Diet aids are often more successful at shedding dollars than pounds – for manufacturers as well as consumers.
The weight-management industry, worth $11-billion in retail sales according to data company Euromonitor, should by rights be a major beneficiary of the times.
Obesity rates are surging globally and cash-strapped governments (not to mention endless women's magazines) are actively promoting weight loss.
The industry is highly innovative. Currently on the market are a powder which, sprinkled on food, signals a full stomach to the brain; an oral glucose spray that curbs cravings; and, from Vietnam, a green tea and coffee concoction that blocks fat absorption and calorie intake. Or, at least, they purport to do so.
Yet for all the demand, innovation and breadth of players – from sectors as diverse as food, pharmaceuticals, broadcasting and cosmetics – weight loss has proved a fickle business for many: what is in fashion today can be usurped by tomorrow's wonder pill or celebrity diet.
Weight Watchers has nearly half a century's experience and is no stranger to fluctuating sales. "We've had ups and downs," said chief executive David Kirchhoff. "Consumers would love a silver bullet solution."
Unilever discovered as much when its purchase of SlimFast in 2000 collided with the then-popular Atkins diet. Five years after paying $2.3-billion (U.S.), the consumer goods group took a €650-million ($848.5-million) writedown of goodwill.
Even Nestlé SA, with its mostly impeccable record on growth, has stumbled in the arena of weight loss. Last year the economic downturn took its toll on Jenny Craig, the Switzerland-based food group's weight-management business.
Cash-strapped consumers often cut back on themselves first, says Dana Fiser, chief executive of Jenny Craig. "Especially moms, and moms are a big part of our programme," she added. "Because they are really making sure they take care of the family."
Like Weight Watchers, Jenny Craig combines lower-calorie food replacements with behavioural change –fitness classes and a push toward new eating habits that proponents and independent analysts say is most effective.
The strategy has the benefit of engaging consumers, says Monica Feldman, global head of consumer research at Euromonitor, making it easier to keep customers. Less interventionist companies are trying to ape the effect through mobile apps that track goals, she adds.
"There is a lot of innovation because there is a lot of money at stake," she says. "The goal of these companies is to come up with a miracle drug that will help people lose weight."
The latest, a pill called Qnexa that purports to melt 10 per cent off users' body weight, comes from Vivus Inc. and awaits approval from the U.S. Food and Drug Administration.
Ms. Feldman predicts increased regulatory burdens, given rising side effects. Alli, the fat-absorbing drug marketed by GlaxoSmithKline PLC , had digestive side effects that precluded, as magazines delicately put it, wearing white trousers. GSK had been seeking to sell Alli, but manufacturing issues have put the disposal on hold.
"The hope for Alli was huge," Ms. Feldman said. "GSK really put a lot of money behind the launch and was hoping to make a killing in profit. But it did not happen because consumers did not like the side effect."
Such risks can be far bigger. Les Funtleyder, analyst and fund manager at Miller Tabak, cites the $13-billion litigation bill following heart valve problems linked to "fen-phen" diet pills created by pharmaceutical company Wyeth.
Yet just as that has not deterred those carrying extra pounds from searching for a miracle slimming pill, manufacturers continue to pile into the market.
Merck & Co. Inc. has joined forces with Weight Watchers, while Amway Corp. has added Nutrilite diet supplements to its door-to-door cosmetics and home care offerings.
Allergan , the U.S. Botox maker that produces stomach-constricting devices that reduce hunger, expects its business to continue to expand, regardless of the number of miracle pills.
Chief executive David Pyott said he expects demand for Lap-Bands, which are surgically implanted, to remain strong for the severely obese.
Despite the increase in demand for slimming pills, analyst Mr. Funtleyder does not think that "big pharma" will make a serious push into diet pills.
"Obesity is a big problem medically and economically, but pharma is more involved in [related diseases]such as cardiology and diabetes," he said.
Yet fat is a health issue too – albeit one disadvantaged when it comes to public funding, as Weight Watchers' Mr Kirchhoff notes.
"We come up with the best ads to convince [overweight people]to come to us and treat their weight issues and pay for it themselves," he says. "And it's the only health issue I can think of that that's the way it's done."