic drugs.

However, recently the ketogenic diet has gone mainstream. It’s no longer just for epilepsy. It has become the latest diet fad. If you believe the claims:

  • Hunger and food cravings will disappear. The pounds will melt away effortlessly and rapidly.
  • You will feel great. You’ll have greater mental focus and increased energy.
  • Physical endurance will increase. You’ll become superhuman.
  • Type 2 diabetes will disappear.
  • Your blood sugar, cholesterol, and triglyceride levels will improve, reducing your risk of developing diabetes and heart disease.

What’s not to like? This sounds like the perfect diet. But, are these claims true? More importantly, is this diet safe?

What Is Ketosis?

what is ketosisKetosis is a natural metabolic adaptation to starvation. To better understand that statement let me start with a little of what I’ll call metabolism 101.

Metabolism 101:

The Fed State: Here’s what happens to the carbohydrate, protein & fat we eat in a meal.

  • Most carbohydrates are converted to blood sugar (glucose), which is utilized in three ways:
    • Most tissues use glucose as their primary energy source in the fed state.
    • Excess glucose is stored as glycogen in muscle and liver.
    • Glycogen stores are limited, so much of the excess glucose is stored as fat.
  • A few tissues such as heart muscle use fat as an energy source. Excess fat is stored.
  • Protein is also used in three ways:
    • Some of it is used to replace and repair the protein components in muscle and other tissues.
    • In conjunction with exercise, protein can be used to increase muscle mass.
    • Excess protein is converted to fat and stored.

The Fasting State: Between meals:

  • Most tissues switch to fats as their primary energy source. Fat stores are utilized to fuel the cells that can use fat.
  • Brain, red blood cells, and a few other tissues still rely solely on glucose as their energy source.
    • Liver glycogen stores are broken down to keep blood glucose levels constant and provide energy for these tissues. (Muscle glycogen stores are reserved for high intensity exercise).
    • As liver glycogen stores are depleted, the body starts breaking down protein and converting it to glucose.

ketogenic diet problems and solutionsStarvation – The Problem: If the fasting state were to continue for more than a few days, we enter what is called starvation. At this point we have a serious problem. Fat stores and carbohydrate stores (liver glycogen) exist for the sole purpose of providing fuel during the fasting state. Protein, however, is unique. There are no separate protein stores in the body. All protein in our body is serving essential functions.

To make matters worse, our brain is metabolically very active. It consumes glucose at an alarming rate. Thus, large amounts of glucose are needed even in the fasting state. If protein continued to be converted to glucose at the same rate as during an overnight fast, our essential protein reserves would rapidly be depleted. Irreversible damage to heart muscle and other essential organs would occur. We would be dead in a few weeks.

Starvation – The Solution: Fortunately, at this point a miraculous adaptation occurs. Our bodies start to convert some of the fat to ketones.

  • All tissues that use fat as an energy source during fasting can also use ketones as an energy source, sometimes with greater efficiency.
  • Over a period of several days, the brain adapts to ketones as its primary energy source. This greatly reduces the depletion of cellular protein to supply blood glucose.
  • However, red blood cells and a few other cells still require glucose as an energy source. Essential protein reserves are still being depleted, but at a far slower pace.
  • With these adaptations, humans can survive months without food if necessary.

There are a few other adaptations that make sense if we think about the dilemma of going long periods without food.

  • Appetite decreases.
  • Metabolic rate decreases, which helps preserve both protein & fat stores.

 

What Is The Ketogenic Diet?

 

ketogenic diet keytonesProponents of the ketogenic diet advocate achieving a permanent state of ketosis without starving yourself. That is achievable because the real trigger for ketosis is low blood sugar, not starvation.

The starting point for the ketogenic diet is low-carb, high-fat diets like Atkins. However, ketogenic diets go beyond traditional low-carb, high-fat diets. They restrict carbohydrates even further to <10% of calories so that a permanent state of ketosis can be achieved. Basically, the ketogenic diet:

  • Eliminates grains and sugars.
  • Eliminates most fruits.
  • Eliminates starchy vegetables (root vegetables, corn, peas, beans, squash & yams).
  • Reduces protein intake. That’s because dietary protein will be converted to glucose when blood glucose levels are low.

