Can Gut Bacteria Make You Fat?

bacteria

bacteria

Gut Bacteria, Diet and Obesity

Author: Dr. Stephen Chaney

 

 

Can gut bacteria make you fat? It has been known for some time that the types of bacteria found in the intestines of obese people are different than those found in the intestines of lean individuals. But no one really knew the significance, if any, of that observation. Did obesity favor certain types of intestinal bacteria, or did certain types of intestinal bacteria favor obesity?

Obese individuals are often insulin resistant, and insulin resistance can cause higher sugar levels in the blood, urine and intestine. So it was easy to assume that obesity simply favored the growth of different types of bacteria in the intestine. However, recent studies have suggested that certain types of bacteria in our intestines may actually cause obesity.

Can Gut Bacteria Make You Fat?

For example, one study (Vijay-Kumar et al, Science, 328: 228-231, 2010) compared a strain of mice that are genetically predisposed to obesity with wild type (genetically lean) mice. They first looked at the intestinal bacteria. It turned out that the obese mice and lean mice had the same differences in intestinal bacteria that obese and lean humans have. And just like obese humans the obese mice ate more, displayed insulin resistance, and had elevated levels of triglycerides, cholesterol and blood sugar (They were pre-diabetic).

The investigators then decided to test the hypothesis that the particular bacterial strains found in the intestines of genetically obese mice might be causing their insulin resistance and obesity.

In the first experiment they killed off the intestinal bacteria in the genetically obese mice by putting high dose antibiotics in their food. Depleting the intestinal bacteria created some health problems for the mice, but it completely prevented the insulin resistance, overeating and obesity normally observed with this strain of mice.

In the second experiment they sterilized the intestines of the genetically lean mice and then colonized their intestines with intestinal bacteria from the genetically obese mice. When they did this, the genetically lean mice developed many of the characteristics of the genetically obese mice including insulin resistance, overeating, obesity and hyperglycemia.

insulin resistanceIn short, when their guts became colonized with bacteria from obese mice, the genetically lean mice became overweight and developed diabetes. Based on these experiments and other studies the scientists hypothesized that the wrong kinds of intestinal bacteria can make a significant contribution to insulin resistance, which in turn can lead to overeating and obesity. In short, they concluded that bad gut bacteria may make you fat.

The Battle of The Bacteria

In a second study (Walker et al, Science, 341: 1079-1089, 2013) the intestines of germ free mice were colonized with gut bacteria from lean and obese humans. The results were essentially the same as in the first study. That is, the mice who received gut bacteria from lean humans stayed lean and those who received gut bacteria from obese humans became obese.

But then the investigators asked two really interesting questions:

1) If you mixed the two types of bacteria, which one would win “the battle of the bacteria”?

For this experiment they took mice that had received gut bacteria from lean humans and mice that had received gut bacteria from obese humans and put them in the same cage. It turns out that since mice eat each other’s poop, they pick up each other’s intestinal bacteria. (No, I am not suggesting that you…)

The results of this experiment were (envelop please): The “lean” bacteria won out. They became the predominant bacteria in the intestines of all of the mice in the cage. Furthermore, none of the mice became obese – even the ones that had originally been inoculated with gut bacteria from obese humans.

2) Are the types of bacteria in the intestine influenced by diet?

In the previous experiment the mice were eating standard mouse chow – which is pretty healthy if you are a mouse. So the investigators decided to ask what would happen if they ate foods that were similar to really good and really bad human diets. They devised two types of diets for the mice – one that was high in fresh fruits & vegetable and low in fat (the good diet) and one that was high in fat and low in fresh fruits and vegetables (the bad diet).

On the good diet, the results were the same as in the previous experiment. On the bad diet the “lean” bacteria never grew in the intestines of the mice inoculated with bacteria from obese humans and those mice went on to become obese.

This study confirmed that the wrong kind of gut bacteria can cause obesity, but it also showed that diet can influence the type of bacteria that can grow in the intestine – something I talked about in an earlier issue of “Health Tips From the Professor”  Our Gut Bacteria Are What We Eat.

The Bottom Line

1) Does this mean that you should rush out and buy some probiotics (good bacteria) as part of your weight loss strategy? The simple answer is no. That would be premature. These studies were performed in mice. Although similar results have been reported in humans (for example, Jumpertz et al, Am. J. Clin. Nutr., 94: 58-65, 2011), those studies are very preliminary at present. In addition, genetics and diet obviously played a role in the results. In short, we are a long way from knowing to what extent intestinal bacteria might contribute to obesity in humans.

