Patients taking anti-obesity drugs lose only "modest" amounts of weight, and many stay significantly corpulent or overweight, research reveals.
Fat pills like orlistat reduced weight by less than 5kg (11 pounds) or 5% of entire organic structure weight - which guidelines state do their usage unjustified.
Experts said the Canadian work in the British Checkup Diary demoes pills are no replacement for healthy living.
Eating less and exercising more than is essential, they said.
The intent is not just to accomplish weight loss but to cut down wellness hazard factors
Dr Colin Waine, chair of the National Fleshiness Forum
Over a billion people worldwide are fleshy or obese, making the anti-obesity drug marketplace large business.
An estimated $1.2 billion was spent on anti-obesity drugs worldwide in 2005.
The up-to-the-minute work by Professor Raj Padwal and his squad at the University of Alberta proposes in many lawsuits these pills accomplish small in footing of weight loss.
They reviewed the grounds from thirty placebo-controlled trials, involving nearly 20,000 people, where grownups took one of three anti-obesity drugs - orlistat, sibutramine or rimonabant - for a twelvemonth or longer.
The National Institute for wellness and Clinical Excellence urges stopping the usage of anti-obesity drugs if 5% of entire organic structure weight is not lost after three months.
The bulk of us would be obese by 2050, predictors predict
All of the military volunteers in the trials were deemed obese, and weighed an norm of 100kg (15.7 stone).
Orlistat reduced weight by 2.9kg, sibutramine by 4.2kg and rimonabant by 4.7kg.
Patients taking the weight loss pills were significantly more than likely to accomplish 5%-10% weight loss, compared to those who took a silent person drug, however.
But is was ill-defined whether the weight loss achieved was enough to have got large wellness and endurance benefits.
Orlistat reduced the relative incidence of diabetes in one trial and all three drugs lowered patients' degrees of certain types of cholesterol.
Fleshiness is spiralling out of control and will only be reined in by public wellness political campaigns that somehow carry people to eat less and exercising more
Professor Gareth William Carlos Williams of the University of Bristol
But harmful personal effects were recorded with all three drugs and there were high drop-out rates, with 30%-40% of patients failing to finish the trials.
A separate survey in The Lancet Arch establish patients given one of these weight loss drugs, rimonabant, were at increased hazard of terrible psychiatrical events.
Dr Colin Waine, chair of the National Fleshiness Forum, said: "The first pick have to be a healthier lifestyle, but medicine usage can be justified because fleshiness is a serious medical condition.
"The intent is not just to accomplish weight loss but to cut down wellness hazard factors. All three drugs can have got good personal effects on those."
Professor Gareth Williams, professor of medical specialty at the University of Bristol, warned of the possible harm to society if anti-obesity drugs were licensed to be sold without prescription, as already haps in the US.
"Selling anti-obesity drugs over the counter will perpetuate the myth that fleshiness can be fixed simply by popping a pill and could further sabotage the attempts to advance healthy living, which is the lone long term flight from obesity.
"Globally, fleshiness is spiralling out of control and will only be reined in by public wellness political campaigns that somehow carry people to eat less and exercising more."