“Even as you get near the upper reaches of the normal weight range, you begin to see increases in chronic diseases,” said JoAnn Manson, chief of the Division of Preventive Medicine, Brigham and Women’s Hospital, HMS Michael and Lee Bell Professor of Women’s Health, and HSPH professor of epidemiology. “It’s a clear gradient of increase.”
Yeah, she would say that.
And then there’s Frank Hu, professor of nutrition at Harvard:
The studies that Flegal [the author of the original study finding a negative correlation between body mass index and mortality] did use included many samples of people who were chronically ill, current smokers and elderly, according to Hu. These factors are associated with weight loss and increased mortality. In other words, people are not dying because they are slim, he said. They are slim because they are dying—of cancer or old age, for example. By doing a meta-analysis of studies that did not properly control for this bias, Flegal amplified the error in the original studies.
Hu ain’t no fatty either:
This all came pretty fast. It was only last month that the much-publicized (here and here, for example) study came out, claiming a protective effect of being overweight. Post-publication peer-review is a good thing.