2) However, there are many very good reasons to make sure that you supply friendly bacteria to your intestinal track on a regular basis. For example, we know that bad bacteria in your intestine can compromise your immune system, convert foods that you eat to cancer causing chemicals, and cause chronic inflammation – which contributes to a number of major diseases.  Can gut bacteria make you fat?  We can’t yet say whether good bugs will help keep you slim, but we do know that they can help keep you healthy.

3) Finally, while we can’t yet say whether probiotic supplements can help you lose weight, it is becoming increasing clear that healthy diets (low fat, high fiber diets with lots of fresh fruits and vegetables) support the type of intestinal bacteria that can make you slim. This is yet one more reason why a healthy diet is so important if you want to stay slim and healthy.

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.

Our Gut Bacteria Are What We Eat

We Grow What We Eat

Author: Dr. Stephen Chaney

BacteriaThe subtitle of this week’s “Health Tips From the Professor” is “We Grow What We Eat”.

No, this is not about each of us starting a backyard garden and literally growing what we eat – although that would probably be a good idea for most of us. I’m actually talking about the bacteria that we “grow” in our intestine.

Most of you probably already know about the concept of “good” and “bad” intestinal bacteria.

Evidence suggests that the “bad” bacteria and yeast in our intestine can cause all sorts of adverse health effects:

  • There is mounting evidence that they can compromise our immune system.
  • There is also evidence that they can create a “leaky gut” (you can think of this as knocking holes in our intestinal wall that allow partially digested foods to enter the circulation where they can trigger inflammation and auto-immune responses).
  • There is some evidence that they can affect brain function and our moods.
  • They appear to convert the foods that we eat into cancer causing chemicals which can be absorbed into the bloodstream.
  • Studies in mice even suggest that they can make us fat.

The list goes on and on…

The “good bacteria” are thought to crowd out the “bad” bacteria and prevent many of the health problems they cause.

In case you’re thinking that it seems a bit far-fetched to think that our intestinal bacteria could affect our health, let me remind you that we have about 100 trillion bacteria in our intestine compared to about 10 trillion cells in our body. They outnumber us 10 to 1.

For years we have thought of “bad” bacteria and yeast as originating from undercooked, spoiled or poorly washed foods that we eat and the “good” bacteria as originating from foods like yogurt and probiotic supplements.

But most of us have not thought that the kinds of foods we choose to eat on a daily basis can affect the kinds of bacteria we “grow” in our intestine – until now. You’ve heard for years that “We are what we eat”. Well it now appears that we also “grow what we eat”. I’m referring to a recent study by G. D. Wu et al (Science, 334: 105-108, 2011).

Our Gut Bacteria Are What We Eat

I’m going to get a bit technical here (Don’t worry. There won’t be a quiz). Scientists refer to the population of bacteria in our intestines as our “microbiome”. Previous studies have shown that people from all over the world tend to have one of two distinct microbiomes (populations of bacteria) in their intestines – Bacteroides or Prevotella. [Again, don’t let the specialized scientific terminology scare you. These are just the names scientists have given to these two distinctive populations of intestinal bacteria].

What this study showed was that people who habitually consumed high-fat/low-fiber diets (diets containing predominantly animal protein and saturated fats) tended to have the Bacteroides bacteria in their intestine, while people who habitually consumed low-fat/high-fiber diets (diets that are primarily plant based and are high in carbohydrate and low in meat and dairy) tended to have the Prevotella bacteria in their intestine. And surprisingly this appears to be independent of sex, weight and nationality.

Is This Important?

The research defining these two distinct microbiomes (populations of intestinal bacteria) and showing that they are influenced by what we eat is very new. At this point in time we know relatively little about the health benefits and risks associated with the Bacteroides and Prevotella microbiomes.

For example:

  • Most of the studies on the health effects of “bad intestinal bacteria” were based on the identification of one or two “bad bacteria” in the gut – not on the hundreds of bacterial species found in the Bacteroides microbiome. So we can’t say for sure that the Bacteriodes microbiome found in people with diets high in animal protein and saturated fats will cause the same health problems as the “bad bacteria”. Nor do we know for sure how important a role the Bacteriodes microbiome plays in the health consequences of consuming that kind of diet.
  • Similarly, many of studies on the health benefits of “good intestinal bacteria” have been based on probiotic supplements containing one or two bacterial species – not the hundreds of bacterial species found in the Prevotella microbiome. So we can’t really say if probiotics or even the Prevotella microbiome will convey the same health benefits seen in populations who consume vegetarian diets.

However, now that do we know that we “grow what we eat” there are numerous studies ongoing to define the benefits and risks associated with each type of bacterial population.

For example, I shared a study with you recently which shows that the intestinal bacteria in people who eat a lot of animal protein convert carnitine (which is also found in meat) to a compound called TMAO, which may increase the risk of heart attacks, and that the conversion of carnitine to TMAO does not occur in people who consume a vegetarian diet ( see “Does Carnitine Increase Heart Disease Risk”)

Stay tuned! I’ll keep you updated as more information becomes available.

