Dieters Retain More Muscle with Whey Protein & Leucine
by: Robbie Durand
The goal of any person going on a diet is to lose weight and at the same time maintain or even increase lean muscle mass. The critical components for any diet is to maintain proper protein intake, slowly reduce caloric intake, and lastly incorporate resistance exercise into your regimen. The recommended calorie-intake required to promote fat-loss while maintaining muscle mass is a 20-25% reduction in calories per day based on how your daily energy expenditure. In a review of the literature on dieting and lean muscle mass loss titled, “Changes in fat-free mass during significant weight loss: a systematic review”, the article reviews 16 medical and 17 surgical weight-loss studies. The analysis of these studies indicates that very-low-calorie diets provide rapid weight-loss, but also contribute to a substantial loss in fat-free mass (basically everything in your body that isn’t fat). Loss of muscle mass was positively correlated with increased levels of caloric restriction and exercise.
Dietary protein has long been thought to be the key to protect against dieting-induced muscle loss. In a 12-month randomized clinical trial, published in Nutrition and Metabolism, subjects went through a four-month period of weight loss followed by eight months of weight maintenance. Scientists randomly placed 130 middle-aged men and women on calorie-reduced diets that were either high-protein (30 percent of intake from protein) or low-protein (15 percent of intake from protein). The two diets were formulated to be equal in total calories, total fat, as well as fiber content. Physical activity was accounted for and found to be similar between the groups. While both groups lost weight, researchers found that more fat relative to lean body mass was lost in the high-protein group compared to the low-protein group. In the low-protein group there was about a 40 percent loss in lean tissue, while only 21 percent and 25 percent was lost in the high-protein group for men and women, respectively. This study’s results add to evidence that a diet higher in quality protein during calorie restriction helps to retain muscle mass. The protein content of a meal, especially one high in branched-chain amino acids, including leucine (found in high concentrations in whey protein), has been shown to trigger muscle synthesis and support the preservation of lean muscle mass.
In a new 2015 study published in Clinical Nutrition, researchers found that taking 2 supplements drastically enhanced lean muscle mass while on a caloric restricted diet. 60 overweight subjects, aged >55 years, participated in the study, The subjects engaged in a 13-week period of voluntary weight loss in which they ate 600 kcal less than their estimated requirement for weight maintenance (as measured by reference to their resting energy expenditure calculated with indirect calorimetry), while also engaging in a program of resistance training. The resistance training program comprised 3 sets of 20 repetitions of the following exercises: lat pull down, biceps curl, high row, shoulder press, horizontal row, chest press, triceps extension, knee extension, leg curl, and leg press. During the program, the subjects consumed a whey protein supplement containing 150kcal per serving (20g of whey protein and 3g leucine). At the end of the study, the researchers observed that the subjects lost a mean 3.1 kg of bodyweight over the 13-week period. The researchers found that 1.2g per kg of bodyweight was a cut-point predictive of greater or lesser losses in lean appendicular body mass. They noted that individuals consuming 1.2g per kg of bodyweight of protein lost much less muscle than those consuming only 1.0g per kg of bodyweight. The odds of increasing muscle mass during the weight loss period were significantly (5.2 times) higher with protein intakes >1.2g per kg of bodyweight and even higher (6.2 times) with protein intakes of >1.9g per kg of bodyweight. The researchers concluded that obese, elderly subjects can enhance the odds of increasing muscle mass while engaged in both caloric restriction and resistance training by consuming protein of >1.2g per kg of bodyweight and preferably 1.9g per kg. Be sure to incorporate a good whey based protein and some extra leucine to retain muscle mass while dieting.
Evans EM, Mojtahedi MC, Thorpe MP, Valentine RJ, Kris-Etherton PM, Layman DK. Effects of protein intake and gender on body composition changes: a randomized clinical weight loss trial. Nutr Metab (Lond) 2012;9:55. DOI:10.1186/1743-7075-9-55
Chaston TB, Dixon JB, O’Brien PE. Changes in fat-free mass during significant weight loss: a systematic review. Int J Obes (Lond). 2007 May;31(5):743-50. Epub 2006 Oct 31. Review.
Weijs PJ, Wolfe RR. Exploration of the protein requirement during weight loss in obese older adults. Clin Nutr. 2015 Mar 6.