Keto Diet Guide
The ketogenic diet restricts carbohydrates to under 50g/day (typically 20–30g net carbs), forcing the body into ketosis — a metabolic state where fat (as ketone bodies) replaces glucose as the primary fuel. The macronutrient split is typically 70–75% fat, 20–25% protein, and 5–10% carbohydrates.
How Ketosis Works
When glucose stores (liver glycogen, ~400–500 calories worth) are depleted through carbohydrate restriction, the liver converts fatty acids into ketone bodies (beta-hydroxybutyrate, acetoacetate, acetone). The brain, which normally runs on glucose, adapts to run on ketones within 2–4 days.
Weight Loss Evidence
Keto diets produce faster initial weight loss than low-fat diets — primarily from glycogen depletion causing water loss (3–4g water stored per gram of glycogen). Long-term (12+ months), weight loss outcomes are similar to other calorie-deficit approaches. The advantage of keto is strong hunger suppression for many people, making adherence easier.
Who It Works For (and Doesn't)
Keto shows strongest clinical benefit for type 2 diabetes and epilepsy. For epilepsy, it reduces seizures by 50%+ in about half of patients who try it. For general weight loss, it is no more effective than other approaches at equal calorie intake. People with kidney disease, gallbladder issues, or fat metabolism disorders should avoid it.