The Bottom Line:

Most of the studies I report on are ones that you can act on right away. This one is different. This study introduces a whole new concept – one that raises as many questions as it answers. This makes us ask those “what if” questions.

1)     Previous studies have shown that most people have one of two different kinds of microbiomes (populations of bacteria) in their intestines. This study showed that diets high in animal protein and fat favored one kind of intestinal microbiome, while diets low in fat and high in fiber from fruits & vegetables favored another type of intestinal microbiome.

2)     With a few exceptions we don’t know yet how important a role these intestinal microbiomes play in determining the health consequences of different diets. However, because our intestinal bacteria outnumber the cells in our body by 10:1, it is tempting to ask “What if?”

3)     We also don’t yet know the extent to which probiotics (either from foods or supplements) can overcome the effects of a bad diet on our intestinal microbiome, but it is tempting to ask “What if?”

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.

Can Diet Alter Your Genetic Destiny?

Disease Is Not Inevitable

Author: Dr. Stephen Chaney

Bad GenesMany people seem to have the attitude that if obesity [or cancer, heart disease or diabetes] runs in their family, it is their destiny. They can’t really do anything about it, so why even try?

Most of us in the field of nutrition have felt for years that nothing could be further from the truth. But our belief was based on individual cases, not on solid science. That is no longer the case.

Recent scientific advances have given us solid proof that it is possible to alter our genetic destiny. A family predisposition to diabetes, for example, no longer dooms us to the same fate.

I’m not talking about something like the discredited Blood Type Diet. I’m talking about real science. Let me start by giving you an overview of the latest scientific advances.

Can Diet Alter Your Genetic Destiny?

The answer to this question is YES, and that answer lies in a relatively new scientific specialty called nutrigenomics – the interaction between nutrition and genetics. There are three ways in which nutrition and genetics interact:

1)     Your genetic makeup can influence your nutrient requirements.

The best characterized example of this is methylene tetrahydrofolate reductase (MTHFR) deficiency.  MTHFR deficiency increases the requirement for folic acid and is associated with neural tube defects and other neurological disorders, dementia, colon cancer & leukemia.

In spite of what some blogs and supplement manufacturers would have you believe, supplementation with around 400 IU of folic acid is usually sufficient to overcome the consequences of MTHFR deficiency. 5-methylene tetrahydrofolate (also sold as methyl folate or 5-methyl folate) offers no advantage in absorption, bioavailability or physiological activity (Clinical Pharmacokinetics, 49: 535-548, 2010; American Journal of Clinical Nutrition, 79: 473-478, 2004).

This is just one example. There are hundreds of other genetic variations that influence nutrient requirements – some known and some yet unknown.

2)     A healthy diet can reduce your genetic predisposition for disease.

This perhaps the one that is easiest to understand. For conceptual purposes let us suppose that your genetic makeup were associated with high levels of inflammation. That would predispose you to heart disease, cancer and many other diseases. However, a diet rich in anti-inflammatory nutrients could reduce your risk of those diseases.

This is just a hypothetical example. I’ll give some specific examples in the paragraphs below.

3)     Diet can actually alter your genes.

This is perhaps the most interesting scientific advance in recent years. We used to think that genes couldn’t be changed. What you inherited was what you got.

Now we know that both DNA and the proteins that coat the DNA can be modified, and those modifications alter how those genes are expressed. More importantly, we now know that those modifications can be inherited.

Perhaps the best characterized chemical modification of both DNA and proteins is something called methylation. Methylation influences gene expression and is, in turn, influenced by nutrients in the diet like folic acid, vitamin B12, vitamin B6, choline and the amino acid methionine.

Again this is just the “tip of the iceberg”. We are learning more about how diet can alter our genes every day.

Examples Of How Diet Can Alter Genetic Predisposition

Mature Man - Heart Attack Heart Disease

  • Perhaps the most impressive recent study is one that looked at the effect of diet on 20,000 people who had a genetic predisposition to heart disease (PLOS Medicine, October 2011, doi/10.1371/journal.pmed.1001106).

These people all had a genetic variant 9p21 that causes a 2 fold increased risk of heart attack. The study showed that a diet rich in fruits, vegetables and nuts reduced their risk of heart attack to that of the general population.

  • Another study, the Heart Outcomes Prevention Evaluation (HOPE) study (Diabetes Care, 27: 2767, 2004; Arteriosclerosis, Thrombosis and Vascular Biology, 24: 136, 2008), looked at genetic variations in the haptoglobin gene that influence cardiovascular risk. The haptoglobin 2-2 genotype increases oxidative damage to the arterial wall, which significantly increases the risk of cardiovascular disease.

