How Dietary Protein and Exercise Attenuate Lean Mass Losses

Losing weight can be a challenging and frustrating process, particularly when it comes to retaining lean mass. Many people find that as they lose weight, they also lose muscle mass, which can lead to a slower metabolism, reduced strength and decreased overall physical performance. Fortunately, there are two essential tools for preventing muscle loss during weight loss: dietary protein and resistance training.

Dietary Protein

Protein is a macronutrient that is essential for building and repairing muscle tissue. When we eat protein, it is broken down into amino acids, which are then used to rebuild and repair muscle fibers.

Meta-analyses suggest that people with overweight or obesity should target 1.2-1.5 grams of protein per kilogram of ideal body weight per day to optimize for fat loss. Another study published in the Journal of the International Society of Sports Nutrition found that consuming 1.6 grams of protein per kilogram of ideal body weight per day helped preserve lean mass during a 12-week weight loss program.

When it comes to protein sources, there are plenty of options to choose from. Lean meats, such as chicken and turkey, are excellent sources of protein, as are fish, eggs, and dairy products. Vegetarian sources of protein include beans, lentils, tofu, and nuts. Choosing a variety of protein sources can help ensure that you get all the essential amino acids your body needs.

Resistance Training

Resistance training (RT), also known as strength training or weight lifting, is another essential tool for retaining lean mass during weight loss. When we lift weights or perform other resistance exercises, we create small tears in our muscle fibers. Our bodies then repair these tears, making our muscles stronger and more resilient. This process is known as muscle protein synthesis (MPS).

Research has consistently shown that resistance training can help preserve lean mass during weight loss. One study published in the Journal of Applied Physiology found that resistance training was more effective than aerobic exercise for preserving lean mass during a weight loss program.

Resistance training doesn't have to be complicated or time-consuming. Bodyweight exercises, such as push-ups, squats, and lunges, can be effective for building and maintaining muscle mass. Free weights, resistance bands, and weight machines are other options to consider.

Figure 1.

Changes in body composition during RT x higher protein (PRO: 2.4 g · kg−1 · d−1) and RT x lower protein diet (CON: 1.2 g · kg−1 · d−1 ).
Summary: Figure 1 demonstrates **combining resistance training with higher protein results in statistically significant lean mass gains and fat mass losses in people with obesity.**

Putting It All Together

To retain lean mass during weight loss, it's essential to combine dietary protein and resistance training. Aim to consume 1.2-1.5 grams of protein per kilogram of ideal body weight per day, and focus on incorporating resistance exercises into your workout routine. For active individuals trying to lose weight, additional increases in dietary protein, up to 2.4 grams of protein per kilogram of ideal body weight per day, may lead to additional improvements in body composition. By doing so, you can help ensure that you lose fat while preserving your hard-earned muscle mass.

Disclaimer: This blog post is for informational purposes only and should not be considered medical advice. Please consult with a qualified healthcare professional before starting any weight management program.

*Examine.com Protein Calculator

Peer review provided by Stephanie Garcia, RD

References:

Krieger JW, Sitren HS, Daniels MJ, Langkamp-Henken B. Effects of variation in protein and carbohydrate intake on body mass and composition during energy restriction: a meta-regression 1. Am J Clin Nutr. 2006;83(2):260-274. doi:10.1093/ajcn/83.2.260
Wycherley TP, Moran LJ, Clifton PM, Noakes M, Brinkworth GD. Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2012;96(6):1281-1298. doi:10.3945/ajcn.112.044321
Kim JE, O'Connor LE, Sands LP, Slebodnik MB, Campbell WW. Effects of dietary protein intake on body composition changes after weight loss in older adults: a systematic review and meta-analysis. Nutr Rev. 2016;74(3):210-224. doi:10.1093/nutrit/nuv065
Cava E, Yeat NC, Mittendorfer B. Preserving Healthy Muscle during Weight Loss. Adv Nutr. 2017;8(3):511-519. Published 2017 May 15. doi:10.3945/an.116.014506
Layman DK, Evans E, Baum JI, Seyler J, Erickson DJ, Boileau RA. Dietary protein and exercise have additive effects on body composition during weight loss in adult women. J Nutr. 2005;135(8):1903-1910. doi:10.1093/jn/135.8.1903
Helms ER, Zinn C, Rowlands DS, Brown SR. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. Int J Sport Nutr Exerc Metab. 2014;24(2):127-138. doi:10.1123/ijsnem.2013-0054
Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011;29 Suppl 1:S29-S38. doi:10.1080/02640414.2011.619204
Weinheimer EM, Sands LP, Campbell WW. A systematic review of the separate and combined effects of energy restriction and exercise on fat-free mass in middle-aged and older adults: implications for sarcopenic obesity. Nutr Rev. 2010;68(7):375-388. doi:10.1111/j.1753-4887.2010.00298.x
Willis LH, Slentz CA, Bateman LA, et al. Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults. J Appl Physiol (1985). 2012;113(12):1831-1837. doi:10.1152/japplphysiol.01370.2011
Longland TM, Oikawa SY, Mitchell CJ, Devries MC, Phillips SM. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. Am J Clin Nutr. 2016;103(3):738-746. doi:10.3945/ajcn.115.119339