The Important Role of Protein Intake in Preserving Muscle During Weight Loss

Brought to you by AbbottThe clinical benefits of achieving and maintaining a healthy weight are significant,[i] and health care professionals play a central role in supporting patients throughout this process. The aim is to find the right balance in body composition – reducing fat mass while preserving muscle mass.[ii] As the weight management landscape continues to evolve, the role of healthcare professionals is increasingly important. During weight loss and caloric restriction, the body utilizes glycogen stores as its primary energy source. As glycogen becomes depleted, metabolism shifts toward increased fat oxidation. However, gluconeogenesis from amino acids also occurs, leading to the breakdown of skeletal muscle protein. Over time, this can result in a loss of lean muscle mass.[ii]To minimize loss of lean muscle mass during rapid weight loss, patients should follow a structured approach that combines sufficient dietary protein intake and adequate exercise.[ii]The Importance of Preserving Muscle MassAs patients lose weight, not all the reduction comes from fat mass. In fact, patients on certain weight loss medications can see up to 40% of the weight loss attributable to muscle mass.[iii],[iv] Obesity Canada recommends prioritizing adequate nutritional and protein intake, and physical activity to help preserve muscle mass at the start of any weight‑management treatment, including lifestyle interventions like diet and exercise, bariatric surgery or weight loss medications.[v]Muscle mass plays an essential role in overall health. It supports mobility, metabolic function, and glucose regulation, and helps maintain strength as people age, which is important for sustaining independence.[vi]Prioritizing Protein Intake and Physical ActivityDuring periods of calorie restriction, maintaining adequate protein intake helps counteract the body’s natural tendency to break down muscle.[vii] A 2016 systematic review and meta-analysis of 20 randomized, controlled trials investigating the effects of protein intake on energy restriction-induced changes in body mass, lean mass, and fat mass in adults over 50 years demonstrated that adults consuming higher levels of dietary protein during weight loss retained more lean mass while losing more fat compared with those consuming lower-protein diets.[viii]Analyses of 203 individuals actively attempting to lose weight in a 2025 3-week ancillary study of the International Weight Control Registry demonstrated that higher daily protein consumption is associated with lower body fat percentage and higher muscle mass, particularly when combined with physical activity.[ix]“When patients lose weight, a portion of that weight can come from muscle if nutrition isn’t carefully managed,” shares Dominique R. Williams, MD, MPH, medical director and obesity specialist at Abbott. “That’s why prioritizing protein intake and adequate nutrition is so important.” Adequate protein intake is foundational for preserving muscle during caloric restriction. A 2025 joint advisory statement from expert societies including the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society suggests higher protein targets during active weight reduction of 1.2-1.5 grams of protein per kilogram of body weight per day (up from 0.8 grams).[x],[xi] Protein distribution across meals is also important, as spreading intake throughout the day can enhance muscle protein synthesis.[xii]Protein intake can be incorporated through a variety of protein rich foods such as chicken breast, cottage cheese, Greek yogurt, lentils and beans. It’s recommended to have 20-30 g of protein within each meal to help with protein intake throughout the day.[xiii] Supplements Can Be Key to Achieving Protein TargetsFor patients who are experiencing significant weight loss, including those on weight loss medications, meeting protein targets through food alone may be challenging. In these cases, for muscle maintenance, oral nutritional supplements providing at least 20 grams of protein per serving are recommended.[xiii] Abbott’s Ensure® Protein Max 30 g is an example of complete nutrition to help patients meet their protein needs, especially when their appetite is low. Available in vanilla and chocolate flavours, it provides 30 grams of complete protein along with 27 vitamins and minerals, to help patients meet their protein goals and overall nutritional intake during weight loss. As the #1 doctor recommended brand of oral nutritional supplements,[xiv] Ensure® has been supporting nutrition for over 50 years with science-based nutritional products. The Synergy Between Protein and Physical ActivityOne of the keys to preserving muscle mass and supporting overall health is staying active. Physical activity helps maintain muscle mass while losing weight, especially when it includes strength training or resistance band exercises.[xv]Nutrition alone is insufficient to fully preserve muscle mass during weight loss.[xvi] Resistance training, such as weightlifting, body-weight exercises, or resistance band workouts, stimulates muscle protein synthesis and helps maintain muscle mass even during caloric restriction.[xvii]When adequate protein intake is combined with resistance exercise, the protective effect on muscle is even greater. A randomized, controlled 10-week study of 100 adults with overweight and obesity (55-80 years) demonstrated that individuals who combine higher protein intake with strength training are more likely to preserve or increase lean mass compared with diet alone.[xvii]The Role of Healthcare ProfessionalsAs weight loss programs become increasingly common, healthcare professionals are likely to encounter a growing number of patients requiring integrated nutritional management alongside pharmacologic treatment. Routine screening for potential nutrient inadequacy, proactive counselling on protein intake, hydration, and physical activity, and early referral to a registered dietitian may all play important roles in optimizing outcomes. In this evolving landscape, nutritional oversight will be a key component of safe and effective long-term weight management.

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