£1-a-day diet drug promises weight loss
But doctors warn that eating healthily and exercising is the only surefire way to stay slim
Over-the-counter diet pills will go on sale in UK chemists for the first time this week amid warnings from experts that the cure for being overweight "will never be found in a wonder drug".
GlaxoSmithKline has produced one of two pills to go on sale. It claims that Alli, a half-strength version of the prescription-only Xenical - which has been granted a licence by the European commission - can cause safe weight loss of 3lb a week. The £1-a-day drug promises to cut the weight of men and women by between 5 and 10% in four months. For an 11-stone woman, this would mean shedding more than a stone - or a dress size.
Having promised to market the drug responsibly in the UK, Glaxo is emphasising it is intended to be a supplement to a healthy diet and regular exercise. It maintains, however, that taking an Alli tablet with every meal can cause 50% more weight loss than willpower alone.
The primary ingredient of Alli is orlistat, which diminishes the body's capacity to process fat by about 25%. Undigested, this fat passes through the body causing what Glaxo describes as "an urgent need to go to the bathroom". The drug can also interfere with the absorption of some vitamins.
But in an editorial in the British Medical Journal, Gareth Williams, professor of medicine at Bristol University who carried out a trial of Alli, warned: "Possibly [because of side effects] few users will even finish their first pack of Alli, let alone buy a second, and the drug may cause only a small and transient downward blip in the otherwise inexorable climb in weight.
"Selling anti-obesity drugs over the counter will perpetuate the myth that obesity can be fixed simply by popping a pill and could further undermine efforts to promote healthy living, which is the only long-term escape from obesity."
Williams warned that weight loss achieved in clinical trials was rarely replicated outside the laboratory.
"Dieters in these trials are highly motivated and under medical supervision," he said. "People tempted to try Alli might be advised that taking it without medical supervision may achieve an average daily energy deficit of only 100kcal - equivalent to leaving a few French fries on a plate, eating an apple instead of ice cream, or (depending on enthusiasm and fitness) having 10 to 20 minutes of sex."
The second diet pill going on sale this week is Appesat, which claims to achieve weight loss of just under 2lb a week. The seaweed extract, which costs £29.95 for 50 capsules, swells up and tricks the brain into thinking the stomach is full. The pills are broken down by acid in the stomach after a few hours and are flushed out of the body as waste.
Because Appesat does not enter the bloodstream, the company claims it should carry no side-effects worse than an "upset tummy".
Appesat has been approved by the Medicines and Healthcare Products Regulatory Authority, the government body that vets new treatments. But even Appesat's own consultants are cautious about the efficacy of over-the-counter weight-control drugs.
Dr Jason Halford is director of the Kissileff Laboratory for the Study of Human Ingestive Behaviour at the University of Liverpool, which receives payment from Appesat for his advice. He said: "The cure for obesity and being overweight will never be found in a pill, packet or a wonder drug." Halford, who is also deputy chair of the Association for the Study of Obesity, said: "That can only come from enormous changes to our food and physical environment, which are going to take a long time to achieve.
"Drugs don't necessarily deal with reasons why people become obese, which are largely psychological," he said, pointing to Appesat research that found more than a third of those surveyed admitted thoughts of their next meal were the only thing that got them through their day at work. A fifth said they were addicted to overeating, while 44% regularly ate even when they were not hungry.
"Drugs that increase feelings of satiety and control hunger will not help these people," he said.
According to Mintel, the market for diet plans and products is slowing. The growth rate of products with reduced fat, calories or sugar slowed dramatically last year. Sales remain in excess of £2bn.
According to the Health Survey for England, approximately two-thirds of adults are overweight or obese, as are around a third of children.
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