Quick Facts

• New research suggests 2.0-2.4 grams of protein per kilogram of body weight daily for optimal muscle growth, higher than the traditional 1.6 g/kg recommendation
• A meta-analysis of over 50 studies involving more than 5,000 participants found resistance-trained individuals benefit from higher protein intakes
• Experts recommend distributing protein at 0.4 g/kg per meal across at least four meals throughout the day

Scientists are revising protein recommendations for muscle building after analyzing data from more than 5,000 participants across 50 studies. The new guidelines suggest resistance-trained individuals need significantly more protein than previously thought.

The latest research challenges the widely-accepted 1.6 grams per kilogram of body weight recommendation established in 2018. Studies on resistance-trained lifters consistently show that consuming 2.0-2.4 g/kg of protein daily leads to greater muscle mass gains.

“A good daily target for building muscle is 2.0 g/kg of body weight, scaling higher up to 2.4 g/kg for individuals with more advanced training or greater lean body mass,” according to the research analysis.

The American College of Sports Medicine, Academy of Nutrition and Dietetics, and Dietitians of Canada currently recommend 1.2-2.0 g/kg daily for athletes. The International Society of Sports Nutrition suggests 1.4-2.0 g/kg.

Dr. Stuart Phillips from McMaster University recommends even higher intakes for athletes cutting calories while building muscle: 1.8-2.7 g/kg of body weight daily.

Protein timing also matters for muscle building. Research shows consuming 0.4 g/kg per meal across at least four meals helps reach the minimum 1.6 g/kg daily target effectively.

“Protein has become one of the single most heavily marketed products I’ve ever seen,” said Christopher Gardner, director of nutrition studies at Stanford Prevention Research Center. However, the science shows clear benefits for higher intakes in trained individuals.

The evidence supports that additional protein ingestion above 1.6 g/kg daily leads to incremental lean body mass gains in young subjects doing resistance training. Lower body muscle strength also increased marginally with higher protein intake.

Safety remains important. UCLA Health’s Yasi Ansari notes most adults need only 0.8-1.6 g/kg daily, or 10-35% of total calories. Health experts warn that excessive protein intake above 2 g/kg may increase kidney stone risk and, depending on sources, could raise heart disease and colon cancer risk from high saturated fat intake.

For resistance-trained individuals seeking muscle growth, the research provides a clear roadmap: consume 2.0-2.4 g/kg protein daily, distribute it across four meals, maintain progressive resistance training, and focus on consistency over short-term optimization.

Read more: This Is How Much Protein You Need to Build Muscle