|Review Finds No Evidence For Effective Weight Loss Supplements|
|Living - Health & Fitness|
|TS-Si News Service|
|Wednesday, 07 March 2012 03:00|
Corvallis, OR, USA. A review of the evidence around weight loss supplements has bad news for those trying to find an effective pill to lose weight and keep it off: it does not exist.
The study findings said no research evidence exists that any single product results in significant weight loss, while many have detrimental health benefits.
Melinda M. Manore of Oregon State University (OSU) reviewed the body of evidence surrounding hundreds of weight loss supplements, now a $2.4 billion industry in the United States. Her findings appear in the International Journal of Sport Nutrition and Exercise Metabolism. A few products, including green tea, fiber and low-fat dairy supplements, can have a modest weight loss benefit of 3-4 pounds (2 kilos) but, Manore says, it is important to know that most of these supplements were tested as part of a reduced calorie diet.
Melinda M. Manore, PhD, RD, CSSD, FACSM, is professor of nutrition and exercise sciences at Oregon State University (OSU).
Manore is on the Science Board for the President's Council on Fitness, Sports and Nutrition.Manore looked at supplements that fell into four categories:
Manore's research is focused on the interaction of nutrition and exercise on health and performance. Manore found that many products had no randomized clinical trials examining their effectiveness. Most of the research studies did not include exercise; moreover, most of the products showed less than a two-pound weight loss benefit compared to the placebo groups.
"What people want is to lose weight and maintain or increase lean tissue mass," Manore said. "There is no evidence that any one supplement does this. And some have side effects ranging from the unpleasant, such as bloating and gas, to very serious issues such as strokes and heart problems."
"I don't know how you eliminate exercise from the equation," Manore said. "The data is very strong that exercise is crucial to not only losing weight and preserving muscle mass, but keeping the weight off." ... "For most people, unless you alter your diet and get daily exercise, no supplement is going to have a big impact," Manore said.
As a dietician and researcher, Manore said the key to weight loss is to eat whole grains, fruits, vegetables and lean meats, reduce calorie intake of high-fat foods, and to keep moving. Depending on the individual, increasing protein may be beneficial (especially for those trying to not lose lean tissue), but the only way to lose weight is to make a lifestyle change. "Adding fiber, calcium, protein and drinking green tea can help," Manore said. "But none of these will have much effect unless you exercise and eat fruits and vegetables."
Manore's general guidelines for a healthy lifestyle include:
CitationDietary Supplements for Improving Body Composition and Reducing Body Weight: Where is the evidence? Melinda M. Manore. International Journal of Sport Nutrition and Exercise Metabolism 2012. In press.
Weight loss supplements typically fall into one of four categories depending on their hypothesized mechanism of action. These four categories are as follows: 1) products that block the absorption of fat or carbohydrate, 2) stimulants that increase thermogenesis, 3) products that change metabolism and improve body composition, and 4) products that suppress appetite or give a sense of fullness. Each category is reviewed and an overview of the current science related to their effectiveness is presented. While some weight loss supplements produce modest effects (<2kg weight loss), many have either no or few randomized clinical trials examining their effectiveness. A number of factors confound research results associated with the efficacy of weight loss supplements, such as small sample sizes, short intervention periods, little or no follow-up, and whether the supplement is given in combination with an energy restricted diet or increased exercise expenditure. There is no strong research evidence indicating that one specific supplement will produce significant weight loss (>2kg), especially long-term. Some foods or supplements, such as green tea, fiber and calcium supplements/dairy products, may complement a healthy lifestyle to produce small weight losses and/or prevent weight gain over time. Weight loss supplements containing metabolic stimulants (e.g. caffeine, ephedra, synephrine) are most likely to produce adverse side effects and should be avoided.
Keywords: stimulants, starch blockers, fat blockers, exercise, appetite suppressants.
|Last Updated on Tuesday, 06 March 2012 22:42|