Truncal Obesity: Can Beer Bellies Really Be Blamed on Overeating?
Truncal obesity has swept our nation. Millions of Americans are overweight and obese. These people are at higher risk for developing a pantheon of medical problems, including but not limited to type 2 diabetes, heart disease, cancer, and stroke.
The natural assumption is to blame our beer bellies and fat thighs on ourselves. We've been taught for decades that, if we don't have the willpower to control what we eat, we will take in more calories than we actually need, and we'll store those excess calories as fat. The only way to rectify the problem is to eat less and/or exercise more.
This whole suite of ideas derives from the 1st law of thermodynamics and constitutes what's known as the Caloric Balance Hypothesis.
The alternative theory, the Lipophilia Hypothesis -- which also derives from the 1st law of thermodynamics -- tells us that physiological factors, such as excess insulin secretion, cause problems like truncal obesity, which in turn causes us to overeat and under exercise.
Caloric Balance tells us that our fat tissue is essentially a piggybank for excess calories.
Lipophilia tells us that our fat tissue is complex and regulated by hormones.
So what does the evidence tell us?
1. With respect to truncal obesity -- a.k.a. the "spare tire" or beer belly -- physiological mechanisms are clearly involved. And what's weird is that we already know what they are! A key agent is an enzyme called lipoprotein lipase (LPL), which insulin regulates and which appears at higher concentrations in the abdominal regions of people with truncal obesity. Essentially, this enzyme helps drive the process by which fat accumulates in the fat tissue of our bellies.
2. Gary Taubes (the science writer who recently re-popularized Lipophilia) has also observed -- and physicians and public health experts will readily admit -- that hormones and enzymes cause growth in our skeletal structure and musculature.
But, as Taubes asks, why do we assume that our fat tissue must somehow psychologically regulated; whereas we admit that muscle and skeletal tissue are physiologically regulated? What makes fat tissue so different from other kinds of tissues in the body? There is no good answer from the Caloric Balance camp.
This contradiction is a big one.
In fact, Taubes' argument can be taken further, revealing just how silly the idea that "calories count" ultimately seems to be. If we overeat, will that give us extra eyes or a second brain or bigger ears? Obviously not. Why then would overeating give us more fat tissue? Why do we assume that "excess" calories go straight to our fat tissue? Why can't they go to our spines, for instance? Conversely, when we create a negative caloric balance -- take in fewer calories than our bodies "need," why does the difference have to be made up by our fat tissue? Why can't the calories come from our hearts or our brains? We assume that fat is a bag that we wear on our bodies. But it's not. It is hormonally active tissue, and it's essential for the regulation of our metabolism. But the Caloric Balance Hypothesis treats fat tissue like it's inanimate, inactive, and irrelevant. Why would obesity researchers assume this, given how much good, proven knowledge we have about fat tissue metabolism?
Remember: we ultimately think obesity is a behavioral problem -- and not a physiological problem -- because of our conviction in the idea that calories "count."