When the authors of this study looked at the effect of vitamin E, they found that it significantly decreased heart attacks and cardiovascular deaths in people with the haptoglobin 2-2 genotype, but not in people with other haptoglobin geneotypes.

  • There was also a study called the ISOHEART study (American Journal of Clinical Nutrition, 82: 1260-1268, 2005; American Journal of Clinical Nutrition, 83: 592-600, 2006) that looked at a particular genetic variation in the estrogen receptor which increases inflammation and decreases levels of HDL. As you might expect, this genotype significantly increases cardiovascular risk.

Soy isoflavones significantly decreased inflammation and increased HDL levels in this population group. But they had no    effect on inflammation or HDL levels in people with other genotypes affecting the estrogen reception.

To put this in perspective, these studies are fundamentally different from other studies you have heard about regarding nutritional interventions and heart disease risks. Those studies were looking at the effect of diet or supplementation in the general population.

These studies are looking at the effect of diet or supplementation in people who were genetically predisposed to heart disease. These studies show that genetic predisposition [to heart disease] does not have to be your destiny. You can change the outcome!

Cancer

  • A healthy diet (characterized by high intakes of vegetables, fruits, whole grain products and low intakes of refined grain products) compared with the standard American diet (characterized by high intakes of refined grain products, desserts, sweets and processed meats) results in a pattern of gene expression that is associated with lower risk of cancer.  (Nutrition Journal, 2013 12:24).
  • A healthy lifestyle (low fat diet, stress management and exercise) in men with prostate cancer causes downregulation of genes associated with tumor growth (PNAS, 105: 8369-8374).
  • Sulforaphane, a nutrient found in broccoli, turns on genes that suppress cancer.

Diabetes

  • A study reported at the 2013 meeting of the European Association for the Study of Diabetes showed that regular exercise activated genes associated with a lower risk of type 2 diabetes

Cellular Stress Response

  • A diet rich in antioxidant fruits and vegetables activates the cellular stress response genes that protect us from DNA damage, inflammation and reactive oxygen species (BMC Medicine, 2010 8:54).
  • Resveratrol, a nutrient found in grape skins and red wine, activates genes associated with DNA repair and combating reactive oxygen species while it reduces the activity of genes associated with inflammation, increased blood pressure and cholesterol production.

To put these last three examples (cancer, diabetes and cellular stress response) in perspective, they show that diet and supplementation can alter gene expression – and that those alterations are likely to decrease disease risk.

Obesity

  • Finally, an animal study suggests that maternal obesity may increase the risk of obesity in the offspring by increasing their taste preference for foods with lots of sugar and fats (Endocrinology, 151: 475-464, 2010).

The Bottom Line:

The science of nutrigenomics tells us that diet and genetics interact in some important ways:

1)     Your genetic makeup can influence your requirement for certain nutrients.

    • For example, methylene tetrahydrofolate reductase (MTHFR) deficiency increases your requirement for folic acid.
    • Contrary to what many blogs would have you believe, folic acid is just as effective as 5-methylene tetrahydrofolate (also sold as methyl folate or 5-methyl folate) at correcting MTHFR deficiency.

2)     Healthy diet and lifestyle can overcome genetic predisposition to certain diseases. The best established example at present is for people genetically predisposed to heart disease, but preliminary evidence suggests that the risk of other diseases such as diabetes and cancer are altered by your diet.

3)     Diet can actually alter gene expression – for better or worse depending on your diet. Those alterations not only affect your health, but they may affect your children’s health as well.

4)     Nutrigenomics is a young science and many of the individual studies should be considered preliminary. However, the scientific backing is become stronger every day for what many experts in the field have believed for years.

“Your genes do not have to be your destiny. Healthy diet and lifestyle can overcome a genetic predisposition to many diseases.”

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

Does Obesity Begin In Kindergarten?

Is Obesity Caused By Bad Genes Or Bad Lifestyle?

 Author: Dr. Stephen Chaney

 In past issues of “Health Tips From the Professor” I have shared some common sense weight loss tips. But what if it is all for naught? What if there is nothing you can do about your weight?

Fat ChildYou may have seen the headlines suggesting that obesity in kindergarten is a very strong predictor of obesity later in life. If so, you are probably wondering what that means for your kids or grandkids – and what it means for you. You are probably asking questions like:

  • Should you be worrying about that your toddler’s baby fat?
  • What can you do as parents and grandparents to protect the ones you love from a lifetime of obesity and all of the health challenges that involves?
  • Is there anything you can do about overweight and obesity? Are some people just fated to be obese from childhood on?

What Does the Study Actually Show?