You are left with a highly restrictive diet that allows unlimited amounts of fats & some vegetables and moderate amounts of meats, eggs, and cheeses.

The Ketogenic Diet Is Not For Wimps

ketogenic diet tough#1: You have to be committed. As noted above, this is a highly restrictive diet. You will have great difficulty following it when you eat out or are invited to a friend’s house for dinner. You will also have to give up many of your favorite foods.

#2: The transition is rough. Physiological adaptation to the ketogenic diet will take anywhere from a couple of days to a week or two. During that time, you will have to endure some of the following:

  • Headaches, confusion & “brain fog”
  • Fatigue
  • Hunger
  • Lightheadedness and shakiness
  • Leg cramps
  • Constipation
  • Bad breath
  • Heart palpitations

#3: There are no “cheat days”. On most diets, you can have occasional “cheat days” or sneak in some of your favorite foods from time to time. The ketogenic diet is different. A single “cheat day” is enough to take you out of ketosis. If you want to resume the ketogenic diet, you will need to go through the transition period once again.

Is The Ketogenic Diet Effective?

ketogenic diet effectiveWith this background in mind, let’s evaluate the claims made by proponents of the ketogenic diet. I’ll rate them on the “Pinocchio Scale”. “Zero Pinocchios” means they are mostly true. “One Pinocchio” means they are half true. “Two Pinocchios” means they are mostly false.

Zero Pinocchios (Mostly True Claims):

  • Reduced hunger. This is part of the starvation response.
  • Improved mental focus and increased energy. In part, this is simply in contrast to the “brain fog” and fatigue of the transition phase. However, you have also eliminated all foods that can cause blood sugar swings from your diet. Blood sugar swings can affect both mental focus and energy levels.
  • Rapid weight loss. If we focus on short term weight loss, this is true because:
    • A lot of the initial weight loss is water. Glycogen stores retain water. As glycogen stores are depleted, the water is lost along with them.
    • Most people inadvertently reduce their caloric intake on a highly restrictive diet like this. For example, fats are often consumed along with carbohydrate-rich foods (butter with toast, sour cream with potatoes, cream cheese with bagels). While it is easy to say that unlimited consumption of healthy fats is allowed, most people reduce their consumption of fats in the absence of their carbohydrate-rich companions.
    • Note: Proponents of the ketogenic diet will tell you that the weight loss associated with the ketogenic diet is because you are burning fat stores. You will only burn fat stores when dietary fat intake is not sufficient to meet your energy needs. In other words, you burn your fat stores when “calories in” are less than “calories out” – just as with any other diet.
  • Reversal of type 2 diabetes. Because carbohydrates are restricted in this diet, blood sugar and insulin levels will be low. If you are on medications, those will need to be adjusted by your physician.

 

One Pinocchio (Half-True Claims):

  • Improved cholesterol and triglyceride levels. The jury is out on this one. Some studies show an improvement on the ketogenic diet. Other studies show them getting worse.
  • Increased physical endurance. This is only true for low-intensity endurance exercise. It is not true for any exercise or event that requires spurts of high intensity exercise. That’s because:
    • The muscle fibers used for low intensity endurance exercise utilize ketone bodies with high efficiency. That means you can run for miles as long as you don’t care how fast you get there.
    • The muscle fibers used for high-intensity, short-duration exercise cannot adapt to use of ketone bodies because they lack sufficient mitochondria. They require glycogen stores, which are depleted on a ketogenic diet. Even in endurance events like marathons most people want to sprint to the finish line. They won’t be able to do that if they are on a ketogenic diet.

 

Two Pinocchios (Mostly False Claims):

  • ketogenic diet mythsLong term weight loss. Some long-term success has been claimed in a highly controlled clinical setting. However, most studies show:
    • People regain some or most of the weight after 6 months to a year.
    • After 1 or 2 years, there is no difference in weight loss between high-fat/low-carb diets and low-fat/high-carb diets.
    • That’s because:
      • Most people cannot stick to restrictive diets long term, and this diet is very restrictive.
      • Once you go off this diet, even for a short time, your glycogen stores will be replenished and the water weight will return along with the glycogen.
      • The reduction in metabolic rate and the reduction in muscle mass associated with the ketogenic diet make it difficult to keep the weight off long term
  • It is a healthy diet.
    • This is a healthy diet only from the point of view that it eliminates most fast foods and processed foods.
    • However, any diet that eliminates 2 and a half food groups (grains, fruits, and starchy vegetables) is setting you up for long term nutritional deficiencies. It is possible to cover some of those deficiencies with supplementation, but supplements can never provide all the nutrients found in real food.

