Are Low Carb Diets Healthy?

Written by Dr. Steve Chaney on . Posted in low carb diet

Can You Eat Low Carb & Live A Long And Healthy Life?

Author: Dr. Stephen Chaney

 

Are low carb diets healthy?

are low carb diets healthyAtkins, Paleo, Keto…It seems like everyone is following a low carb diet nowadays. They are popular, but they are also controversial. At this point you are probably wondering are low carb diets healthy and is there any evidence to support it one way or the other?  I searched the literature to find the answer to that question. The answer is:

Yes, there is evidence that some low carb diets are healthy…

…but, not for the reasons low carb enthusiasts give…

…and, not for the diets they promote.

Let me elaborate.

 

Why Are The Arguments Of Low Carb Enthusiasts Misleading?

are low carb diets healthy enthusiastMost proponents of low carb diets claim they are healthy based on improvements in blood parameters, usually things like lower triglycerides, higher HDL, lower blood glucose and insulin levels, and lower blood pressure. They sometimes claim lower LDL levels and lower levels of inflammation, although clinical studies are inconsistent for the effects of low carb diets on LDL and inflammation. They then go on to extrapolate from these data to claim their diet will reduce the risk of heart disease, diabetes, and other diseases.

These extrapolations are misleading for three reasons:

#1: Most of these comparisons are with the standard American diet. As I have said previously, almost anything is better than the standard American diet.

#2: Most of these studies are short term. The comparisons are generally made during the weight loss phase of these diets or at a time when the dieters have achieved significant weight loss. That is significant because weight loss improves all those parameters. If the comparisons were made during the maintenance phase or after most of the weight had been regained (as it usually is), the results might have been completely different.

#3: These blood parameters are imperfect indicators of disease risk. I find it particularly amusing that low carb proponents downplay the risk of saturated fats by saying that LDL and HDL cholesterol are imperfect indicators of disease risk and then use the same indicators to predict their diet will lower the risk of heart disease.

The only accurate way to determine the effect of a diet on disease risk is to conduct long term studies that measure the health outcomes of the diet. Those studies have been done, but they don’t support popular diets like Atkins, Paleo, or Keto.

 

Are Low Carb Diets Healthy and If So, Which Ones?

which low carb diets are healthyThere are, in fact, several long-term studies showing that low carb diets are healthy, but only if you ditch the animal protein and animal fats, and replace them with vegetable protein and vegetable oils.

For example, a 20-year study of 82,802 women in the Nurses’ Health Study found that women who ate a low-carbohydrate diet that was high in vegetable protein and oils had 30% lower risk of developing heart disease compared to women who ate high-carbohydrate, low-fat diets (T.L. Halton et al, New England Journal of Medicine, 355: 1991-2002, 2006). In contrast, the women who consumed a low-carbohydrate diet that was high in animal protein and fat fared no better than women consuming a high-carbohydrate, low-fat diet.

A follow-up study with the same group of women compared the effect of the same diets over a period of 20 years on the risk of developing type 2 diabetes (T.L. Halton et al, American Journal of Clinical Nutrition, 87: 339-346, 2008 ). The results were very similar. Women consuming a low-carbohydrate diet high in vegetable protein and oils had an 18% decreased risk of developing diabetes. Once again, the women consuming a low-carbohydrate diet high in animal protein and fats had just as high a risk of developing diabetes as women consuming the high-carbohydrate, low-fat diet.

This may have been because women consuming a low-carbohydrate, high animal protein and fat diet gained just as much weight over 20 years as women consuming a high-carbohydrate, low-fat diet. In contrast, women who consumed the low-carbohydrate diet high in vegetable protein and oils gained much less weight. At the end of the 20-year study, they weighed significantly less than the women in the other two groups (T.L. Halton et al, New England Journal of Medicine, 355: 1991-2002, 2006 ). This is not surprising, since we already know that vegetarians weigh less than their meat-eating friends.

