The effectiveness of a vast majority of weight loss supplements are backed by little evidence or none at all, according to a review published June 23 in the journal Obesity.
Researchers from multiple institutions, including Dartmouth College and the Medical College of Wisconsin, looked at 315 randomized controlled trials of 14 weight-loss supplements. They evaluated the quality of evidence as well as whether the treatments worked for weight loss.
They found that the vast majority of the studies had serious problems, including a small sample size, incomplete data, selective reporting, and lack of blinding for participants.
Only six products had some moderate, reputable evidence they might work.
The other eight products evaluated were dubiously effective, backed by studies with industry funding, or both. These are the eight ineffective treatments included in the review, and what the latest evidence says about their use and safety.
Acupuncture: this form of traditional Chinese medicine uses thin needles inserted into the body to stimulate nerves and muscles. It's been used to treat everything from chronic pain to mental health For weight loss, some studies report it can improve appetite control and insulin regulation. However, the review found most of the evidence was low-quality, and showed minor if any weight changes compared to a placebo.
Calcium/Vitamin D: both essential nutrients for overall health, these popular supplements can be beneficial for some people, but no high-quality evidence shows they can help with weight loss, especially long term.
Chocolate/cocoa: It's not likely that these treats can help you lose weight, researchers found. Studies on chocolate as a supplement were funded by industry interests, or didn't disclose their funding at all. Only one study found a significant effect, and involved specific plant based nutrients called flavanols in cacao, the raw material in chocolate.
Guar gum: A thickening substance extracted from guar beans for use in food processing, advocates claim it helps people feel full while dieting by filling the gut. Studies have found that this doesn't work, however. Researchers found only one study showed short-term weight loss in combination with diet, but its author did not disclose their funding sources.
Mind-body: this category included treatments like meditation, hypnosis, and mindfulness for weight loss. Studies focused almost entirely on women, and didn't disclose funding. Only two studies were considered to have a low risk of bias, and neither reported before and after weight loss compared to a placebo.
Phaseolus: An extract of white kidney bean, this substance reportedly helps reduce the absorption of carbohydrates to help people lose weight. Only a few studies on it were found — some research reported a minor boost to weight loss in the short term, but the studies were short-term and evidence was considered low quality.
Phenylpropylamine: this is a chemical similar to amphetamine and ephedrine, both of which are linked to weight loss and suppressed appetite, but also serious side effects. It was primarily popular in the 80s and 90s, since the FDA warned against it in 2000, when it was found to increase the risk of hemorrhagic stroke.
Other potential side effects include anxiety, insomnia, high blood pressure and chest tightness.
Pyruvate: this is a chemical byproduct naturally produced in our bodies when we break down sugar for energy. Taking it as a supplement is supposed to speed your metabolism and burn fat more quickly.
Some research on this has found it may boost weight loss in combination with diet and/or exercise, but other research found no effect and a lack of quality evidence behind its claims.
