New research indicates that weight loss supplements are not really effective in helping you shed weight.
Melinda Manore, from Oregon State University, reviewing evidence surrounding hundreds of weight loss supplements, concluded that no single product results in significant weight loss and many have side-effects.
"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."
A few products, including green tea, fibre and low-fat dairy supplements, can have a modest weight loss benefit of three to four pounds, but it is important to know that most of these supplements were tested as part of a reduced calorie diet, the International Journal of Sport Nutrition and Exercise Metabolism reports.
"For most people, unless you alter your diet and get daily exercise, no supplement is going to have a big impact," said Manore, according to an Oregon statement.
Manore looked at supplements that fell into four categories: products such as chitosan that block absorption of fat or carbohydrates, stimulants such as caffeine or ephedra that increase metabolism, products such as conjugated linoleic acid that claim to change the body composition by decreasing fat, and appetite suppressants such as soluble fibres.
She found that many products had no randomized clinical trials examining their effectiveness, and most of the research studies did not include exercise. Most of the products showed less than a two-pound weight loss benefit compared to the placebo groups.
"I don't know how you eliminate exercise from the equation. The data is very strong that exercise is crucial to not only losing weight and preserving muscle mass, but keeping the weight off," said Manore, professor of nutrition and exercise sciences at Oregon.
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.
"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," Manroe added.