After applying a number of statistical tests to the data, the researchers found that among all age groups, with few exceptions, there was no significant difference in the severity of illness between those with normal weight and overweight BMIs. There was a slight increase in the percentage of medication use among men age 40 to 70 with overweight BMIs when compared to men of normal weight.But in men and women under 40, there was no relation at all.
God it's hard to know what to think about this. Every damned thing you read in the popular press tells you being fat is bad for you, for your heart, your blood pressure, your kidneys, your arthritis, and then every once in a while there's a study like this, where there seems to be no relationship, much less a causal relationship, between being fat and being sick. And then there are all the studies saying your body knows just how fat it wants to be, and by god, it's going to be that fat, no more, no less. In ten years, there will be a pill that takes you down to fighting weight and then levels you off there. Then we'll find out if health improves just by being thinner.
And then I run across this study, which says infants with genes associated with obesity in adults gain weight faster than infants who don't. The authors suggest genes are associated with failure to thrive. Every damned thing you read says human behavior is god-awful complicated and subject to conflicting biological influences, some genetic, some not.