How genetic heritage explains obesity
Your boss blames you for something that wasn’t your fault, so you grab a chocolate bar and a bag of chips to feel better. After years of repeating this pattern — getting upset and overeating — you develop obesity, hypertension, and diabetes, which put you at risk for forming a blood clot in one of your coronary arteries.
If you do have a heart attack, some would say you brought it on yourself. But
Dr. Lee Goldman, a cardiologist and dean of the faculty of health sciences and medicine at Columbia University, would say that you’re at least in part a victim of your genes — genes which, paradoxically, once helped humans survive.
In his new book, “Too Much of a Good Thing: How Four Key Survival Traits Are Now Killing Us,” Goldman explains that our overreaction to stress, our craving for sweet, fatty, and salty foods, and even the clotting of our blood are determined by genes we acquired because they were once advantageous. Our Paleolithic ancestors needed a keen awareness of danger, an ability to pack in calories and sodium when available, and a way to avoid bleeding to death from wounds. Now, though, our genes are mismatched with our environment. Even when stress isn’t life-threatening, food isn’t scarce, and wounds aren’t frequent, our bodies behave as if they were. In a phone interview, Goldman noted that some of the most common medical conditions today — depression, anxiety, hypertension, obesity, and diabetes — are due to “formerly protective traits that may have been great when the average life expectancy was 30, but aren’t so great if we live to be 80.”
Goldman acknowledges that some people may find his perspective discouraging. “They’ll say, ‘My goodness, everything is hopeless because of our genes.’ ” But he sees his message as positive. For one thing, he said, we should stop blaming ourselves. If you have difficulty resisting foods that make you gain weight, for example, he said, “That doesn’t mean that you’re a terrible or non-virtuous person. This is the way you’ve been built.”
Goldman also believes that a clear-eyed appraisal of our genetic heritage will lead to more effective treatments. Public health measures have produced only very modest reductions in conditions such as childhood obesity and diabetes, he points out, and encouraging people to make lifestyle changes mostly hasn’t worked. Rather, he believes we should identify “genes that make us hungrier than we need to be, make us store more fat than we need, raise our cholesterol higher than we need, and make us clot more than we need” and develop therapies that either turn those genes off or blunt their effects. A new class of drugs, for example, lowers cholesterol by blocking the PCSK9 gene.
Goldman knows that some will object to his emphasis on drugs to improve human health, but he feels he’s just being realistic. “I’m not against diet and exercise and trying to do all these things as naturally as you can,” he said. “I’m just saying most of us can’t, and to pretend that we can is not in our best interests. We’re simply pretending.”