This was a very well done study. It followed 7738 children of all socioeconomic classes who were enrolled in kindergarten (mean age 5.6) in the US in 1998 and followed them through the 8th grade (mean age 14.1) (Cunningham et al, New England Journal of Medicine, 370: 403-411, 2014).

When the children entered kindergarten, 12.4% of them were obese, and another 14.9% of them were overweight. By the time they reached the 8th grade 20.8% were obese and 17% were overweight. Those results didn’t make the headlines. They are similar to many previous studies.

The results that made the headlines were:

  • Overweight 5 year olds were 4 times more likely to become obese by age 14 than normal weight 5 year olds.
  • 87% of obese 8th graders (14 year olds) had a body mass index above the 50th percentile in kindergarten, and 75% had a body mass index above the 70th percentile.
  • Only 13% of overweight 8th graders had been normal weight (<50th percentile) in kindergarten, and only 13% of the normal weight 8th graders had been overweight in kindergarten.

These results are fully consistent with earlier studies showing that overweight toddlers are likely to become overweight teens, and overweight teens are likely to become overweight adults. What was unique about this study (and generated the headlines) was the precision of the statistics.

Does Obesity Begin In Kindergarten?

The answer to that question is clearly yes. However, the more important question is what message we, as responsible health advocates, should be sharing with the general public. Let me break that down to some of the most important questions that you are probably asking.

Is Obesity Caused By Bad Genes Or Bad Lifestyle?

Bad GenesTaken on face value, the results of this study might seem to suggest that genetics is the primary cause of obesity. However, if that is the message we convey to the public, it is likely to simply fuel the perception that most overweight individuals are genetically destined to be obese. There is nothing they can do about it. So, why even bother trying?

However, the authors of the study also noted that the percentage of children aged 6 to 11 who are above the 95% percentile of weight has increased 4-fold between 1963 and 2000. Genetics does not change in a mere 37 years (37 generations maybe). That 4-fold increase in severe childhood obesity is clearly driven by lifestyle changes over the past 30 or 40 years.

While nobody knows the exact percentages, a reasonable interpretation of recent research in this area might be:

  • 10-15% of us are genetically destined to be obese. There is little we can do to change our weight, but a healthy lifestyle can significantly reduce our risk of disease.
  • 10-15% of us are genetically predestined to be lean no matter what we eat (Yes. Your suspicions are true). Once again, lifestyle has relatively little influence on our weight, but a healthy lifestyle can significantly reduce our risk of disease.
  • The other 70-80% of us are genetically predisposed to become obese if we adapt the typical American lifestyle. For most of us lifestyle choices can make a big difference in our weight as well as our health.

So the answer to this question is BOTH. For most of us, obesity is caused by bad genes AND bad lifestyle.

When Should We Intervene?

You probably already know that any extra fat cells we develop in childhood never go away. They are always with us, looking for those extra calories they can store as fat.

This study suggests that by the time we are in kindergarten, the die may already be cast. Those extra fat cells may have already developed.

And, for many people, the time to intervene may be even sooner. This study also showed that birth weight plays an important role as well. Children who weighed 9 pounds or more at birth were 2-fold more likely to be obese in kindergarten than children who weighed less than 9 pounds at birth.

Once again, a small percentage of overweight babies is due to genetics, but it is lifestyle choices during pregnancy that lead to the majority of overweight babies.

The authors of the study noted that most public health initiatives (school lunch programs, lifestyle education programs, etc.) are targeted at school aged children. The authors went on to say that by then it may be too late to have any significant effect on the incidence of obesity in our children.

They suggested that we need to place a stronger emphasis on influencing lifestyle changes that affect the weight of babies at birth and are likely to influence whether or not they become obese by the time they reach kindergarten.

That’s not the realm of public health policy. That’s our responsibility.

What Should We Do?

If You Are Pregnant:

  • The old adage “You are eating for two” was never true.
  • Aim for an extra 150 calories during the 1st trimester, 300 during the 2nd and 3rd trimesters (That’s 1 or 2 servings of healthy foods).
  • Aim for little or no weight gain during the 1st trimester and a total of 20-26 pounds during the last two trimesters (a bit less if you are overweight).

If You Have a Young Child Who Is Overweight:

  • Don’t restrict calories. Restricting calories can stunt growth and interfere with normal mental and physical development.
  • Encourage your kids to exercise rather than watching TV and playing video games. You may need to set the example, and that’s a good thing for you as well as for them.
  • Provide your kids with a healthy diet. For most kids, that means more fruits and vegetables and less sugary beverages, fruit juices, and processed snack foods. That may simply mean that you don’t bring those kinds of foods into your house. Again, that would probably be a good thing for everyone in the family.

I know some of you are saying “My kids won’t eat healthy stuff”. Let me give you my take on that.

