An interesting study from this months Journal of the American Medical Association regarding calorie consumption and protein intake. I always instruct my clients to consume .8-1 gram of protein per pound of body weight in order to reach their goals. Most will settle around .8 but initially 1 gram or as much as 1.5 grams can be beneficial. The reason for this is the satiating effects of protein on the body, which reduces overall caloric consumption. Protein is also essential for building lean muscle and from this study it appears simply eating enough of it can save and build a portion of muscle without exercising at all!
This study was not really geared towards showing whether or not consuming protein reduced weight or increased muscle mass. The goal was to determine if protein consumption had the ability to induce weight loss even if one was over consuming calories. Unfortunately, it can not. Wishful thinking but as we all know here the answer to weight loss is a calorie reduction not the consumption of any macronutrient in varying amounts.
The study was small, incorporating only 25 people, but was in a very controlled environment. These study participants lived in a research facility for three months and for two of these months ate 1,000 calories over what they needed to maintain their body weight. One group was assigned a low-protein diet (5%), one a standard diet (15%) and another a high protein diet (25%). All of the groups gained weight, which was obvious because they were all eating additional calories.
The telling point of the study was what "type" of weight they gained. The low protein diet gained approximately 90% of their additional calories as fat but the standard and high protein diet groups stored only 50% as fat indicating that 50% of their gains came in the form of lean muscle. The low protein group lost 1.5 pounds of lean body mass, while the standard and high protein group gained 6 and 7 pounds respectively. It does not indicate the fitness level of those participating beyond "healthy" but a gain in lean muscle mass with no exercise from simply increasing protein indicates they were likely sedentary to begin with. American diets usually consist of high fat, high carb, low protein meals, which packs on the fat. Is it now safe to assume that by simply switching to a high protein diet we can gain back some of or lost lean muscle even without exercise? It flys in the face of logic and other studies to presume so but this study indicates it is possible. Muscles need protein and the RDA appears inadequate to provide the amount required to maintain muscle.
This isn't really an exercise study, all the participants were actually discouraged from exercising and therefore were expected to put on pounds. The study indicates eating a high protein diet while sedentary preserves lean muscle mass and that is a big deal. Even if you don't work out, protein is essential and can save your muscles from wasting. Lean muscle mass is a huge factor in healthy aging, therefore keeping as much of it as possible is necssary for a long and healthy life. We already know resistance training will increase lean muscle but now this study indicates simply eating more protein can prevent muscle waste associated with aging.
The take away here is slight increases in protein will increase lean muscle and reduce fat storage even without exercise. Most individuals assume they know the amount of calories they need to eat but tend to overestimate. Most people who don't exercise eat poorly simply because they feel if they aren't working out they are already unhealth so what is the point of eating right? If these participants were to have consumed a relatively high protein diet without the added calories from fat and carbs it is likely lean muscle mass would have increased the same without the additional fat. Throw in some resistance training and you are well on your way to a lean body.