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

Are Pregnant Women and Children Dangerously Deficient in Omega-3s?

Posted August 13, 2019 by Dr. Steve Chaney

What Is The Omega-3 Status Of The American Population?

Author: Dr. Stephen Chaney

 

pregnant women omega 3 deficient fishIt is no secret that the American population is deficient in omega-3s. Numerous studies have documented that fact. There are many reasons for Americans’ low intake of omega-3s:

  • The high price of omega-3-rich fish.
  • Concerns about sustainability, heavy metal contamination, and/or PCB contamination of omega-3 rich fish.
  • Misleading headlines claiming that omega-3 supplements are worthless and may even do you harm.

Of course, the questions you are asking are probably?

  • How deficient are we?
  • Does it matter?

The latest study (M Thompson et al, Nutrients, 2019, 11: 177, doi: 10.3390/nu11010177) goes a long way towards answering those important questions.

How Was The Study Done?

scientific studyThis study used data on 45,347 Americans who participated in NHANES surveys between 2003 and 2014. (NHANES or National Health and Nutrition Examination Surveys is a program run by the CDC that is designed to assess the health and nutritional status of adults and children living in the United States).

EPA and DHA intake from foods was based on the average of two 24-hour dietary recall interviews. Trained dietary interviewers collected detailed information on all foods and beverages consumed during the past 24 hours.

To assess EPA and DHA intake from supplements study participants were asked what supplements they had taken in the past 30 days, how many days out of 30 they had taken it, and the amount that was taken on those days.

 

What Is The Omega-3 Status Of The American Population?

 

omega 3 statusThe results of the NHANES surveys were shocking.

In terms of total EPA+DHA intake:

  • EPA+DHA intake across all age groups was lower than recommended.
  • Toddlers (ages 1-5), children (ages 6-11), and adolescents (ages 12-19) had lower EPA+DHA intakes than adults (ages 20-55) and seniors (ages > 55).
  • Women had lower EPA+DHA intakes than men.
  • Pregnant women and women of childbearing age did not differ in their EPA+DHA.
  • Pregnant women consumed less fish than women of childbearing age (perhaps because of concerns about heavy metal contamination).
  • Pregnant women consumed more omega-3 supplements.

In terms of EPA+DHA from supplements:

  • Less than 1% of the American population reported using omega-3 supplements.
  • The one exception was pregnant women. 7.3% of pregnant women reported taking an omega-3 supplement.
  • People taking omega-3 supplements had significantly higher EPA+DHA intake than people not taking omega-3 supplements.
  • This was also true for pregnant women. Those taking omega-3 supplements had higher EPA+DHA intake.

Of course, like any clinical study, it has strengths and weaknesses.

The biggest weakness of this study is that omega-3 intake is based on the participants recall of what they ate. The strengths of the study are its size (45,347 participants) and the fact that its estimate of omega-3 intake is consistent with several smaller studies.

 

Are Americans Deficient In Omega-3s?

 

pregnant women omega 3 deficient questionsNow we are ready to answer the questions I posed at the beginning of this article. Let’s start with the first one: “How deficient are we?”

You would think the answer to that question would be easy. It is not. This study provides a precise estimate of American’s omega-3 intake. The problem is there is no consensus as to how much omega-3s we need. There is no RDA for omega-3s.

There are, in fact, three sets of guidelines for how much omega-3s we need, and they disagree.

  • The World Health Organization (WHO) recommendations for EPA+DHA intake range from 100-150 mg/day at ages 2-4 years to 200-500 mg/day for adults.
  • The US National Institute of Medicine (IOM) recommendations for EPA+DHA intake range from 70 mg/day for ages 1-3 to 110 mg/day for adult females and 160 mg/day for adult males.
  • As if that weren’t confusing enough, an international group of experts recently convened for a “Workshop on the Essentiality of and Recommended Dietary Intakes for Omega-6 and Omega-3 Fatty Acids” (Workshop). This group recommended an EPA+DHA intake of 440 mg/day for adults and 520 mg/day for pregnant and lactating women.

Using these recommendations as guidelines, this study reported that:

  • EPA+DHA intake for children 1-5 years old was ~25% of the WHO recommendations and ~40% of IOM recommendations.
  • EPA+DHA intake for children 6-11 years old was ~27% of WHO recommendations and ~40% of IOM recommendations.
  • EPA+DHA intake for adolescents 12-19 years old was ~50% of IOM recommendations (The WHO did not have a separate category for adolescents.
  • EPA+DHA intake for adults 20-55 years old was ~30% of WHO recommendations, and ~65% of IOM recommendations.
  • EPA+DHA intake for seniors >55 years old was 38% of WHO recommendations and 82% of IOM recommendations.
  • EPA+DHA intake for pregnant women was ~20% of Workshop recommendations (The WHO and IOM did not have a separate category for pregnant women).

