Persons eating fewer, regular-sized meals with higher amounts of lean protein feel fuller than individuals eating smaller, more frequent meals, according to a new study from Purdue University.

“We found that when eating high amounts of protein, men who were trying to lose weight felt fuller throughout the day. They also experienced a reduction in late-night desire to eat and had fewer thoughts of food,” says Heather J. Leidy, assistant professor of nutrition and exercise and exercise physiology at the University of Missouri, who was a postdoctoral researcher at Purdue for this study.


The research was funded by the National Pork Board and the American Egg Board, with additional support provided by the Purdue Ingestive Behavior Research Center and the National Institutes of Health’s Indiana Clinical and Translational Sciences Institute.

“Our advice for people trying to lose weight is to add a moderate amount of protein at three regular meals a day to help appetite control and the feeling of fullness,” notes Wayne W. Campbell, professor of foods and nutrition. “Egg and lean pork products are good sources for protein, and if they are incorporated at meals when people do not normally consume protein, such as breakfast and lunch, they may prove to be a nice strategy to control weight; promote satiety, which is the feeling of being full; and retain lean tissue mass, which is essential for people as they age.”

Men were studied because they tend to eat more and are less often studied than women, Leidy says. In the study, 27 obese men were divided into a high-protein group and a normal-protein group. Both groups consumed a calorie-restricted diet for 12 weeks, 750 calories less than their normal diet, and an average of about 2,400 calories per person.

The normal-protein diet included 14% of energy from protein, 60% from carbohydrate and 26% from fat, while the high-protein diet had the same amount of fat, but 25% of energy from protein and 49% from carbohydrate.

For example, the normal-protein diet at breakfast would include sausage made from vegetable proteins, while in the high-protein diet sausage would be from vegetable proteins, but the breakfast would also include an egg substitute and Canadian bacon. The high-protein diet included 25% of total protein intake from pork and 15% from egg products.

About 40% of the protein Americans consume comes from meat products such as pork, chicken, beef and fish, and another 5% comes from eggs and egg products. Beans, legumes and soy products are also high sources of protein but aren’t as commonly consumed.

“The studies have not been done to show the superiority of these proteins with comparable quantities consumed,” he says. “What our studies are showing is that by increasing protein in the diet with these food products, the benefits of higher protein intake are noticeable.”

Eating frequency was tested because the common belief is that eating more frequent, smaller meals a day can lead to weight loss.

