June 5, 2007

Kolata's "Inconvenient Truth" for Dieters

New York Times science reporter Gina Kolata has hit a home run with her new book, Rethinking Thin: the New Science of Weight Loss--and the Myths and Realities of Dieting. If you've ever tried to lose 20 lbs and failed, or if you think you are doomed because you can't lose the weight your doctor tells you you have to lose, you really need to read this book.

What Kolata has done in Rethinking Thin is to summarize the findings of mainstream research into the causes and treatments for obesity. What she finds is that, as is so often the case, well-conducted research that flies in the face of what people think ought to be true gets ignored, even when it has very important messages to communicate. Even people who consider themselves scientists are unable to accept results that tell them things they don't want to hear.

Among those things--supported by solid research done by scientists at top research organizations are these:

1. Fat people who achieve normal weight have bodies that behave like those of people undergoing severe starvation which results in changes in the brain that force the body to obsess about food and do whatever it can to regain the lost weight.

2. Because of the physiological changes caused by losing a large amount of weight, a once obese person who has achieved a normal weight has developed such a hyper-efficient metabolism that they really do gain significant weight eating 1/2 the calories that an always thin person of the same weight and build eats. This has been verified in experiments where people are kept virtually imprisoned and every morsel they eat is weighed and measured, along with a dizzying list of metabolic products they give off.

3. Every large scale diet study over the past generation no matter what diet it tested found that few people are able to maintain even a 10% weight loss over a year.

4. Children adopted at birth have body compositions at adulthood that match very closely to those of their birth parents, no matter what they ate or saw modeled by the parents in their adoptive homes. This is very strong evidence that weight is determined by genetics.

5. Several massive intervention experiments with school children who were carefully educated about diet and exercise and fed "healthy "foods found that the children learned the information but it made NO difference in their weight.

and finally, and most importantly:

6. Research data with impeccable statistics shows that people who are overweight (though not obese) are less likely to die than people who are very thin or very fat.

7. Some well-respected obesity researchers believe it is possible that the fattening of our population is a byproduct of the fact that we are raising our children from pregnancy on in a far safer, better fed environment than has ever before been seen, and that this is resulting in early remodelling of the systems of the brain that control food intake in a way that promotes weight gain.

Most interestingly, the studies you are always hearing cited in the handwringing articles the media loves to feature about the "obesity epidemic," --those studies that supposedly showed higher mortality among the overweight--cherry picked their participants to get the result they were looking for. At times they screened out as many as 90% of the people in the study to find those who would support the expected results.

These studies also relied on the participants' report of their weights rather than actually weighing them despite the fact that researchers know people almost always report lower weights than they really have. The data from the large scale NHANES study that periodically samples the U.S. population, where the participants were actually weighed, and where they were drawn from society as a whole, not carefully chosen sub-groups, found that overweight correlated with better health.


It means what I've been hammering away at for years: when we talk about "Diet" for diabetes, we should NOT be talking about achieving some impossibly low weight that has eluded most of us for years despite heroic attempts to achieve it. "DIET" for people with diabetes should mean "Eating foods that don't raise our blood sugar."

If you eat in such a way as to keep your blood sugar normal, you'll have the same health as any other person of your build, which if it is overweight (rather than obese) means you may be healthier than the super-thin supermodels you've been longing to be.

That said, the one thing I wish had been mentioned in the book, which wasn't, is the possibility that the genetic changes that cause obesity may also be a result of the rising concentrations of pesticides and industrial chemicals in our water and air and all the foods we eat.

Because experiment after experiment has shown that people without certain genetic traits cannot become fat even when fed 3 times as much as they normally eat, it is probably safe to say that people who are obese DO have some genetic damage going on. The fact that good research also shows that obesity is more frequent among the poor--who live in environments more likely to be polluted, contributes to this suspicion.


Anonymous said...

Great recap. Interesting finds reported from this book.

Jenny said...

For those of you who read the Kolata book and want a more in depth look at the research she reports on, I'd recommend "FAT: Fighting the Obesity Epidemic" by Robert Pool.

It's written at a more intelligent level than the Kolota book (which is probably why few people ever read it.) But the details of this research are what make it interesting, and Pool's book is full of the details.

Anonymous said...

Sounds great! I'll add it to the reading list. Is there anything in it about epigenetics? One of the things that I have been coming across in my reading is the tendency to pass on certain health conditions (or higher risk of developing them) because of the in utero environment, which influences the organs during the fetal development.

This is a great area of interest to me because I was presumed to have had gestational diabetes, but now I think it was a mild diabetic condition that developed pre-pregnancy that they just happened to notice at that time.

Moby Dick said...

Thanks for the great synopsis. Some of those facts/results really make a lot of sense to me, as a person who has been dieting forever.