Nearly 65% of Americans are overweight or obese. The problem has become so epidemic that Congress recently funded the Centers for Disease Control and Prevention to begin state nutrition education programs, and the federal government issued its first guidelines on the identification and treatment of overweight and obesity.
While there is still some debate as to whether overweight causes Type 2 diabetes or just raises the risk of developing it, more than 90% of people with Type 2 diabetes are overweight or obese. Overweight refers to an excess of body weight compared with standards set by the National Institutes of Health and the National Heart, Lung, and Blood Institute. The excess weight may come from muscle, bone, fat, or body water. Obesity refers specifically to having an abnormally high proportion of body fat.
Weight loss is almost always recommended to overweight individuals when they are diagnosed with diabetes, because losing just 5% to 10% of one’s body weight can help insulin to work better, resulting in lower blood glucose levels. In addition, being overweight is a known risk factor for developing other health problems such as sleep apnea, cardiovascular disease, and osteoarthritis; losing weight can reduce those risks.
The formula for weight loss is simple: Energy expenditure must exceed energy intake. The calories you burn in activity and in maintaining basic bodily functions must exceed the calories you consume as food. While the formula is simple, however, putting it into practice generally requires hard work.
Given how difficult it can be to lose weight and keep it off, it’s easy to be tempted by the latest diet book or television infomercial promising fast, easy weight loss if we eat (or don’t eat) certain foods or if we use a certain product. But while some of these methods or products may bring about short-term weight loss, few work over the long term, and some are even dangerously unhealthy. Indeed, when researchers examine which methods really bring about safe, permanent weight loss, the best way to lose weight still appears to be the tried-and-true recommendation to eat less and exercise more.
Often, research into weight loss involves proposing a hypothesis and then testing it. For example, some scientists have designed pills they think will promote weight loss, then asked overweight volunteers to take them (after appropriate safety testing, of course). Others have designed diets for volunteers to follow, then observed whether the volunteers lost weight.
Recently, a group of scientists decided to approach the weight-loss puzzle from a different angle by studying the characteristics of people who had already successfully lost weight. Called the National Weight Control Registry, the study looked at the methods used by almost 800 people who had lost at least 30 pounds and had maintained that weight loss for over a year. In fact, the average person in the study lost over 60 pounds and kept off at least 30 pounds for an average of five and a half years. The study, now with over 3,000 member–participants, found that about 89% used both diet and exercise to lose and maintain their weight loss, while 10% did so through diet alone. Half of the members enrolled in commercial weight-loss programs or were under the formal guidance of a dietitian or psychologist, while the other half lost weight on their own.
Dietary regulation. The most common method participants reported using to regulate diet was to stop eating certain types of foods. The majority also had less fat in their diet than the recommended 30%. A third even got less than 20% of their calories from fat. Other relatively common dietary restrictions were limiting quantities of food and counting calories.
Exercise. Over 70% of the participants exercised enough each week to meet the American College of Sports Medicine’s (ACSM) minimum activity recommendation of burning 1,000 calories through activity per week. Over half also exceeded the ACSM’s 2000-calorie per week optimum activity level. Since studies have shown people tend to overestimate how much exercise they do, some of the impressive numbers reported may be somewhat inflated. However, increased physical activity was still a notable factor in participants’ weight loss.