The Beer Belly: Why Do We Get Fat around the Middle?

KEY POINT: Our fat tissue is not a "trash can" for excess calories; it's a metabolic organ.

We tend to think of our fat as a sort of garbage bag for calories. When we overeat, somehow we just stuff the "extra" calories into our fat tissue. And when we exercise or starve, the fat tissue somehow exudes those extra calories from the beer belly to supply our energy needs, and we grow lean. This is an extremely simplistic view of how fat tissue works, and it is belied by tons of evidence in fields like endocrinology and biochemistry and so forth -- evidence that is not controversial.

So there is a huge disconnect. On the one hand, our public health experts, nutritionists, and dietitians teach us that the beer belly is a garbage bag or a piggybank -- whatever analogy you'd prefer. On the other hand, we have all this science that tells us that fat is metabolically active -- that it is essentially an endocrine organ in charge of regulating our appetite, our metabolism, and so forth.

Which of these views of fat metabolism is correct? Is our fat tissue a piggybank? Is it a complex metabolic organ? Can it be both? And once we have our answer, what might that tell us about why we get fat in the first place and how we can lose the beer belly and live a healthier life?

Two hypotheses compete to explain what drives weight gain and weight loss. The one we all know is called the Caloric Balance Hypothesis. And the one only a few know is called the Lipophilia Hypothesis.

Caloric Balance says that fat is a piggybank.

Lipophilia says that fat is metabolically active.

So what does the evidence tell us? It tells us that the latter explanation is far more robust:

1. Consider this article: "the regulation of adipose tissue distribution in humans."[1]

2. Or this one: "Adipose tissue as an endocrine organ."[2]

This paper, discusses how "adipose tissue is a complex, essential, and highly active metabolic and endocrine organ."

3. You can also read more about why and how fat tissue participates in the regulation of energy balance in Gary Taubes' book, Good Calories Bad Calories.[3]

Okay, so if fat is indeed metabolically active -- if the tissue itself can regulate appetite and metabolism -- it's a huge problem for Caloric Balance. After all, if "calories count," how exactly do they "count"? If the proposition is that we stuff excess calories into our fat tissue and that's why we get fat, what's the mechanism by which this occurs? Amazingly, we're never told. And that's because fat tissue is homeostatically regulated, much in the same way as our body temperature, blood pH, and oxygen levels are regulated. It has nothing to do with psychology. It has nothing to do with something as simple as "Calories In" and "Calories Out." It has to do with a web of interconnected and highly interdependent hormones, enzymes, genetic influences, and so forth.

References