When I was a kid, my mom had a pretty simple policy. If I didn’t like what she cooked, I didn’t have to eat it. I could simply wait until the next meal – when she would be serving the same kinds of healthy foods again.

I got the message pretty quick. It wasn’t eat healthy or eat junk food. It was eat healthy or go hungry. I decided early on that healthy was better than hungry.

Now, let me step down from my soapbox and summarize.

The Bottom Line:

1)     The latest research suggests that if a child is overweight by kindergarten, they are likely to be overweight for the rest of their lives. So if you want to spare your kids and grandkids  from a lifetime of obesity, you want to intervene early.

2)     A small percentage of those kids are destined to be obese no matter what they do. However, for the vast majority of them obesity can be prevented by a healthy lifestyle.

3)     If you are pregnant, don’t “eat for two”. That is terrible advice. If your pre-pregnancy weight is stable (neither increasing or decreasing), you only need to add a serving or two of healthy foods to your diet during pregnancy. Check with your doctor about the amount of weight gain that is right for you and follow their advice.

4)     If you have a young child who appears to be overweight, don’t restrict their calories. Instead, provide them with healthy food choices and encourage them to exercise.

5)     Finally, if you have been overweight since childhood, don’t despair. For most of us obesity is a combination of genetic predisposition and lifestyle choices. You can’t your genes, but you can change your lifestyle.

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.

Are High Protein Diets Your Secret To Successful Weight Loss?

Do High Protein Diets Reduce Fat And Preserve Muscle?

Author: Dr. Stephen Chaney

Healthy Diet food group, proteins, include meat (chicken or turkAre high protein diets your secret to healthy weight loss? There are lots of diets out there – high fat, low fat, Paleolithic, blood type, exotic juices, magic pills and potions. But recently, high protein diets are getting a lot of press. The word is that they preserve muscle mass and preferentially decrease fat mass.

If high protein diets actually did that, it would be huge because:

  • It’s the fat – not the pounds – that causes most of the health problems.
  • Muscle burns more calories than fat, so preserving muscle mass helps keep your metabolic rate high without dangerous herbs or stimulants – and keeping your metabolic rate high helps prevent both the plateau and yo-yo (weight regain) characteristic of so many diets.
  • When you lose fat and retain muscle you are reshaping your body – and that’s why most people are dieting to begin with.

So let’s look more carefully at the recent study that has been generating all the headlines (Pasiakos et al, The FASEB Journal, 27: 3837-3847, 2013).

The Study Design:

This was a randomized control study with 39 young (21), healthy and fit men and women who were only borderline overweight (BMI = 25). These volunteers were put on a 21 day weight loss program in which calories were reduced by 30% and exercise was increased by 10%. They were divided into 3 groups:

  • One group was assigned a diet containing the RDA for protein (about 14% of calories in this study design).
  • The second group’s diet contained 2X the RDA for protein (28% of calories)
  • The third group’s diet contained 3X the RDA for protein (42% of calories)

In the RDA protein group carbohydrate was 56% of calories, and fat was 30% of calories. In the other two groups the carbohydrate and fat content of the diets was decreased proportionally.

Feet_On_ScaleWhat Did The Study Show?

  • Weight loss (7 pounds in 21 days) was the same on all 3 diets.
  • The high protein (28% and 42%) diets caused almost 2X more fat loss (5 pounds versus 2.8 pounds) than the diet supplying the RDA amount of protein.
  • The high protein (28% and 42%) diets caused 2X less muscle loss (2.1 pounds versus 4.2 pounds) than the diet supplying the RDA amount of protein.
  • In case you didn’t notice, there was no difference in overall results between the 28% (2X the RDA) and 42% (3X the RDA) diets.

Pros And Cons Of The Study:

  • The con is fairly obvious. The participants in this study were all young, healthy and were not seriously overweight. If this were the only study of this type one might seriously question whether the results were applicable to middle aged, overweight coach potatoes. However, there have been several other studies with older, more overweight volunteers that have come to the same conclusion – namely that high protein diets preserve muscle mass and enhance fat loss.
  • The value of this study is that it defines for the first time the upper limit for how much protein is required to preserve muscle mass in a weight loss regimen. 28% of calories is sufficient, and there appear to be no benefit from increasing protein further. I would add the caveat that there are studies suggesting that protein requirements for preserving muscle mass may be greater in adults 50 and older.

The Bottom Line:

1)    Forget the high fat diets, low fat diets, pills and potions. High protein diets (~2X the RDA or 28% of calories) do appear to be the safest, most effective way to preserve muscle mass and enhance fat loss in a weight loss regimen.

2)     That’s not a lot of protein, by the way. The average American consumes almost 2X the RDA for protein on a daily basis. However, it is significantly more protein than the average American consumes when they are trying to lose weight. Salads and carrot sticks are great diet foods, but they don’t contain much protein.

