The Sprinkle Diet: Men vs. Women
At the end of the six months, the flavorings group lost an average of 15% of their initial body weight.
Of those in the flavorings group, "men lost it more quickly and women initially lost it slower," he says. "Postmenopausal women tended to lose as the men did."
''The more they liked the taste [of the seasoning or sweetener selected] the more they used it and the more weight they lost," Hirsch says.
"We don't know what happens beyond the six months," he says. "Some [participants] have used them for over a year and sustain or continue their weight loss, but that is anecdotal."
Also unknown, he says, is if the flavorings will work as well in those who are overweight but not obese.
While those in the study lost an average of nearly 15% of their body weight, the loss might be less in those who have less to lose, he says.
The sprinkle diet may not work for those who have lost their sense of smell, he says.
The Sprinkle Diet: Enjoying Food
Those in the study who used the flavorings may simply have enjoyed their food more, says Connie Diekman, RD, director of university nutrition for Washington University in St. Louis, who reviewed the study for WebMD.
"We typically have said that enjoyment is a key component to know when to stop eating," says Diekman, former president of the American Dietetic Association. The flavoring may simply have made the foods more enjoyable. "When you eat foods that trigger those senses [taste and smell] the brain begins to think in terms of 'I'm good,' 'I'm happy,' 'Stop eating.'"
"The magic may not be in the flavorings but in the enjoyment of the food," she says.
However, she cautions, there is another camp of weight loss research that has found the more diversity of food and flavor available, the more people tend to eat. So having many flavors available may prove tempting.
Hirsch says he has launched a line of calorie-free flavorings based on his study results. Already on the market are calorie-free sweeteners and low or no-calories spices.
Or, he says, you can focus on increasing the sensory characteristics of food -- smell and taste -- by simple measures yourself, such as sniffing your food before you eat it.