However, it does run counter to what the low carb diet promoters have been telling you. They claim their diets help you lose weight. You do lose weight more rapidly on a typical low carb diet, but at the end of a year or two you end up weighing just as much as if you followed a low-fat diet (F.M. Sacks et al, New England Journal of Medicine, 360: 859-873, 2009) .  By the end of 20 years you will have gained significant weight compared to someone following a more plant-based diet (T.L. Halton et al, New England Journal of Medicine, 355: 1991-2002, 2006 ). It appears that the only low carb diet likely to give you permanent weight loss is a low carb vegetarian diet.

This is reinforced by another study showing that consumption of junk foods (potato chips and fries), sodas, processed meats, red meats, butter, sweets & desserts, and refined grains was associated with weight gain over a 4-year period (D. Mozaffarian et al, New England Journal of Medicine, 364: 2392-2404, 2011 ). In contrast, consumption of vegetables, fruits, nuts, whole grains, and yoghurt was associated with weight loss.

It’s not just women. A 20-year study of 40,475 men found that men consuming a low-carbohydrate diet high in animal protein and fat had a 37% increased risk of developing type 2 diabetes (L. de Koning et al, American Journal of Clinical Nutrition, 93: 844-850, 2011 ). In contrast, men consuming a low-carbohydrate diet high in vegetable protein and oils had a 34% decreased risk of developing type 2 diabetes.

 

Other Healthy Low Carb Diets

 

are low carb diets healthy vegetablesI have previously shared evidence that a Mediterranean diet reduces the risk of developing type 2 diabetes. Several recent studies have shown that a low-carbohydrate version of the Mediterranean diet is preferable for managing people who already have diabetes.

For example, one recent study put people who had just developed type 2 diabetes on either the low-carbohydrate Mediterranean diet or the low-fat, calorie-restrict diet usually recommended for overweight patients with diabetes (K. Esposito et al, Annals of Internal Medicine, 151: 306-314, 2009). At the end of 4 years, only 44% of the patients on the low-carbohydrate Mediterranean diet required drug treatment compared to 70% in the low-fat group.

Another entry into the low carb diet category is the eco-Atkins diet. It is a low-carbohydrate vegan diet (I find it amusing to label a diet “Atkins” when it has no meat and no saturated fat). For example, one recent study suggests it is more effective than a low-fat diet at reducing blood lipid levels and reducing blood pressure (D.J.A. Jenkins et al, Archives of Internal Medicine, 169: 1046-1054, 2009 ).

If you want to follow a low carb diet, the low carb Mediterranean and eco-Atkins diets are both healthy diets. You could create your own plant-based low carb diet, but you can find meal plans and recipes for both these diets online.

What Does This Mean For You?

Vegan, vegetarian, and primarily plant-based diets like the Mediterranean diet are all healthy diets. Long-term studies show they decrease your risk of developing heart disease, diabetes, cancer, and other diseases. Long-term studies also show that plant-based low carb diets help keep the pounds off and reduce your risk of heart disease and diabetes.

In contrast, meat-based low carb diets offer no advantage over low fat diets at keeping the pounds off or reducing the risk of heart disease or diabetes. There are no long-term studies on meat-based low carb diets and cancer risk, but we already know that red meat is a probable carcinogen. We also know that plant-based diets decrease your risk of several cancers. In short, there is no long-term evidence that the low-carb, meat-based diets decrease your risk of any disease and some evidence they may increase your risk of disease.

So, are low carb diets healthy?  Yes, if you stop eating animal protein and animal fats and make vegetable protein and oils a part of your diet.

The Bottom Line

 

  • Ignore the claims by proponents of the popular low carb diets that their diets are healthy. Those claims are based on:
    • Comparisons with the standard American diet.  Anything is better.
    • Short term studies when the participants were losing weight.  Any diet looks good during the weight loss phase.
    • Blood parameters (HDL, triglycerides, blood sugar, etc.). These are imperfect measures of long-term health outcomes.
  • Long-term (20-year) studies of the effects of low carb diets on health outcomes have been performed. Those studies show:
    • People following a meat-based low carb diet (one that focuses on animal proteins and animal fats):
      • Gained just as much weight over a 20-year period as people following a low-fat diet.
      • Had the same or greater risk of developing heart disease and diabetes as people following a low-fat diet.
    • People following a plant-based low carb diet (one that focuses on vegetable protein and vegetable oils):
      • Weighed significantly less than the other two groups at the end of 20 years.
      • Had a significantly lower risk of developing heart disease and diabetes than the other two groups.