3)     Higher protein intake does not appear to offer any additional benefit – at least in young adults.

4)     Not all high protein diets are created equal. What some people call high protein diets are laden with saturated fats or devoid of carbohydrate. The diet in this study, which is what I recommend, had 43% healthy carbohydrates and 30% healthy fats.

5)    These diets were designed to give 7 pounds of weight loss in 21 days – which is what the experts recommend. There are diets out there promising faster weight loss but they severely restrict calories and/or rely heavily on stimulants, they do not preserve muscle mass, and they often are not safe. In addition they are usually temporary.  I do not recommend them.

6)    This level of protein intake is safe for almost everyone. The major exception would be people with kidney disease, who should always check with their doctor before increasing protein intake. The only other caveat is that protein metabolism creates a lot of nitrogenous waste, so you should drink plenty of water to flush that waste out of your system. But, water is always a good idea.

7)     The high protein diets minimized, but did not completely prevent, muscle loss. Other studies suggest that adding the amino acid leucine to a high protein diet can give 100% retention of muscle mass in a weight loss regimen – but that’s another story for another day.

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

Does Skipping Breakfast Increase Heart Disease Risk?

Should You Eat Breakfast Every Day?

Author: Dr. Stephen Chaney

Mature Man - Heart AttackDoes skipping breakfast actually increase your risk of heart attacks? You’ve probably heard the saying “Eat breakfast like a king, lunch like a prince, and dinner like a pauper”.

You’ve probably also heard that skipping breakfast is associated with increased risk of things like:

 

  • obesity
  • high blood pressure
  • and diabetes

If you believe those associations are true, the latest study showing an association between skipping breakfast and heart disease risk just makes sense. After all, obesity, high blood pressure and diabetes all increase the risk of heart disease.

But, how good is the evidence skipping breakfast actually increases the risk of any of those things?

The evidence for the link between skipping breakfast and heart disease risk:

Let’s start with the current study linking breakfast skipping with heart disease (Cahill et al, Circulation, 128: 337-343, 2013) because its study design is similar to the studies linking breakfast skipping to obesity, high blood pressure and diabetes. This study surveyed the eating habits of 27,000 men (45+ years old) enrolled in the Health Professionals Follow-Up Study in 1992 and followed those men for 16 years.

The results were pretty dramatic. After correcting for other factors that might influence heart disease risk, the men who skipped breakfast were 27% more likely to develop heart disease over the next 16 years than the men who ate breakfast on a daily basis.

As impressive as the association between breakfast and heart disease was, there was an even more impressive association that never made it into the headlines.

There was no association between skipping breakfast and eating late in the evening. However, those men who ate late in the evening were 53% more like to develop heart disease than men who did not.

The pros and cons of the study:

The pros:

1)     The strength of this study is that it is large (27,000 participants), long (16 years) and well designed. The results were statistically very significant.

The cons:

1)     This study only shows associations. It does not prove cause and effect. Having said that, it would be really, really hard to design a placebo controlled study for breakfast versus no breakfast. So cause and effect is almost impossible to prove for this type of comparison.

2)     The study did not ask what kind of breakfast the participants were eating. We don’t know whether the breakfasts were a Danish and coffee, an Egg McMuffin and hash browns  or a high protein smoothie with perhaps some fruit or oatmeal– and, believe me, there is a difference among those three breakfasts!

The Bottom Line:

1)     Eating breakfast is probably a good thing. Yes, the evidence that skipping breakfast increases heart disease risk is circumstantial, but it is also substantial. This is a large, well designed study.

2)     Not all breakfasts are equal. You probably already knew that! I recommend a breakfast with fruit, nuts, whole grains in moderation and lean protein sources.

3)     While this particular study only included men, previous studies suggest that the potential health risks of skipping breakfast are equally strong for women.

4)     Finally, while skipping breakfast grabbed all the headlines, the data suggest that eating late at night is an even stronger predictor of heart disease risk.

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.

Can Soft Drinks Cause Heart Disease?

Put Down That Soda

Author: Dr. Stephen Chaney

 soda-drink-300x181Can Soft Drinks Cause Heart Disease? For today’s “Health Tip” I’m going to paraphrase a quote from your some of your favorite action flicks: “Put down that soda and back away and nobody gets hurt.”

You see, the news about soft drinks keeps getting worse and worse! You’ve probably already heard that soft drink consumption leads to weight gain, pre-diabetes and possibly even diabetes because calories in liquid form do not affect appetite to the same extent as calories in solid form.

Soft Drink Consumption increases the risk of heart attack and stroke in women:

As if that weren’t bad enough, three recent studies suggest that soft drinks consumption is also associated with increased risk of heart attacks and stroke.

