Protein amount, quality and timing | Dr Luc van Loon

What It Covers

Professor Luc van Loon from Maastricht University discusses protein metabolism research, debunking myths about protein amount, quality, timing, and distribution. He covers muscle protein synthesis mechanisms, anabolic resistance in aging, plant versus animal proteins, and optimal intake strategies for different populations.

Key Questions Answered

• •Protein Distribution Matters More Than Previously Thought: While 100 grams of protein in one meal stimulates muscle protein synthesis for 12+ hours, even distribution across meals optimizes daily response. Most people under-consume protein at breakfast while over-consuming at dinner, missing opportunities for sustained anabolic stimulation throughout the day.
• •Anabolic Resistance Is Reversible Through Activity: Older adults show reduced muscle protein synthesis response to protein intake, but this anabolic resistance completely normalizes with regular physical activity. Even one week of leg immobilization in young people creates the same resistance pattern, proving the use-it-or-lose-it principle applies at any age.
• •Only 10% of Ingested Protein Becomes Muscle: When consuming 20 grams of protein, approximately 70% enters circulation, but only 2 grams (10%) incorporates into muscle tissue over six hours. The remaining amino acids support protein synthesis in organs like liver, gut, brain, and other tissues with turnover rates 20-fold higher than muscle.
• •Plant-Based Whole Foods Show Lower Acute Response: Whole food vegan meals produce significantly less muscle protein synthesis than omnivorous meals with equal protein and calories due to digestibility issues. However, over longer periods with protein isolates and dairy alternatives, differences disappear, suggesting processing and total intake matter more than source.
• •Elderly on Self-Selected Vegan Diets Risk Muscle Loss: When older adults (70+ years) chose their own plant-based foods without meal provision, they consumed significantly less total protein and calories, resulting in measurable muscle and strength loss. This occurs because whole plant foods have lower calorie density and higher satiety, problematic for populations with reduced appetite.