Recent Cornell studies in movie theatres, holiday receptions, and homes showed people eat an average of 28% more total calories when they eat low-fat snacks than regular ones. "Obese people can eat up to 45% more," reports lead researcher Brian Wansink (Ph.D.), in the book, Mindless Eating: Why We Eat More Than We Think.

"People dont realize that low-fat foods are not always low-calorie foods," says Wansink. Fat is often replaced with sugar. Low-fat snacks are an average of 11% lower in calories, but people wrongly believe they are around 40% lower.

In one study, two groups of people attending a holiday open-house were given identical regular chocolates that were labeled as either "Regular" or as "Low-fat." People served themselves an average of a third more of the candies, which would have translated into 28% more calories if they had actually been low-fat. A second study showed this is because "people believe they will feel less guilty eating the low-fat foods, so they tend to overindulge, says Pierre Chandon, co-author and marketing professor at INSEAD in France. Fat is often replaced with sugar.

The complete set of research studies, published in the November issue of the Journal of Marketing Research, was cited by the Economist as one of two significant noteworthy studies published that month. It is titled, "Can Low-Fat Foods Lead to Obesity""

For policy makers and companies, the message is that new "low-fat" foods are unlikely to solve the obesity solution. People are very likely to over eat a low-fat foods even if they dont like them as much as the regular versions.

For dieters, theres also clear message. As Wansink advises in the book Mindless Eating, "Stick with the regular version, but eat a little bit less. Its better for both your diet and your taste buds."