Keto Diet Beginner Guide: What to Eat, What to Avoid, and Common Mistakes
What Ketosis Actually Is
Ketosis is a metabolic state where the liver converts fat into ketone bodies (beta-hydroxybutyrate, acetoacetate, acetone) which become the primary fuel for the brain and muscles. It’s induced by carbohydrate restriction. Once glucose drops below a threshold, the body ramps up fat oxidation and ketone production.
What to Eat on Keto
Yes: all meats and fish, eggs, cheese, heavy cream, butter, olive oil, avocado, nuts (except cashews — high carb), seeds, low-carb vegetables (leafy greens, broccoli, cauliflower, zucchini). Limited: berries (small amounts), plain yogurt. No: bread, pasta, rice, potatoes, most fruits, legumes, sugar, processed snacks.
What Kills Ketosis
Eating more than 50g net carbs/day. Hidden carbs in: dressings, sauces, flavored yogurts, deli meats with added sugar, most condiments. Too much protein — gluconeogenesis raises blood glucose. Stress — cortisol elevates blood sugar. Alcohol — disrupts ketone metabolism.
Managing the First Week (Keto Flu)
Days 1–4: fatigue, headache, muscle cramps, brain fog (keto flu). Cause: glycogen depletion releases sodium and water; sodium loss causes potassium and magnesium to follow. Fix: sodium (broth, extra salt), potassium (avocado, leafy greens), magnesium glycinate (400 mg/day). By week 2, most symptoms resolve.
Frequently Asked Questions
Calculate your keto macros
Open Keto Macro Calculator before you start — get your carb limit, protein, and fat targets.
Open Keto Macros