Best Protein Sources for Adults Over 40

Getting enough protein after 40 is more important than at any other point in your life — and harder, because appetite often decreases while requirements go up. Here's how to hit your targets with the highest-quality sources.

Why Protein Quality Matters More After 40

After 40, your muscles experience anabolic resistance — a reduced sensitivity to the muscle-building signal of protein. Research shows older adults need more leucine per meal to get the same muscle protein synthesis response. This means quality of protein sources matters more, not just total grams. Animal proteins consistently provide higher leucine content and bioavailability than plant proteins.

Top Protein Sources Ranked

Eggs. Near-perfect amino acid profile, high leucine, highly digestible, and cheap. Three whole eggs plus two whites gives you 25g of protein. Hard to beat for breakfast.

Greek yogurt and cottage cheese. Both are high in casein protein, which digests slowly and provides sustained amino acid release — ideal before bed. Plain Greek yogurt delivers 17–20g per cup; cottage cheese gives 25g per cup.

Chicken breast. 30g of protein per 100g cooked, virtually no fat, extremely versatile. Batch cook on Sunday and you have protein for the week.

Salmon and fatty fish. High protein plus omega-3 fatty acids that reduce inflammation and support joint health. A 6oz fillet gives 34g of protein.

Lean red meat. Beef and bison provide creatine, zinc, and iron. 90% lean ground beef or sirloin 2–3 times per week is a reasonable inclusion.

Whey protein. The highest leucine content of any protein source. Best used strategically — post-workout or when food protein is inconvenient.

For Plant-Based Adults

Soy protein has a complete amino acid profile and is the best plant option. Combine incomplete proteins to cover gaps. Plan to eat around 1.1–1.2g per pound of bodyweight to compensate for lower bioavailability.