Here’s an article in the New England Journal of Medicine that describes the effects of weight loss on levels of various hormones that affect body weight. The authors expressed the hope that the results would shed light on why people who lose weight typically have so much trouble keeping it off.

A bit of explanation is in order here. Numerous hormones play a role in controlling appetite. Two of the best known are ghrelin and leptin. Ghrelin is a hormone produced by the stomach and pancreas that stimulates eating. Leptin is a hormone produced by the adipose tissue which inhibits eating. The more adipose tissue you have, the higher your levels of leptin will be, hence leptin acts as a brake on the production of more adipose tissue. Ghrelin is the accelerator pedal.

The authors recruited 50 overweight to obese men and women (BMI ranging from 27 to 40) for the study. Subjects were placed on an extremely low-calorie diet (500-550 calories per day) for 10 weeks. Those who lost at least ten percent of their body weight were invited to continue on an individually designed nutritional plan to maintain their weight loss for the next year. Subjects were encouraged to take at least thirty minutes of moderate exercise on most days, and all visited the clinical research unit once every two months, with dietary counseling made available by telephone between visits.

Levels of ghrelin, leptin, and several other hormones known to play a role in body weight were measured at the outset, at Week 10 (the end of the weight-loss period) and once more at Week 62 (the end of the one-year maintenance period).

Subjects lost an average of 30 pounds by the end of the weight loss period. The ones who stuck it out to the end of the study gained back an average of twelve of the thirty pounds they lost.

Levels of ghrelin (the accelerator pedal on your appetite) had risen by the end of the 10-week weight loss period, and had still not fallen back to normal by the end of the one-year maintenance period. Levels of leptin (the brake pedal on your appetite) dropped to one-third of the original level by the end of the 10 weeks and had risen back to only two-thirds by the end of Week 62. Subjects also reported greater levels of hunger, desire to eat, and preoccupation with food.

“Taken together, these findings indicate that in obese persons who have lost weight, multiple compensatory mechanisms encouraging weight gain, which persist for at least one year, must be overcome in order to maintain weight loss.”

Does that come as a surprise to anyone? Does anybody really believe that any of this research on leptins and ghrelins and what-have-you will tell us anything that is not subsumed under the commonsense observation that you become what you practice?

Apparently, some people do. The authors go on to conclude:

“[S]uccessful management of obesity will require the development of safe, effective, long-term treatments to counteract these compensatory mechanisms and reduce appetite. Given the number of alterations in appetite-regulating mechanisms that have been described so far, a combination of medications will probably be required.”

But of course. Can’t we solve all of our problems by heaving more money at the drug companies?

Then again, maybe not. Breakthroughs like the discovery of insulin for Type I Diabetes, and antibiotics for infectious diseases led to the hope that there would be a magic bullet for every disease. But these hopes have not been realized. I think it’s time to face the possibility that we have already picked all the low-lying fruit. Most of the diseases which plague modern man have complex causes. For everything we know, there are a thousand things we don’t know.

Ghrelin promotes the production of anti-inflammatory substances in the gastrointestinal tract. It activates the synthesis of nitric oxide in the lining of the blood vessels, which in turn inhibits the development of atherosclerotic plaque. It also promotes the formation of new neural connections in the brains of rats, and enhances memory and learning. What will be the effect of monkeying with people’s levels of this hormone? Maybe colitis, heart attacks, dementia?

Leptin levels that are too high trigger an inflammatory response which leads to atherosclerosis. Again, will monkeying with people’s levels of this hormone lead to more heart attacks?

By the way, these hormones are not the only ones affecting body weight. Scientists have found numerous others, including peptide YY, gastric inhibitory polypeptide, glucagon-like peptide 1, amylin, pancreatic polypeptide, cholecystokinin, and insulin. No doubt more remain to be discovered. Are people going to be taking pills to regulate levels of any or all of these, as well? What will be the cumulative effect (not to mention the cost) of all this relentless drugging? Who knows?

But I submit there is even more at stake here. Before we go any further down this road, I want people to think long and hard about the direction in which we are headed. Do we really want to try to build a society in which self-control and self-discipline are no longer necessary? What would such a society look like?

Reading contemporary discussions of these matters always makes me think of three guys standing in a hole in the ground, arguing about how to get out while ignoring the extension ladder next to them. It happens that I have a bit of experience with these matters. My joints are too far gone to do much running anymore, but last year while in Ethiopia I took up racewalking, and I continued when we arrived in Ghana. My route takes me past the University High School, and these kids are literally falling down on the ground laughing at the sight of the big hairy obruni chugging along like a steam engine. Anyway, once I got my time for three miles reliably below thirty minutes, something interesting happened. I found myself craving less food, and just that I dropped twenty pounds without trying. It was as if my body’s cells were saying, “Hey, if he’s gonna make us do this every day, we need to lighten the load.” As I said, you become what you practice.

Leptin molecule illustration via Wikimedia Commons