Average weight loss was between 1 kg and 2 kg across seven of the products, depending on the supplement, and was 1.2 kg in the group getting the placebo pills. No statistically significant difference in weight loss was found for any of those products when compared with the placebo.
"Most previous studies have examined only one product. This is the first to include nine supplements with different proposed mechanisms of action and we found that not a single product was any more effective than placebo pills in producing weight loss over the two months of the study, regardless of how it claims to work," Ellrott said, adding that if there is an indication for the use of weight-loss drugs, consumers should opt for regulated obesity drugs with proven effects (prescription or over-the-counter) instead.
In a second study presented at the congress, Dr. Igho Onakpoya of Peninsula Medical School at the Universities of Exeter and Plymouth, UK, conducted the first systematic review of all existing systematic reviews of clinical trials on weight loss supplements. The analysis summarizes the state of evidence from reviews of studies involving nine popular slimming supplements, including chromium picolinate, Ephedra, bitter orange, conjugated linoleic acid (CLA), calcium, guar gum, glucomannan, chitosan and green tea.
"We found no evidence that any of these food supplements studied is an adequate treatment for reducing body weight," Onakpoya said. "Annual global sales of dietary supplements are well over $13 billion. In Western Europe, sales of weight-loss products, excluding prescription medications, topped 900 million ($1.4 billion) in 2009. The weight-loss industry in North America is worth over $50 billion and Americans spend over $1.6 billion a year on weight-loss supplements. People think these supplements a
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International Association for the Study of Obesity