While the percentage deficiency varied according to the EPA+DHA guidelines used, it is clear from these results that Americans of all age groups are not getting enough omega-3s from their diet.

The authors concluded: “We found omega-3 intakes across all age groups was lower than recommended amounts.”

 

Are Pregnant Women and Young Children Dangerously Deficient In Omega-3s?

 

danger symbolWhile the authors concluded that all age groups were deficient in omega-3s, they were particularly concerned about the omega-3 deficiencies in pregnant women and young children.

The authors said: “Taken together, these findings demonstrate that low omega-3 fatty acid intake is consistent among the US population and could increase the risk for adverse health outcomes, particularly in vulnerable populations (e.g., young children and pregnant women).”

In part, the focus on young children and pregnant women was based on their very low omega-3 intake. With intakes at 20-27% of recommended levels, I would consider these groups to be dangerously deficient in omega-3s.

pregnant women omega 3 deficient pregnancyHowever, the focus on young children and pregnant women was also based on the seriousness of the adverse health outcomes associated with low omega-3 intake in these population groups. This answers the second question I posed at the beginning of this article: “Does it matter?”

According to the authors low intake of EPA and DHA during pregnancy and early childhood is associated with maternal depression, pre-term births, low birth-weight babies, increased risk of allergies and asthma, problems with learning and cognition, and other neurocognitive outcomes.

None of these associations between low omega-3 intake and adverse health outcomes have been proven beyond a shadow of a doubt, but the evidence is strong enough that we should be alarmed by the very low omega-3 intake in pregnant women and young children.

There is, however, a simple solution. The authors of this study concluded: “Individuals taking EPA/DHA containing supplements had significantly elevated intake compared to individuals not taking omega-3 fatty acid-containing supplements or not reporting any supplement use.”

omega 3 supplementsThey went on to say: “As supplement use is associated with increased omega-3 intake, supplementation could be an important source of EPA/DHA, particularly for pregnant women given their lower fish consumption compared to non-pregnant women of childbearing age.”

I agree. Given the low omega-3 intake in these population group and current guidelines for omega-3 intake. I recommend:

  • Pregnant & lactating women (and women of childbearing age who might become pregnant) take an omega-3 supplement providing around 520 mg of EPA+DHA/day.
  • Young children (ages 1-5) take an omega-3 supplement providing around 100 mg of DHA/day.

Of course, this study also confirmed that Americans of all age groups are not getting enough omega-3s from their diet, and low omega-3 intake may increase the risk of heart disease. Furthermore, recent studies have shown that high purity omega-3 supplements may reduce heart disease risk.

You will find my recommendations for omega-3 supplementation for adults in a previous issue of “Health Tips From the Professor.”

 

The Bottom Line

 

The largest study to date (45,347 participants) measured omega-3 intake for Americans of all ages and compared that to current recommendations for omega-3 intake.

The authors of the study concluded:

  • “We found omega-3 intakes across all age groups was lower than recommended amounts.”
  • “Low omega-3 fatty acid intake … could increase the risk for adverse health outcomes, particularly in vulnerable populations (e.g., young children and pregnant women.”

In part, the focus on young children and pregnant women was based on their very low omega-3 intake. With intakes at 20-27% of recommended levels, I would consider these groups to be dangerously deficient in omega-3s.

However, the focus on young children and pregnant women was also based on the seriousness of the adverse health outcomes associated with low omega-3 intake in these population groups.

  • According to the authors low intake of EPA and DHA during pregnancy and early childhood is associated with maternal depression, pre-term births, low birth-weight babies, increased risk of allergies and asthma, problems with learning and cognition, and other neurocognitive outcomes.

There is, however, a simple solution. The authors of this study also concluded:

  • “Individuals taking EPA/DHA containing supplements had significantly elevated intake compared to individuals not taking omega-3 fatty acid-containing supplements or not reporting any supplement use.”
  • “As supplement use is associated with increased omega-3 intake, supplementation could be an important source of EPA/DHA, particularly for pregnant women given their lower fish consumption compared to non-pregnant women of childbearing age.”

For more details on the study and my recommendations for omega-3 supplementation, 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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