Myth: Lots of poor people are fat… they're not suffering.

Fact: Fat has more to do with genes and past starvation than current nutrition.


Many of our stereotypes about fat people, besides being cruel, are myths. Recent medical research shows that being overweight may not be a sign of prosperity at all, but of past poverty and starvation. The body has natural defenses against starvation, and when it experiences enough of it, it slows down the body's metabolism to make less food go further. Because poor people are more likely to go through periods of starvation than rich people, they are more likely to trigger these natural defense mechanisms.


The above myth is an unusually cruel stereotype, but one that gets repeated with surprising frequency in debates on the Internet. It is an observation many people especially make about black people: "There are too many fat black people to believe they're suffering from malnutrition and poverty."

American society has a neurotic obsession about weight. It worships an ultra-thin "ideal" personified by gaunt models and waif-like celebrities. So intense is the social pressure to conform to this unnatural weight that 200,000 American women suffer anorexia nervosa each year from trying. (1)

The flip side of this neurosis is intolerance towards fat people. And when such people also claim to be poor, critics can -- and often do -- erupt in open hostility.

Like so many prejudices, this one is rooted in myth. Dr. Martin Seligman, an authority on obesity, writes: "Nineteen out of twenty studies show that obese people consume no more calories each day than non-obese people. In one remarkable experiment, a group of very obese people dieted down to only 60 percent overweight and stayed there. They needed one hundred fewer calories a day to stay at 60 percent overweight than normal people needed to stay at a normal weight." (2)

What's going on here? In 1995, Dr. Jules Hirsch of Rockefeller University published the results of a landmark study that proved that the body has a "thermostat" when it comes to maintaining its natural weight. His research team recruited 18 people who were obese and 23 who had never been overweight. They were required to live at a clinical center while their diet and activities were carefully controlled. In volunteers who gained weight, metabolism was speeded up by 10 percent to 15 percent. In those who lost weight, metabolism was 10 percent to 15 percent slower than normal. (3)

In other words, when people fall below their natural weight, their bodies slow down metabolism to try to regain it. When people gain weight, it speeds up metabolism to burn it off.

Scientists have long known there is a significant genetic component to weight. Identical twins reared apart weigh virtually the same throughout their lives. (4) Adopted children do not resemble the weights of their adoptive parents, but they do resemble the weights of their natural parents, especially the mother. (5) Interestingly, thinness seems more inheritable than obesity, which suggests that social factors may play a greater role in obesity.

But does this mean that obesity is genetic destiny? Dr. William Bennett of Cambridge Hospital says not necessarily; he suggests that the thermostat "set point" for natural weight can shift gradually over time in response to external factors. For example, eating a high-fat diet tends to raise the set point, while regular exercise tends to lower it. (6)

Dr. Seligman argues that when a person is subjected to starvation repeatedly or over long periods, the body gradually adjusts by storing more fat in preparation for the next time. This would have been a crucial survival feature in early humans, when hunting seasons could alternate between feast and famine, not only for days but even weeks or months at a time. Natural selection would have favored those who could survive periods of prolonged starvation by storing fat more efficiently.

Interestingly, Seligman points out that the body can't tell whether starvation is voluntary or involuntary. If a person goes on a diet (a euphemism for starvation), the body's ancient survival mechanisms kick in: "The body defends its weight by refusing to release fat, by lowering its metabolism, and by insistently demanding food. The harder the [dieter] tries not to eat, the more vigorous these defenses become." (7) Seligman concludes that this is why all diets -- no exceptions -- are proven long-term failures, and why the weight loss is guaranteed to return in the following year or two.

The political ramifications of these findings are obvious. Poor people are more likely to go through repeated or prolonged periods of starvation, and the fact that they are overweight does not at all mean that they are consuming more calories than other people. Look at it this way: if they were eating more food than normal, their bodies would be burning it up faster to maintain their natural weight. A 1976 study illustrates this point dramatically. The researchers paid a group of prisoners to add 25 percent to their weight by eating twice their normal amount of food. The first few pounds came easily, but, surprisingly enough, there was no further weight gain. (8)

In light of these findings, the best response to any overweight person -- rich or poor -- should be open-mindedness and acceptance.

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1. America Anorexia and Bulimia Association, Newsletter, 1985. This statistic is widely misquoted as 150,000 to 200,000 fatalities, not sufferers. But fatalities actually number a few hundred per year.

2. Martin Seligman, What You Can Change and What You Can't (New York: Fawcett Columbine, 1993), pp. 177-8.

3. "Body Plays Weighting Games: Fat or Thin, Metabolism Adjusts to a 'Set Point'", San Jose Mercury News, March 9, 1995, p. 1A.

4. Albert Stunkard et al., "The Body-Mass Index of Twins Who Have Been Reared Apart," New England Journal of Medicine 322 (1990).

5. Albert Stunkard et al., "An Adoption Study in Human Obesity," New England Journal of Medicine 314 (1986).

6. San Jose Mercury News.

7. Seligman, p. 183.

8. E. Sims, "Experimental Obesity, Diet-Induced Thermogenesis, and Their Clinical Implications," Clinics in Endocrinology and Metabolism 5 (1976), pp. 377-95.