 

Is The Ketogenic Diet Safe?

ketogenic diet safeFor most people the ketogenic diet is likely to be safe for short periods, maybe even a few months. However, I have grave concerns if the diet is continued long term.

  • I have already mentioned the likelihood this diet will create nutritional deficiencies. Long term, those deficiencies could have severe health consequences.
  • Proponents of the diet recommend that protein intake be limited so that “optimal” ketosis can be achieved. If the dieter is successful at doing that, it will result in a gradual depletion of essential cellular protein reserves as discussed above. Long term, that has the potential to weaken heart muscle, compromise the immune system, and damage essential organs.
  • Ketones can damage the kidneys. In the short term, damage is likely to be minimal as long as plenty of water is consumed. However, long term ketosis could be a significant concern for your kidneys.

I have seen proponents of the ketogenic diet shrug this off as a concern only if protein intake is excessive. They are missing the point. The problem is the ketones, not the protein.

  • Long term ketosis has the potential to cause osteoporosis. That is because the so-called “ketones” are actually organic acids except for the small amount of acetone that gives your breath a fruity smell. Organic acids must be neutralized to keep our body pH in the normal range. There are multiple mechanisms for neutralizing organic acids. One of those mechanisms involves dissolving bone and releasing calcium carbonate into the bloodstream. This slow dissolution of bone will continue for as long as someone is in ketosis.

 

Proponents of the ketogenic diet shrug this off by saying that you never get into ketoacidosis on their diet. Again, they are missing the point. Ketoacidosis simply means that the production of organic acids has become so great that all the body’s mechanisms for neutralizing those acids have become overwhelmed. Ketoacidosis occurs in uncontrolled diabetes and can be deadly. The problem is the slow dissolution of bone during long term ketosis, not a short-term crisis like ketoacidosis.

If you are considering the ketogenic diet for weight loss, my recommendations would be to:

  • Consider other equally effective, but less demanding, weight loss programs. Look for programs that help you preserve muscle mass and teach you healthy eating habits that can be sustained for a lifetime.
  • If you do decide to follow the ketogenic diet, only use it for a short period of time to jump start your weight loss. Then switch to a diet program that has been clinically proven to improve your health long term. Examples would be the Mediterranean diet and the Dash diet.

If you are choosing the ketogenic diet for health reasons, I would recommend the Mediterranean diet or Dash diet instead.

 

The Bottom Line

 

  1. The ketogenic diet is the latest diet fad. I give it a C+ compared to other popular diets.
  2. This is not a diet for wimps.
    • It is a highly restrictive diet
    • The transition period as you adjust to the diet is rough.
    • There are no “cheat days”
  3. Some of the claims made for the ketogenic diet are mostly true, some are half-true, and some are mostly false. I help you sort them out in the article above.
  4. Short term, the diet is probably safe for most people. However, long term I have several concerns.
    • The diet is likely to create nutritional deficiencies. Long term, those deficiencies could have severe health consequences.
    • The diet is likely to gradually deplete essential cellular protein reserves. Long term, that could weaken heart muscle, compromise the immune system, and damage essential organs.
    • The diet has the potential to damage the kidneys.
    • The diet has the potential to cause osteoporosis.
    • The metabolic rationale for those concerns is discussed in the article above.
  5. If you are considering the ketogenic diet for weight loss, my recommendations would be to:
    • Consider other equally effective, but less demanding, weight loss programs. Look for programs that help you preserve muscle mass and teach you healthy eating habits that can be sustained for a lifetime.
    • If you do decide to follow the ketogenic diet, only use it for a short period of time to jump start your weight loss. Then switch to a diet program that has been clinically proven to improve your health long term. Examples would be the Mediterranean diet and the Dash diet.
  6. If you are choosing the ketogenic diet for health reasons, I would recommend the Mediterranean diet or Dash diet instead.

 

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.

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