If I had to pick one thing that moves the needle on energy, muscle, metabolism, and aging well, it's protein. Most people I see are running short and don't realize it until we add it up. Protein keeps your muscle on as you age, keeps you full so you're not grazing all day, and gives your body what it needs to repair and rebuild. It matters even more if you're working on body composition, recovering from something, or on a weight loss protocol where holding onto lean mass is the whole game. The hard part isn't knowing you need it, it's knowing what to eat. So I put together a guide. Animal, fish, plant-based for the vegetarians and vegans, and the convenience stuff for busy days, with protein amounts and quick notes on each. Grab it below, pick a few you'll actually eat, and start paying attention this week. Trivia time 🧠 Leucine is the amino acid that flips the switch on muscle growth. It's the trigger your body needs to actually build and repair muscle, and it comes mainly from animal proteins like meat, eggs, and dairy. But here's the catch: you need a certain amount of leucine at each meal to hit that switch. Miss the threshold and your body doesn't get the full signal, no matter how much total protein is on the plate. So take a guess: how much leucine do you need per meal to maximize muscle synthesis? - About 1 gram - About 2.5 grams - About 5 grams For your reference, the answer is roughly 2.5 to 3 grams of leucine per meal (the "leucine threshold"), which is about 25 to 30 grams of high-quality protein. The aging note is real and worth the follow-up: older adults develop "anabolic resistance" and need more leucine per meal to get the same muscle-building signal, which is exactly why protein targets matter more, not less, as patients age.