Expert Answers to Readers’ Questions
- I am overweight. What is the best way to lose weight?
- Do my genes control how much I weigh?
- Is percentage of body fat important for health?
- Can diet pills or gastric bypass surgery help me lose weight?
The optimal way to lose weight is to follow a lower calorie diet based on the Healthy Eating Pyramid food pattern and to incorporate daily physical activity into your lifestyle. It is important to make small changes in your diet and lifestyle rather than trying to go on a “crash” diet or “fad” diet claiming you can lose five pounds in one week. On average, you should aim for losing half a pound to one pound each week. In addition, it is important to pay special attention to portion sizes. Average restaurant portion sizes are typically two to three times the amount of food an average person needs in one meal. Furthermore, successful weight loss involves a permanent lifestyle change; otherwise, you will easily regain the weight that you lost. If you need additional information or would like an individual consultation, ask your primary care physician for a referral to a registered dietician.
Genes do play a role in controlling our weight, but clearly they do not explain the huge increases in overweight and obesity we have seen in the last 30 years. We gain weight when our “calories in” (the food we eat) exceeds our “calories out” (the energy we burn). Given the genetic package we are born with, we can all improve our weight by paying attention to diet and getting regular physical activity, but some people will need to work harder than others to maintain a healthy weight. In other words, if we all eat and work out the same, we will not all look the same. Only a very small percentage of people have such a strong genetic predisposition that they will be obese no matter how hard they try. Even people who are genetically predisposed to obesity can reduce their risk of chronic disease by eating a healthful diet and staying active.
Your percentage body fat is important for your health. For an average person, your body mass index (BMI) can be a good measure of body fat. However, if you are interested in the actual percentage of body fat, the gym may or may not be the best avenue, depending on the method of body fat measurement and the training of the personnel. Some methods for measuring body fat are better than others. Skin calipers typically used in a gym are usually inaccurate, since they are dependant on the skill of the person doing the analysis. Methods using bioelectrical impedance, such as a Tanita scale or a hand-held Omron body fat analyzer, are more accurate. The gold standard for body fat measurement is either underwater weighing or a full body DEXA scan, which is very expensive and usually reserved for research purposes. Also, remember that although percent body fat is important, it is only a piece of the overall health picture.
The promise of a quick fix for excess weight has always attracted Americans. Several FDA-approved diet pills are on the market (including one prescription drug that is now available over the counter, Alli), along with scads of unapproved dietary supplements. The National Institutes of Health recommends that tested and approved diet pills be used only by people with BMIs above 30, or those with BMIs above 27 and weight-related health problems. The reason? These drugs have side effects, and for people who need to lose only a few pounds the risks may outweigh the benefits. A similar situation exists for surgery to shrink or bypass the stomach. So-called bariatric surgery is a drastic step, one that has the potential for life-threatening complications. But it can yield significant weight loss and improvement in blood pressure, blood sugar, cholesterol levels, and other cardiovascular risk factors.
The National Institutes of Health recommends bariatric surgery only for people who are severely overweight, namely those with BMIs of 40 or higher (or people with BMIs of 35 or higher who have type 2 diabetes, heart disease, or other serious weight-related health problems). Although bariatric surgery seems to work wonders—look at TV weatherman Al Roker’s 100-pound weight loss following a gastric bypass operation in 2002—the pounds can begin to creep back, as Roker has found. It also requires lifelong changes in eating habits and attention to good nutrition.
The aim of the Harvard T.H. Chan of Public Health Nutrition Source is to provide timely information on diet and nutrition for clinicians, allied health professionals, and the public. The contents of this Web site are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this Web site. The information does not mention brand names, nor does it endorse any particular products.