Smell your way to losing weight
Like almost every dieter in America, Wendy Bassett has used all sorts of weight-loss products. Nothing worked, she said, until she tried Sensa: granules she scatters on almost everything she eats, and which are supposed to make dieters less hungry by enhancing the smell and taste of food.
“Every time I touch a piece of food, I pour it on,” said Ms. Bassett, 34, an accountant in Tyler, Tex. She has been using Sensa since February. So far, she said, she has lost 30 pounds.
The maker of Sensa claims that its effectiveness is largely related to smell: the heightened scent and flavor of food that has been sprinkled with Sensa stimulate the olfactory bulb – the organ that transmits smell from the nose to the brain – to signal the “satiety center” of the hypothalamus. Hormones that suppress appetite are then released.
But can the manipulation of smell really lead to weight loss? A handful of niche products would have you believe just that.
In addition to Sensa, which has been available since last summer, there is SlimScents, aromatherapy diet pens filled with fruity or minty odors; a peppermint spray called Happy Scent; and the vanilla-doused Aroma Patch, which you wear on your hand, wrist or chest.
Last month, Compellis Pharmaceuticals of Cambridge, Mass., began human trials on a nasal spray designed to do the opposite of what Sensa does: to curb the appetite by blocking rather than enhancing smell.
“Eighty percent of what you perceive as taste is actually smell,” said Christopher Adams, a molecular biologist and the company’s founder. “The hypothesis is that if we can alter your sense of smell we can make food less palatable, because the hedonic effect – that is, the pleasurable effect you get from eating chocolate – won’t be there.”
Using smell to manipulate appetite may be an appealing premise, but only a few studies have been conducted, and some experts have doubts.
“There’s been a theory around for a number of years that if you saturate your sensory system that you’ll not be as hungry,” said Dr. Richard L. Doty, the director of the Smell and Taste Center at the University of Pennsylvania Medical Center in Philadelphia. “There needs to be more research done.”
Mark I. Friedman, associate director of Monell Chemical Senses Center in Philadelphia, said that while the sight, taste or smell of food may result in the release of insulin and an increase in metabolism, “those kinds of effects are short-lived. If you constantly smelled something you would adapt to the odor, and you wouldn’t smell it anymore.”
But Sensa’s maker, Dr. Alan Hirsch, is confident that his product – which contains malodextrin, tricalcium phosphate, silica and natural and artificial flavors – works.
“A large part of the reason that you feel full is your brain interpreting that you’ve smelled it and tasted it,” said Dr. Hirsch, a neurologist, psychiatrist and the founder of the Smell and Taste Treatment and Research Foundation in Chicago.
Dr. Hirsch has conducted several studies on smell, taste and appetite. In the early 1990s, he gave 3,193 patients inhalers containing aromatic ingredients, which they inhaled whenever they were hungry. They were instructed to keep their normal diet and exercise routines, and each month for a period of six months they were given new inhalers. The participants lost an average of 5 pounds a month, he said.
Around that same time, Dr. Hirsch licensed this research to the company that created SlimScents. (Shortly thereafter, he revoked the license, because of business disagreements, he said, although the company has continued to market the product.) Later, Dr. Hirsch went a step further by focusing on both smell and taste. In 2005, he gave 1,436 patients granules called Tastant crystals. His theory was that these granules, later marketed as Sensa, would trick the brain into thinking it was full. According to the study, the average weight loss was 30.5 pounds over six months, with a 5-point drop in Body Mass Index.
Kimberly Tobman, a spokeswoman for Sensa, said that “hundreds of thousands” of customers have used it. It is available at TrySensa.com and on television shopping networks, and costs $59 for a one-month supply, $145 for three months and $235 for six months. There are also several blogs devoted to the product.
But there are detractors. As a woman named Mikaela wrote on http://www.real/ -customer-comments.com, a site devoted to weight loss, on April 3: “It didn’t make me feel full and decided against continuing it.”
But other researchers have found a link between scent and weight loss.
About a year and a half ago, Bryan Raudenbush, an associate professor of psychology at Wheeling Jesuit University in Wheeling, W. Va., asked 40 people to sniff peppermint every two hours for five days. For another five days he gave them a placebo. During the week they sniffed peppermint, they consumed 1,800 fewer calories.
LAST year, after hearing about Dr. Raudenbush’s and Dr. Hirsch’s work, Donna Schilder, a business and life coach in Long Beach, Calif., brought Peppermint Happy Scent to market. “Whenever clients feel an urge to eat something, they take it out, shake it and smell it,” said Ms. Schilder, who charges $5.50 for each jar of silicon beads, which have been dipped in scented oil. She stressed that she did not make any promises about her product.
Mark Cohen, the founder of SlimScents, an aromatherapy inhalant, guarantees that his product works; he is prepared to offer it free for six months (minus shipping and handling) or until a person loses 2.5 percent of his or her body weight.
“We’ve never found a person who used the product correctly and didn’t lose weight,” he said.
Still, Dr. Friedman and others point out the lack of research supporting the link between smell and weight loss.
“There’s no scientific evidence that smelling or tasting flavors is going to suppress your intake over a nutritionally significant interval,” he said.