In summary, vegan, vegetarian, and primarily plant-based diets like the Mediterranean diet are all healthy diets. Long-term studies show they decrease your risk of developing heart disease, diabetes, cancer, and other diseases. Long-term studies also show that plant-based low carb diets help keep the pounds off and reduce your risk of heart disease and diabetes.

In contrast, meat-based low carb diets offer no advantage over low fat diets at keeping the pounds off or reducing the risk of heart disease or diabetes. There are no long-term studies on meat-based low carb diets and cancer risk, but we already know that red meat is a probable carcinogen. We also know that plant-based diets decrease your risk of several cancers. In short, there is no long-term evidence that the low-carb, meat-based diets decrease your risk of any disease and some evidence they may increase your risk of disease.

For more details and the low carb diets I recommend, 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.

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Latest Article

Does Protein Supplement Timing Matter?

Posted May 15, 2018 by Dr. Steve Chaney

How Do You Gain Muscle Mass & Lose Fat Mass?

Author: Dr. Stephen Chaney

 

protein supplement timingMost of what you read about protein supplements on the internet is wrong. That is because most published studies on protein supplements:

  • Are very small
  • Are not double blinded.
    • Both the subjects and the investigators knew who got the protein supplement.
  • Are done by individual companies with their product.
    • You have no idea which ingredients are in their product are responsible for the effects they report.
    • You have no idea how their product compares with other protein products.
    • There is no standardization with respect to the amount or type of protein or the addition of non-protein ingredients.

Because of these limitations there is a lot of misleading information on the benefits of protein supplements timing and maximal benefit. Let’s start by looking at why people use protein supplements. Let’s also look at what is generally accepted as true with respect to the best supplement timing.

There are 4 major reasons people consume protein supplements:

  • Enhance the muscle gain associated with resistance training: In this case, protein supplements are customarily consumed concurrently with the workout.
  • Preserve muscle and accelerate fat loss while on a weight loss diet: In this case, protein supplements are customarily consumed with meals or as meal replacements.
  • Provide a healthier protein source. In this case, protein supplements are customarily consumed with meals in place of meat protein.
  • Prevent muscle loss associated with aging or illness. There is no customary pattern associated with this use of protein supplements.

How good are the data supporting the customary timing of protein supplementation? The answer is: Not very good. The timing is based on a collection of weak studies which do not always agree with each other.

The current study  (J.L. Hudson et al, Nutrition Reviews, 76: 461-468, 2018 ) was designed to fill this void in our knowledge. It is a meta-analysis that compares all reasonably good studies that have looked at the effect of protein supplement timing on weight gain or loss, lean muscle mass gain, fat loss, and the ratio of lean muscle mass to fat mass.

How Was The Study Done?

The authors started by doing a literature search of all studies that met the following criteria:

  • The study was a randomized control trial with parallel design. This means that study contained a control group. It does not mean that the investigators or subjects were blinded with respect to which subjects used a protein supplement and which did not.
  • The subjects were engaged in resistance training.
  • The study lasted 6 weeks or longer.
  • Reliable methods were used to measure body composition (lean muscle mass and fat mass).
  • The subjects were healthy and at least 19 years old.
  • There was no restriction on the food the subjects consumed.

The authors started with 2074 published studies and ended up with 34 that met all their criteria. They then separated the studies into two groups – those in which the protein supplements were used with meals and those in which the protein supplements were used between meals.

Both groups were diverse.

  • Group 1 included subjects who consumed their protein supplement with their meal and those who consumed their protein supplement as a meal replacement.
  • Group 2 included subjects who consumed their protein supplement concurrent with exercise (usually immediately after exercise) and those who consumed their protein supplement at a fixed time of day not associated with exercise.

Does Protein Supplement Timing Matter?

 

protein supplement timing workoutsBecause the individual studies were very diverse in the way they were designed, the authors could not calculate a reliable estimate of how much lean muscle mass was increased or fat mass was decreased. Instead, they calculated the percentage of studies showing an increase in lean muscle mass or a decrease in fat mass.

