The scene could have passed for a paid advertisement: a barista at a New York City coffee bar informed a customer that the café had run out of Splenda, the sugar substitute in the bright yellow packets. To the customer, it was tantamount to betrayal. "Are you very sure?" he asked, offering to settle for Equal or Sweet'n Low. But all that was left was sugar. The man shook his head (sugar!), pushed his cup back across the counter and demanded a refund.
It's a sentiment echoed by millions of Americans who are fanatical about getting their sweets--just as long as the sweets come sugar-free. By 2004, 180 million Americans were buying sugar-free products, according to a national survey by the Calorie Control Council, up from 109 million in 1991. A 2005 report by ACNielsen found that while the low-carb craze was fading, low-sugar packaged items represented the second-fastest-growing segment (behind organics) in the good-for-you product industry.
Cutting out sugar sounds like a winning strategy for a country that's 66% overweight or obese, but are sugar substitutes in fact good for you? The scientific record is less than absolute. Past studies of saccharin and aspartame, packaged as Sweet'n Low and Equal, respectively, suggested that large doses could cause cancer in rats, although human studies have shown no such link. The Food and Drug Administration says these high-intensity sweeteners--along with sucralose (Splenda)--pose no threat to human health. Most nutrition experts are willing to go along with that--with caveats. "I suspect that if there were anything bad we would have found it by now," says Kelly Brownell, director of Yale's Rudd Center for Food Policy and Obesity. "My real concern would be with children. Heavy-duty sweeteners haven't been proved to be unsafe, but I'm not convinced that they're safe."
It's also unclear whether switching to artificial sweeteners helps you lose weight, though a glance at our collective potbelly suggests that it doesn't. Some researchers think artificial sweeteners may actually interfere with our efforts to diet. A 2004 study by psychologists at Purdue University found that when rats were fed artificially sweetened liquids for 10 days, they lost their innate ability to gauge the calorie content of foods containing real sugar.
In nature, the sweeter the food, the greater the calories. Humans have adapted over millions of years to seek out food that tastes sweet, and not just for survival. Eating sweets can reduce levels of stress hormones, calm babies and relieve pain. Some experts suspect, however, that our desire for sweet things has been reinforced--and perhaps even intensified--by our environment. Susan Schiffman, a professor of medical psychology at Duke University Medical Center, has found that African Americans and Hispanics like their food significantly sweeter than the rest of the population--a result she suspects is from campaigns that market high-sugar grape and orange sodas to predominantly ethnic populations.
Other experts speculate that the whole American diet may be calibrated to an artificially high level of sweetness, and that we may be in danger of generalizing our propensity for sweets--artificial or otherwise--to everything we eat. "Why do we have so much sugar in things like peanut butter?" Brownell asks. "Why do they put sugar in soups?"