What should my goal BMI (body mass index) be?

Posted: May 08 in Medical Weight Loss News by Dr. Lazarus

In short, BMI was never intended to set goals for weight loss. All too often I have patients who are told they must achieve a certain BMI to qualify for a joint replacement surgery or for a preferred rate on insurance. Often they are told to lose 30, 40, or even 50% of their total body weight.

Medically, this is not an appropriate recommendation. Even with gastric bypass surgery, a 50% weight loss is highly unusual. Obesity is a chronic disease and no medical authority that I am aware of recommends achieving a certain BMI as appropriate management. Most medical benefits from obesity treatment accrue with just a 10% loss. I like to use as the definition of a successful obesity treatment program a weight loss of 10% of the total weight maintained for at least a year.

This amount of weight loss provides real and tangible medical benefits, even for the extremely obese. I had an young man last year who came in to see us at 400 pounds. He had no primary care, and at his first visit, had a blood pressure of 170/110, triglyceride count over 1000, and fasting blood sugar in the 200’s. Over 3 months, he lost 40 pounds (10%) but was later lost to follow up for nearly a year. When he next saw me, he maintained the 40 pound loss. He still weighed 360 pounds (down from the original 400), but had normal blood pressure, normal triglycerides, and normal blood sugar. Always encourage your patients that health benefits of even modest weight loss are substantial! Remember that in the diabetes prevention program a weight loss of just 7% reduced diabetes risk by two-thirds.

Many of our patients successfully lose 20-30%, and occasionally 40% of their total weight. This compares favorably with surgical approaches (average weight loss with lap band is 20%, with gastric bypass surgery 35%). However, obesity is a chronic illness and relapse is likely. Patients with obesity need long-term follow up and an active management plan to address relapse early and effectively.