The first study looked at sweetened beverage consumption and risk of coronary heart disease in women (Fung et al, Am. J. Clin. Nutr., 89: 1037-1042, 2009).

This study followed 88,520 women enrolled in the Nurses Health Study for 24 years. Consumption of sugar-sweetened beverages (either sodas or non-carbonated sugar-sweetened beverages such as Hawaiian Punch, lemonade and other non-carbonated fruit drinks) was assessed from food-frequency questionnaires administered 7 times during the 24 years. And the total incidence of coronary events (both fatal and non-fatal) was recorded.

The results were striking. When they compared women who consumed as little as one sugar-sweetened beverage per day with women who consumed those beverages less than once per month, the increased risk of coronary heart disease was 23%. And when they compared women who consumed more than two sugar-sweetened beverage per day with women who consumed those beverages less than once per month, the increased risk of coronary heart disease was a whopping 35%.

Sodas are just as harmful for men:

And, in case you guys thought you were off the hook, a study has just been published showing similar results in men (de Koning et al, Circulation, March 12, 2012, Epub ahead of print). This study was a 22 year follow up of 42,883 men enrolled in the Men’s Health Professional study. The study design and results were very similar to the ones obtained previously in the Nurses Health Study except that this study did not distinguish between subjects consuming one sugar sweetened beverage a day and those consuming more than one each day.

When they compared men who consumed one or more sugar sweetened beverage a day to men who never consumed sugar-sweetened beverages, the increased risk of coronary heart disease was 20%.

Diet sodas are just as bad as regular sodas:

 Finally, you may be saying that this information doesn’t apply to you because you only consume diet sodas or artificially sweetened non-carbonated beverages.

Unfortunately, you may not be off the hook either!

Another study published in January 2012 reported that diet soft drink consumption is also associated with increased risk of coronary heart disease – including strokes (Gardener et al, J. Gen. Intern. Med., DOI: 10.1007/sl11606-011-1968-2). This study followed 2564 men and women enrolled in the Northern Manhattan Study for 10 years.

The people in this study who consumed more than one diet soda or artificially sweetened beverage/day were 43% more likely to have a vascular event (heart attack or stroke) then the people consuming less than one diet beverage/month. This study is in line with previous studies showing that diet soda consumption is associated with increased risk of pre-diabetes and type 2 diabetes.

And, as I have pointed out in my previous “Health Tips”, there is no convincing evidence that diet sodas actually help prevent weight gain. Sure there are several published studies showing that when dietitians supervise the diets of the study participants, you can achieve weight loss by substituting diet beverages for sugar containing beverages.

However, two major studies have shown that when you look at free-living populations, consumption of diet beverages is associated with just as much weight gain as consumption of sugar containing beverages (Dhingra et al, Circulation,116: 480-488, 2007; Fowler et al,

Obesity, 16:1894-1900, 2008). Apparently, without a dietitian looking over our shoulder, we manage to make up for those lost calories somewhere else!

The Bottom Line:

So what’s the bottom line for you?

You should be aware that these studies just look at associations – not cause and effect – and they can be skewed by the characteristics of the study populations. For example, there were some striking inconsistencies between the 3 studies I cited that are likely due to differences in the population groups that they sampled. However, despite some differences from one study to the next, the weight of accumulating evidence seems to suggest that sodas – both sugar containing and diet – are really not good for us.

So it’s back to my original advice: “Just put down that soda and nobody gets hurt.” Water is sounding better and better!

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.

Can Obesity Affect Your Sex Drive?

A Big, Fat Problem With Testosterone

Author: Dr. Stephen Chaney

 Obese_Man-300x225Can Obesity Affect Your Sex Drive? While millions of American women are on a diet at any one time, many men just ignore those extra pounds. Things like heart disease, cancer and diabetes seem to be much more distant threats to us. The male ego also allows us to stand in front of a mirror, pot belly and all, and visualize ourselves as we were in our college years.

However, you can’t turn on the TV nowadays without seeing ads for medications to prevent erectile dysfunction and allow you to be ready “when the moment is right.”  Similar ads seem to find their way into our email inbox.  That appears to be a topic of much more relevance to most of us.

What if obesity caused erectile dysfunction? Would that get your attention?

That is why a recent study in the Journal of Clinical Endocrinology and Metabolism should be of great interest to all of us. This study looked at 1700 men of all weights and showed that weight gain of 30 pounds lowered testosterone levels as much as if the men had aged 10 years.

Low testosterone levels in men lead to depression, loss of muscle mass and bone density, feminization, and loss of sexual drive and performance.

The Bottom Line:

So guys, if you are not motivated to lose those extra pounds by how you look or by the increased risk of heart disease, cancer & diabetes, now you have yet another reason to shed those extra pounds.

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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