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New study with lean pork reveals protein's power to preserve lean body mass during weight loss

February 13, 2007

Reducing daily caloric intake is typically the first approach that dieters take to shed those unwanted pounds. However, a new study released today in the journal Obesity found that including protein from lean sources of pork in your diet could help you retain more lean body mass, which includes muscle, while losing weight.1

The new research, conducted by Dr. Wayne Campbell, lead researcher at Purdue University's Laboratory for Integrative Research in Nutrition, Fitness and Aging, and his colleagues evaluated the weight loss of 46 overweight or obese women who followed one of two reduced-calorie diets. One group ate a diet that included about 18 percent of their calories from protein. The other group ate a higher protein diet - about 30 percent of total calories from protein, including 6 ounces of lean pork on average per day.

"After 12 weeks, our study found that the group of women who followed a reduced-calorie eating plan while consuming a higher level of protein was more effective in maintaining lean body mass during weight loss compared to those who consumed the same amount of calories with less protein," said Dr. Wayne Campbell. In fact, the higher protein group retained nearly double the amount of lean body mass (losing just 3.3 pounds of lean mass) compared to the women on the normal protein diet (who lost 6.2 pounds of lean mass). Because muscle burns more calories, the finding is important in long-term weight control.

Lean Pork Helps Women Preserve Lean Body Mass With Weight Loss

"In addition to helping preserve lean body mass during weight loss, consuming a higher-protein diet helped retain the women's sense of satiety or fullness after meals. The women on the higher protein diet rated themselves more positively in terms of overall mood and feelings of pleasure during dieting," said Campbell, "which could help dieters stay true to their weight loss plans longer."

The researchers tracked the participants' food intake, body weight and composition, and feelings of fullness throughout the study to compare the effect of the two different diets on these outcomes.

"While previous studies have evaluated the impact higher-protein diets have on a weight-loss program, this is the first study to use pork as the only source of meat," said Ceci Snyder, MS, RD, assistant vice president of consumer marketing for the National Pork Board. "We know consumers may be surprised to learn that pork is a lean protein choice that can help you achieve your weight loss goals. In fact, there are six cuts of pork that meet the U.S. Department of Agriculture's guidelines for 'lean,' with less than 10 grams of fat, 4.5 grams of saturated fat and 95 milligrams of cholesterol per 3-ounce serving."

The study also concluded that a person's weight before dieting might play a role in the amount of lean body tissue lost on higher- versus normal-protein diets. The preservation of lean body mass was more pronounced in the pre-obese women compared with the obese women. The pre-obese group lost 2.6 pounds of lean body mass compared to 6.4 pounds of lean body mass lost by the obese women.

Choosing Lean Sources of Protein

"One of the biggest struggles I hear about with respect to dieting is the need for meal satisfaction. When individuals lack satiety or the feeling of fullness, more often then not they'll feel deprived and overeat," said Kathleen Zelman, MPH, RD. "Eating a variety of lean protein foods can help dieters stay on track."

Pork also packs a significant amount of nutrients in every lean portion. A 3-ounce serving of pork tenderloin is an "excellent" source of protein, thiamin, vitamin B6, phosphorus and niacin, and a "good" source of riboflavin, potassium and zinc, yet contributes only 6 percent of the calories in a 2,000 calorie diet.

Lean Pork Helps Women Preserve Lean Body Mass With Weight Loss

"When increasing the amount of protein you eat, it's important to make lean choices, such as pork tenderloin. According to the U.S. Department of Agriculture, pork tenderloin contains the same amount of fat and slightly less calories than the same size serving of skinless chicken breast2, often a welcomed surprise for many dieters," says Zelman.

"To find the leaner cuts of pork, I encourage my clients to look for the word 'loin' on the label, such as 'loin chop' or 'tenderloin'," added Zelman.

National Pork Board