University of Illinois researchers recently used "frozen entrees" to control portion size successfully in a weight-loss diet for men. The portions weren't "man"-sized; this was the same plan the dietitians used with women last year--with caloric intake adjusted upward just a tad (1,700 calories) for the male metabolism.
"We wanted to do the men's study separately because men and women do respond differently to diets, and we thought the men might have a different attitude toward the entrees," said dietitian LeaAnn Carson, who managed the study with dietitian Sandra Hannum for food science and human nutrition professor John Erdman.
But it turns out hungry men don't need outsized portions. "The men in this study didn't feel deprived, they liked the feeling of being able to cinch their belts a notch tighter, and in eight weeks they had a better idea of what a healthy portion size should be," Carson said.
In the study, soon to be published in Diabetes, Obesity and Metabolism, 60 healthy overweight men were divided into two like groups for eight weeks, both eating diets based on the USDA food-guide pyramid. The dietitians knew the exact composition of the entrees, and both diets contained the same number of calories and the same percentage of protein, fat, and carbohydrate.
The only difference was that one group used prepared frozen entrees that simply had to be popped into a microwave. The other group had to weigh, measure, and estimate serving size during food preparation.
The men who ate frozen entrees lost 16 pounds in eight weeks; the men who estimated serving size lost 12 pounds. Both groups had a significant decrease in the diastolic (or lower number) of their blood pressures, and all dieters' blood lipids profiles came down as well.
"The men who prepared their meals were given the pyramid and told what sort of servings the pyramid called for. We also told them to choose lean meats and low-fat foods. But making choices and estimating serving sizes is just harder to do, and it obviously allows more room for error," Carson said.
Both groups added certain easy-to-measure items to the diets for needed nutrients, such as an 8-ounce glass of milk, a piece of fruit, or a cup of salad, she said.
Hannum said the study is important because it shows that portion control is likely a key factor for many people who want to lose weight. "Some diets have been popular lately because they promise you can eat all you want of certain foods, and people like to hear that. This study shows how important portion control is in any weight-loss diet."
Hannum also said that more and more people are choosing not to invest large amounts of time in meal preparation, and, when people eat in restaurants regularly, they're vulnerable to weight gain from the large portions that are usually served. "People tend to consume the amount of food that's placed before them," she said.
Because packaged entrees are good-tasting and nutritionally balanced, they provide a good alternative to restaurant fast food when consumers don't have the time or the inclination to prepare a meal, she added
Four other Illinois researchers -- Ellen Evans, Lauren Petr, Chris Wharton and Linh Bui -- contributed to the study.
Masterfoods USA funded the research.