The genetics of weight: why so long to be accepted

Obesity management is one of those marvelous examples of research results that take eons to be incorporated in practice. Gina Kolata documents research published in the mid 80s in the NEJM that showed weight was almost certainly genetically controlled in an environment of plenty. Twenty years later, this is only beginning to be accepted.

Obesity, in an environment of plenty, cannot be controlled by available means...

Genes Take Charge, and Diets Fall by the Wayside - New York Times

... Dr. Stunkard also pointed out the implications: “Current efforts to prevent obesity are directed toward all children (and their parents) almost indiscriminately. Yet if family environment alone has no role in obesity, efforts now directed toward persons with little genetic risk of the disorder could be refocused on the smaller number who are more vulnerable. Such persons can already be identified with some assurance: 80 percent of the offspring of two obese parents become obese, as compared with no more than 14 percent of the offspring of two parents of normal weight.”

A few years later, in 1990, Dr. Stunkard published another study in The New England Journal of Medicine, using another classic method of geneticists: investigating twins...

...The identical twins had nearly identical body mass indexes, whether they had been reared apart or together. There was more variation in the body mass indexes of the fraternal twins, who, like any siblings, share some, but not all, genes.

The researchers concluded that 70 percent of the variation in peoples’ weights may be accounted for by inheritance, a figure that means that weight is more strongly inherited than nearly any other condition, including mental illness, breast cancer or heart disease...

...The findings also provided evidence for a phenomenon that scientists like Dr. Hirsch and Dr. Leibel were certain was true — each person has a comfortable weight range to which the body gravitates. The range might span 10 or 20 pounds: someone might be able to weigh 120 to 140 pounds without too much effort. Going much above or much below the natural weight range is difficult, however; the body resists by increasing or decreasing the appetite and changing the metabolism to push the weight back to the range it seeks...

...“Those who doubt the power of basic drives, however, might note that although one can hold one’s breath, this conscious act is soon overcome by the compulsion to breathe,” Dr. Friedman wrote. “The feeling of hunger is intense and, if not as potent as the drive to breathe, is probably no less powerful than the drive to drink when one is thirsty. This is the feeling the obese must resist after they have lost a significant amount of weight.”

One reason I think this took so long to be accepted is that the results are a direct attack on the concept of responsibility and free will. In the 1960s and 1970s environment was still thought to be a far more important factor in behavior than mere biology. This was the era when menopausal symptoms were imagined, by feminists, to be socially constructed. In the 1970s 1980s sociobiology emerged, to thunderous denunciation. It had to be renamed 'evolutionary biology' to survive. It wasn't until the 1990s that Americans began to accept that biology is often destiny, and our "soul" or our environment may be much less important than our genes.

We're still processing this "retreat from responsibility", it'll take decades to figure out all the implications. This long journey, I think explains why it took 20 years to recognize what now seems obvious ...

BTW, this data supports use of the ADA to prevent workplace discrimination against obesity ...