Battle of the bulge

People generally gauge leanness or obesity solely on the basis of weight.  It's all about stepping on the scale. 

But it's not really weight that's the enemy, it's fat!

Comparing the couch potato and the body builder...They're both overweight according to standardized weight versus height tables.  But the couch potato's excess pounds come from fat and the body builder's excess pounds come from muscle mass. 

It is the couch potato who is at risk for diabetes, HBP, and heart disease, not the "overweight" body builder (unless the body builder is using steroids, but that's a whole other story).

It is this distinction between fat gain and weight gain that makes the recent study by Bray et al (JAMA, 307: 47-55, 2012) interesting.

Dr. Bray and his colleagues set out to determine the relative effect of excess calories and protein intake on both weight gain and fat gain.

The study consisted of 25 healthy, normal weight, ages 18-35 subjects for the study.  They lived in a controlled environment at LSU for the duration of the study.  Everything they ate was carefully controlled.

They consumed a weight stabilizing diet (calories in carefully matched with calories burned) for the first 13 - 25 days. 

The next 8 weeks they were divided into 3 groups with all 3 groups consuming a diet that contained 40% excess calories and coming from fat.

The diets of the 3 groups differed with respect to protein content.  One group consumed a low protein diet (5% of calories from protein), the second group consumed a normal amount of protein (15% of calories) and the third group consumed a high protein diet (25% of calories from protein).

The results:  Fat gain was identical for all 3 groups.  All gained about 7 pounds of fat during the 8 weeks.

Weight gain was significantly different.  The low protein group gained 7 pounds, the "normal" protein group gained 13 pounds and the high protein group gained 14 pounds.

The normal and high protein group extra weight gain was from increased muscle mass. 

The normal and high protein groups metabolic rate was 227 calories per day vs. low protein of 160 calories per day.  Lean muscle mass increases our metabolism.

While this study addressed the effect of protein content on increasing muscle mass on a high calorie diet, previous studies have shown that the protein content of the diet is also important for maintaining muscle mass on low calorie, weight loss diets or normal diets in adults over the age of 50.

High protein diets (25% of calories from protein) is significantly more effective in retaining muscle mass than either normal or low protein diets. 

Got protein?

Mary Beth Potrykus
www.mamabearproductions.net