Guide

A protein shake ends a fast once it delivers calories, so most people keep it for eating windows unless their plan allows small calorie drinks.

A protein shake ends a strict fast because calories and amino acids pull you out of fasting mode, but it can still work as a first meal.

Your muscles constantly rebuild and break down, and the balance between those two processes decides whether you gain, keep, or lose lean tissue.

Carbs provide quick energy, fats help cell health, and protein builds and repairs body tissues in a balanced macro diet.

A healthy macro split gives you plenty of carbs for energy, enough protein for muscles, and the rest from fats to aid hormones and fullness.

Protein digestion turns long chains into amino acids using stomach acid, enzymes, and intestinal cells so your body can absorb and use them.

Proteins are broken down when digestive enzymes cut peptide bonds step by step, releasing single amino acids that the small intestine can absorb.

Your body burns dietary protein for fuel by stripping nitrogen and feeding carbon skeletons into glucose and ATP production when carbs run low.

Protein digestion in the stomach starts with acid and pepsin turning compact food proteins into smaller chains for later absorption.

Protein digestion in your stomach turns big protein chains into shorter pieces so later enzymes can finish the job and release amino acids.