DES MOINES, Iowa (March 30, 2011) - Dieters trying to stick to their diets, may want to look no further than lean protein, according to two studies published in the prestigious journal Obesity1,2. Including protein, such as lean pork, in three daily meals could reduce late-night desires to eat, increase feelings of fullness and decrease distracting thoughts about food, according to the research.
Researchers at Purdue University conducted two studies of overweight and obese men eating either a normal protein diet (14% of total calories from protein), or a higher protein diet (25% of total calories from protein - the additional protein mostly from lean pork and eggs), with the protein equally divided between three or six meals per day. Calories and fat did not differ between the two diets.
The researchers looked at short-term and longer term effects of the two protein levels and in both studies, the higher protein diets were associated with greater feelings of fullness during weight loss, and in the longer term study, particularly decreased late-night desires to eat - key findings that could ultimately reduce calorie intake, and affect weight loss success, according to the researchers. In the latest study, 27 men followed a calorie restricted diet for 12 weeks, while the other study looked at short-term effects of protein on hunger/appetite in 13 men fed controlled meals on four separate days.
"Our research shows that eating about a quarter of one's daily calories as lean pork and other high quality proteins three times a day is a powerful dietary weapon for people seeking weight loss," said study lead Dr. Heather Leidy, currently an Assistant Professor in the Department of Nutrition and Exercise Physiology at the University of Missouri.
High Protein Diets Redefined
"It's time to redefine 'high protein' eating for weight management. It does not mean limitless amounts of meat, fish and eggs. Instead, think a quarter of the plate roughly dedicated to a lean protein, like three ounces of pork tenderloin for example. The rest of the plate can be fruits, vegetables and higher-fiber carbohydrates," continues Dr Leidy.
The additional protein in the "higher protein" diet consisted primarily of pre-portioned quantities of lean pork and eggs. At 25% of total calories, this amounts to roughly no more than 200 protein calories (or 50 grams of protein) at each of three mealtimes. Further, this "higher protein" dietary pattern falls within the "acceptable macronutrient distribution range" (AMDR), which is 10-35 percent of total calories for protein. According to the National Academy of Sciences, the AMDR is the range associated with reduced risk for chronic diseases, while providing essential nutrients like vitamins and minerals.
Adhering to a higher protein diet like those tested in these studies is easier than ever for consumers. Today's most popular cuts of pork have 16 percent less total fat and 27 percent less saturated fat than they did 20 years ago. In fact, cuts of pork that come from the loin - including chops and roasts - and 96 percent lean ground pork are the leanest cuts of pork available. Ounce-for-ounce pork tenderloin is as lean as skinless chicken breast.
The National Pork Board has responsibility for Checkoff-funded research, promotion and consumer information projects and for communicating with pork producers and the public. Through a legislative national Pork Checkoff, pork producers invest $0.40 for each $100 value of hogs sold. The Pork Checkoff funds national and state programs in advertising, consumer information, retail and foodservice marketing, export market promotion, production improvement, technology, swine health, pork safety and environmental management.
1Leidy H, Tang M, Armstrong C, Martin C, Campbell W. The effects of consuming frequent, higher protein meals on appetite and satiety during weight loss in overweight/obese men. Obesity.2011;19:818-824.
2Leidy H, Armstrong C, Tang M, Mattes R, Campbell W. The influence of higher protein intake and greater eating frequency on appetite control in overweight and obese men. Obesity. 2010;18:1725-1732.