Researchers at the University of Michigan report that not all people who are fat are at high risk for heart attacks ( Archives of Internal Medicine , August, 2008). They showed that 51 percent of overweight adults (36 million Americans) have normal blood pressure, cholesterol and blood sugar, while 25 percent of normal- weight Americans (16 million) have high levels of at least two of these tests. The media picked up this study with headlines such as "Better to Be Fat and Fit Than Skinny and Unfit" ( New York Times , August 19, 2008).
However, the entire study is flawed. The authors measured overweight, not abdominal obesity. If you just compare weight to height to define obesity, more than 50 percent of professional football players would be obese, and they are not. I am sure that the study would show the far more harmful effects if the authors had measured abdominal obesity rather than just weight. Storing fat primarily in your belly can predict premature death. It means that a person's insulin levels are very high and high insulin levels mean that your body is not responding to insulin so you are at increased risk for a heart attack, stroke, kidney damage, arteriosclerosis and all the other harmful side effects of diabetes.
Other studies do show that it is better to be fat and fit than out-of-shape at any weight. Steven N. Blair of the University of South Carolina showed that adults over 60 who had higher levels of fitness lived longer than unfit adults, independent of how fat they were ( JAMA , December 5, 2007). He showed that fat people who were able to run on a treadmill longer than unfit, fat people had better blood tests and fewer heart attacks and deaths.
How should these studies affect you? If you are overweight, you increase your risk for heart attacks, strokes, cancers and premature death. If you store large amounts of fat primarily in your belly, you are at such great risk for premature death that you should check with your doctor and probably get a thallium stress test to see if your coronary arteries are already blocked. If they are not blocked, start a supervised exercise program and diet to lose weight and become fit. If your coronary arteries are already blocked, you will need immediate counseling about future treatment.