ITHACA, N.Y.—People who eat a portion-controlled lunch consume fewer calories without going hungry and experience weight loss, according to a new study published in the journal Appetite. The findings suggest just a 250-calorie reduction at lunch will result in a 25-pound drop over the course of one year.
Researchers at Cornell University conducted a five-week eating study, where the food intake of 17 paid volunteers was measured Mondays through Fridays. For the first week, all 17 ate whatever they wanted from a buffet. For the next two weeks, half the group selected their lunch by choosing one of six commercially available portion-controlled foods, such as Chef Boyardee Pasta or Campbell's Soup at Hand, as a substitute for the buffet lunch, but they could eat as much as they wished at other meals or snacks. For the final two weeks, the other half of the volunteers chose a portion-controlled lunch.
Over the 10 days of consuming a portion-controlled lunch, the participants consumed 250 fewer calories per day than usual and lost, on average, 1.1 pounds. The researchers found that when volunteers ate a lighter lunch, they were no hungrier than usual and didn't compensate by eating more later in the day or week to make up for the fewer calories eaten.
"The results confirm that humans do not regulate energy intake with any precision," the researchers said. "Over a year, such a regimen would result in losing at least 25 pounds."
They noted making small reductions in energy intake to compensate for the increasing number of calories available in our food environment may help prevent further weight gain, and one way of doing this could be to consume portion-controlled lunches a few times a week.
The study suggests both high-protein and high-fiber meal replacements result in weight loss not by suppressing appetite, but by providing fewer calories, and because humans do not possess accurate mechanisms to compensate for the smaller intake at a previous meal, they end up taking in fewer calories.
