Rethinking Thin: The New Science of Weight Loss---and the Myths and Realities of Dieting
by Gina Kolata
Not too long ago, I thought that anyone who was overweight chose to be overweight, and that if they really wanted to be thin, they could. Many people still think this about the overweight and obese- why can’t they just eat less and exercise more? What’s keeping them from getting control of their lives? Well, according to Kolata’s book, this is a question that has been puzzling scientists for decades. And, spoiler alert, it’s rarely the obese person who is to blame for their weight.
In our thin obsessed culture, each new diet promises those struggling with their weight that they can “get back in control of their life,” and “finally have that body they always dreamed of.” The diet industry in America generates billions of dollars a year- yet more and more people are overweight. In fact, 95% of people who lose a significant amount of weight will put it back on within four years. So it seems pretty obvious that no diet, pill, or behavior modification can work. Why not?
Kolata follows many scientists, researchers and dieters to figure out why. She details dozens of experiments, and some of them were really fascinating. Over the years, many theories have been debunked thanks to various experiments, like that obesity is a psychological problem, or that overweight people have a slower metabolism than thin people. What researchers do know is that fat people have more fat cells than thin people- and when they are put on a strict diet, these fat cells shrink significantly. In 1954, a man named Jules Hirsch decided to house several obese people in a hospital at Rockefeller University and put them on a strict diet of 600 calories a day. They all lost about 100 pounds each after six months, and Hirsch assumed that when they left the hospital they would be able to keep the weight off easily. All of them regained their weight. This disproved the notion that fat people must want to be fat- because each formerly obese person was ecstatic about their new, thin selves, so what went wrong? The experiment was repeated again and again with the same results. Hirsch and his colleagues figured out that when the patients had lost all that weight, their bodies had changed so much that they clung on to every calorie that was eaten, making it harder and harder for them to stay thin- and easier for them to put the weight back on.
Before the diet began, the fat people had a normal metabolism- the number of calories burned per square meter of body surface was no different than it was for people who were thin and had never been fat. That changed substantially when they lost weight, with the formerly fat people burning as much as 24 percent fewer calories per square meter of their surface area than the calories used by those who were naturally thin….these subjects also had a psychiatric syndrome that had been termed ‘semi-starvation neurosis.’ They dreamed of food, they fantasized about food or about breaking their diet.
Physiologically, they were literally starving. Hirch concluded, “It is entirely possibly that weight reduction, instead of resulting in a normal state of obese patients, results in an abnormal state resembling that of a starved non-obese individual.” Many yo-yo dieters can relate to this phenomenon- once they lose a certain amount of weight, they plateau before starting to regain. Their body is adjusting its metabolism to start putting back on weight, and there is little any of us can do to reverse that.
Study after study by researchers all over the country just opened up more questions: if normal weight people were forced to gain weight and become obese, then would it be easier to lose? It turned out that normal weight people weren’t able to gain much weight, no matter how hard they tried. With many more calories and strict confines on physical activity, they were able to increase their weight about 20 percent, but not much more- even when some were eating 10,000 calories a day. This is because their bodies sped up their metabolisms to burn more calories. After this study, researchers figured out that almost everyone’s weight is set at a pre-determined level- think of it like a thermostat. When your weight is in the normal range, your body will either speed up or slow down your metabolism to keep it there, within about 10-15 pounds. So the next question was, when is this weight set? In adulthood, childhood, infancy or even in the womb?
Kolata’s book reads like a mystery novel: clues and setbacks abound. Doctors and researchers have been taking two steps forward and one step back for decades. Some things that have worked in rats haven’t worked in humans, or only certain humans, or only certain humans for a certain amount of time. Doctors have discovered chemicals, intervened in children’s schools and home life, and have found roadblock after roadblock.
Obese people today endure discrimination that simply isn’t acceptable in any other group. One woman said that any time she went to the doctor feeling sick he blamed it on her being fat. Even when she had a sore throat, he told her it was because she had too much fat on her neck. The stereotypes of fat people- that they are all lazy, dumb, and out of control, are very prevalent, and these people are always blamed for their weight. But a lot of times it’s out of their control. Yes- there are people who have lost a significant amount of weight and have managed to keep it off, but those people are rare, and they must dedicate themselves to a life of constant vigilance to stay that way.
Although being overweight doesn’t always mean unhealthy (that’s covered in the book, and
here), overweight people can suffer from ailments such as diabetes and knee problems, and are more likely not to get married and be paid lower wages than their normal weight colleagues.
So now researchers are trying to find a cure for obesity that somehow alters some of the most basic functions of the human body, and it is proving to be quite difficult. Kolata details all these efforts, and really will make you think twice about how we all view people who are overweight.
For further reading, check out
this amazing article by Kate Harding.