Edward Saltzman is an internist with subspecialty training in cinical nutrition. He is the chief of the Division of Clinical Nutrition in the Department of Medicine at Tufts-New England Medical Center, where he is also the director of the Obesity Consult Center. Dr. Saltzman is a staff scientist at the Energy Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Saltzman's research has focused on how the nutrient composition of food influences how much we eat, as well as how food intake and energy expenditure change after the large weight loss observed following gastric bypass surgery.

Mike asks:
I am 5' 9" and weigh 220 lbs. According to the weight charts, I am obese. However, I run for 45 minutes a day, and consider myself somewhat healthy. I had my body fat measured and figured out that if I were to get down to a body fat percentage of 15%, I would still weigh 195, a good 30 lbs heavier than the "ideal" weight on the weight charts. Do you think the BMI is that crucial? I don't think it's fair to muscular or heavyset people. I don't think you would say Emmitt Smith is overweight, but I bet his BMI is quite high. I believe he is 5'8" and weighs 215-220.

Anyway, I am interested in what you think. To me I have a simpler way to determine whether I am at a good weight. That will be when I am able to fit in 34" pants vs the 38" ones I am currently wearing.

Saltzman's response:
BMI is a tool most useful for large populations of people, and when used in individuals it doesn't always correctly identify people who have excess body fat. There are differences in body fat for any level of BMI between different ethnic or racial groups, between men and women, and between younger and older people. While most people who have a high BMI agree that they carry excess fat, muscular persons will indeed by misclassified. Each individual can modify the BMI to accommodate his or her particular situation, as you have done.

Victor asks:
I'm a diabetic person and my diabetes mainly come from obesity and family. weight 325lb / height 5'7". What are the criteria for diabetic patients who want to do this surgery? Do you know a place in Texas that I can go and get evaluated for this surgery?

Saltzman's response:
The criteria for gastric bypass surgery in someone with a serious weight related health problem is a body mass index of 35 kg/m2 or greater. To identify appropriate local resources, your primary care physician is the best place to start. Also, the American Society for Bariatric Surgery (www.asbs.org) may be able to help you find a program near you.

Brigid asks:
Can you please comment on the less radical "lapband" surgery? Who is the best type of patient? What are the results?

Saltzman's response:
The choice between gastric bypass and Lap Band surgery is a personal one. Both can lead to substantial weight losses, but in general the gastric bypass leads to a greater loss. Since the Lap Band has only been approved for use in the US for less than three years, we can't yet tell you how Americans will do with this operation in the long-term. It is my personal opinion that patients who have a body mass index over 60 kg/m2 are most likely to reduce to a healthy weight with gastric bypass, which is based on the greater weight loss observed with the bypass. On the other hand, the Lap Band is a less extensive operation that, although not without risks, is thought to have a lower risk of surgical complications.

Melinda asks:
Have you ever heard of Overeaters Anonymous? Do you recommend that your patients go to meetings after surgery to help maintain their weight? If you don't change why you eat, then why even lose the weight? It won't stay off long term.

Saltzman's response:
Overeaters Anonymous is an organization that some people find effective for helping them eat less and better understand why they overeat. In our particular program we offer support groups for patients after surgery that are tailored to patients who have had an operation for weight loss. But it is my opinion that whether or not someone has had an operation, the best weight control will result with a strategy that helps identify the reasons for overeating and the situations in which overeating occurs. It is important to remember that "One size does not fit all", and a variety of approaches will be needed to help the increasing numbers of overweight people.

Josephine asks:
Dear Dr Saltzman, Do you find that there is any particular trend as to why some people are obese and others are not? Is there some psychological basis? Do you think that some people aren't taught to be healthy? Have there been studies conducted on different nurturing environments and how that affects whether people are obese?

Saltzman's response:
There are many theories to explain the current trends in obesity. Two things are certain: we now eat more calories than previously, and we move less. The factors involved include both those at the level of the individual and those at the level of society. Obesity is not a psychological disease, although psychological or emotional factors may promote obesity in those who are susceptible.

Some people are indeed not taught healthy eating habits, and education can help. But there are many people who know exactly what they should eat but can't manage to do it. Stress may contribute to obesity in several ways. First, some people find that eating may be an effective stress-reducer. Of course, after overeating in response to stress, some people feel even worse. Second, some scientists have proposed that stress may influence some hormones in the body (such as cortisol) that promote storage of body fat. For stress-eaters, stress reduction can help reduce overeating and help identify more healthful alternatives to overeating as a response.

To my knowledge, no studies have been conducted to determine if nurturing environments influence body weight.