Are fat people more likely to die earlier? Two major studies have been looking into this seemingly simple question, and come out with some complicated answers.
Yes, extremely obese people are running the risk of an earlier death, but regular physical exercise seems to be a more important contributor to longevity among both the fat and the lean.
The Nurses' Health Study, one of the major research papers which looked specifically at mortality and obesity among women, discovered that coronary heart disease depended on the amount of fat around the hip and waist, rather than the overall body-mass index.
The other paper, which studied Japanese American men, found that the body-mass index was less important in assessing mortality so, again, race and sex have to be built into the picture as further complicating variables.
The second study, called the Honolulu Heart Study, also looked at the harm that can be caused by sudden weight loss and fluctuation. It concluded that these men were at no greater risk as long as they were not smokers.
The Nurses' Health Study, which involves 115,195 American women, discovered a direct correlation between a weight gain of more than 10 kg since the age of 18 and increased mortality in middle age. The lowest mortality rate among American women is found in those who are at least 15 per cent below the US average for women of similar age.
The relaxed view about weight, as published by American health groups, may be unjustified and potentially harmful, the report concludes (N Eng J Med, September 14, 1995).