When the authors compared protein supplements consumed with meals versus protein supplements consumed between meals:

  • Weight gain was observed in 56% of the studies of protein supplementation with meals compared to 72% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • An increase in lean muscle mass was observed in 94% of the studies of protein supplementation with meals compared to 90% of the studies of protein supplementation between meals. In other words, timing of protein supplementation did not matter with respect to increase in muscle mass.
  • A loss of fat mass was observed in 87% of the studies of protein supplementation with meals compared to 59% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • An increase in the ratio of lean muscle mass to fat mass was observed in 100% of the studies of protein supplementation with meals compared to 87% of the studies of protein supplementation between meals. In short, protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean muscle mass to fat mass.

The following seem to suggest protein supplement timing matters:

The authors pointed out that their findings were consistent with previous studies showing that when protein supplements are consumed with a meal they displace some of the calories that otherwise would have been consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors stated that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

The others concluded: “Concurrently with resistance training, consuming protein supplements with meals, rather than between meals, may more effectively promote weight control and reduce fat mass without influencing improvements in lean [muscle] mass.”

What Are The Limitations Of The Study?

Meta-analyses such as this one, are only as good as the studies included in the meta-analysis. Unfortunately, most sports nutrition studies are very weak studies. Thus, this meta-analysis is a perfect example of the “Garbage In: Garbage Out (GI:GO)” phenomenon.

For example, let’s start by looking at what the term “protein supplement” meant.

  • Because the studies were done by individual companies with their product, the protein supplements in this meta-analysis:
    • Included whey, casein, soy, bovine colostrum, rice or combinations of protein sources.
    • Were isolates, concentrates, or hydrolysates.
    • Contained various additions like creatine, amino acids, and carbohydrate.
  • As I discuss in my book, Slaying the Food Myths, previous studies have shown that optimal protein and leucine levels are needed to maximize the increase in muscle mass and decrease in fat mass associated with resistance exercise. However, neither protein nor leucine levels were standardized in the protein supplements included in this meta-analysis.
  • Previous studies have shown that protein supplements that have little effect on blood sugar levels (have a low glycemic index) are more likely to curb appetite. However, glycemic index was not standardized for the protein supplements included in this meta-analysis.

protein supplement timing workout peopleIn short, the conclusions of this study might be true for some protein supplements, but not for others. We have no way of knowing.

We also need to consider the composition of the two groups.

  • Protein supplements used as meal replacements are more likely to decrease weight and fat mass than protein supplements consumed with meals. Yet, both were included in group 1.
  • Some studies suggest that protein supplements consumed concurrent with resistance exercise are more likely to increase muscle mass than protein supplements consumed another time of day. Yet, both are included in group 2. We also have no idea whether the meals with protein supplements in group 1 were consumed shortly after exercise or at an entirely different time of day.

This was the most glaring weakness of the study because it was completely avoidable. The authors could have grouped the studies into categories that made more sense.

In other words, there are multiple weaknesses that limit the predictive power of this study.

What Can We Learn From This Study?

Despite its many limitations, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, most of us are using protein supplements to lose weight or to increase our lean mass to fat mass ratio. Simply put, we are either trying to lean out (shape up) or lose weight. And, we want to lose that weight primarily by getting rid of excess fat. For us, calories do matter. With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

 

The Bottom Line:

 

A recent study looked at the optimal timing of protein supplements consumed by subjects who were engaged in resistance exercise. Specifically, the study compared protein supplements consumed with meals versus protein supplements consumed between meals on weight, lean muscle mass, fat mass, and the ratio of lean muscle mass to fat mass. The study reported:

  • Protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • Timing of protein supplementation did not matter with respect to increase in muscle mass.
  • Protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • Protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean mass to fat mass.

The authors pointed out that their findings were consistent with previous studies showing that when a protein supplement was consumed with a meal it displaces some of the calories that would have been otherwise consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors said that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

As discussed in the article above, the study has major weaknesses. However, despite its many weaknesses, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, for those of us who are using protein supplements to lose weight or to increase our lean mass to fat mass ratio, calories do matter.  With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

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.

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