More Excuses for Obesity?

There is an ongoing debate about the causes of the obesity epidemic. A recent academic study, described here, reported the following:

A given person, in 2006, eating the same amount of calories, taking in the same quantities of macronutrients like protein and fat, and exercising the same amount as a person of the same age did in 1988 would have a BMI about 2.3 points higher. In other words, people today are about 10 percent heavier than people were in the 1980s, even if they follow the exact same diet and exercise plans.

What may be cause of this observation (assuming it is valid)? We read:

In an interview, Kuk proffered three different factors that might be making harder for adults today to stay thin. 

First, people are exposed to more chemicals, some of which might be weight-gain inducing. Pesticides, flame retardants, and the substances in food packaging might all be altering our hormonal processes and tweaking the way our bodies put on and maintain weight.

Second, the use of prescription drugs has risen dramatically since the ‘70s and ‘80s. Prozac, the first blockbuster SSRI, came out in 1988. Antidepressants are now one of the most commonly prescribed drugs in the U.S., and many of them have been linked to weight gain. 

Finally, Kuk and the other study authors think that the microbiomes of Americans might have somehow changed between the 1980s and now. It’s well known that some types of gut bacteria make a person more prone to weight gain and obesity. Americans are eating more meat than they were a few decades ago, and many animal products are treated with hormones and antibiotics in order to promote growth. All that meat might be changing gut bacteria in ways that are subtle, at first, but add up over time. Dr. Kuk believes the proliferation of artificial sweeteners could also play a role.

Let’s consider these hypotheses (which may or may not eventually be supported by future data).

Diet affects the microbiome; in the article, meat is mentioned.  Other studies, including those in “humanized” mice, have shown that only one day on a “junk food diet” can alter the microbiome, the bacterial colonizing our gut.  Studies in human volunteers have shown the same.  These changes seem to be reversible. Diet is something that we have control over; we can eat less meat, and a healthier and higher-fiber diet enriched in while grains, fruits, and vegetables. Artificial sweeteners can be avoided. Other dietary factors linked to obesity, such as high fructose corn syrup or sugary sodas should be eliminated.

The researchers notes that the use of certain prescription drugs that have weight-gain as a side-effect has “risen dramatically.”  Although some people no doubt require such medications, the sharp increase in antidepressant use suggests the possibility that perhaps they are being over-prescribed and are not always necessary. This is another modifiable risk factor at both the individual and societal level.

Chemical exposure is a factor, one that can be avoided to the extent possible, although their ubiquity makes that difficult.  However, that same ubiquity suggests to us to look closely at the fact that while most Americans are sharing these same exposures, not all are obese/overweight.

What about other hypotheses and/or variables that can be controlled for? Was muscle-fat composition controlled for? If people today have, for original lifestyle reasons, more fat and less muscle than those in past generations, then this would account for less “burning” of calories, since muscle is more metabolically active than fat. So, it is possible people become overweight, with a higher body fat percentage, due to modifiable lifestyle changes, and then find that this change in body composition makes losing weight more difficult. There is the “cause vs. effect” issue here; one bottom line is prevention – it is better not to become overweight to start with, since losing weight will become much more difficult.

There’s an underlying problem with how this study is being presented, which mirrors how “fat gene” studies are also presented: the idea that things are beyond our control, no one is at fault, and we must be accepting of the obesity epidemic.  But, as stated, even if the abovementioned hypotheses are correct, many are modifiable, and it is imperative that these modifications be attempted.

After all, the problem can be looked at academically from another perspective: compare individuals from the same age group, contrasting those of normal weight to those overweight and obese. Let us compare their diet and activity level.  One hypothesis: those of normal weight will have healthier diets, and more activity, than those overweight and obese.

The problem exists and must be dealt with. Eat properly (including less [red] meat and artificial sweeteners. Do not take mind-altering medication unless it is truly necessary. Be more active. Avoid to the extent possible environmental stressors that promote obesity. We need to work together to eliminate as many of those stressors as possible. Do not accept an epidemic destroying the health of individuals and a society.