Keto Calculator

The ketogenic (keto) diet is a very low-carbohydrate, high-fat diet that shifts the body's primary fuel source from glucose (from carbs) to ketones (from fat). When carbohydrate intake drops below ~50g/day (usually 20–30g for strict keto), the liver converts fatty acids into ketone bodies — beta-hydroxybutyrate, acetoacetate, and acetone — which fuel the brain and body. This metabolic state is called ketosis. The diet was originally developed in the 1920s for epilepsy treatment and gained mainstream popularity for weight loss and metabolic health.

Most people need to consume fewer than 20–50g of net carbs per day to achieve and maintain ketosis. Net carbs = total carbohydrates − dietary fiber − sugar alcohols. The threshold varies by individual — some people can stay in ketosis at 50g net carbs, while others need to stay under 20g. For reliable ketosis, especially when starting out, keep net carbs under 20g/day. As you become more keto-adapted (2–4 weeks), you can test whether slightly higher carb intake (30–50g) maintains your ketosis.

Keto-friendly foods: Meats (beef, pork, lamb, chicken, turkey), fatty fish (salmon, mackerel, sardines), eggs, full-fat dairy (butter, cheese, heavy cream, Greek yogurt in small amounts), nuts and seeds (macadamia, almonds, walnuts, chia, flax), low-carb vegetables (leafy greens, broccoli, cauliflower, zucchini, asparagus, peppers), avocados, olive oil, coconut oil. Foods to avoid: bread, pasta, rice, potatoes, corn, sugar, most fruit (except berries in small amounts), legumes, and most processed foods.

Most people reach ketosis within 2–4 days of starting a strict keto diet (under 20g net carbs). The timeline depends on: your glycogen stores (exercise depletes them faster), your individual metabolism, and how strictly you restrict carbs. Signs of ketosis: decreased appetite, fruity or acetone-like breath, increased urination, temporary fatigue ('keto flu'), improved mental clarity (after the initial adaptation). You can confirm ketosis with urine strips (Ketostix), blood ketone meters (most accurate), or breath analyzers.

Keto flu refers to a cluster of symptoms that occur in the first 1–2 weeks of starting keto: fatigue, headaches, brain fog, irritability, nausea, muscle cramps, and difficulty sleeping. It's caused primarily by rapid electrolyte loss — the kidneys excrete more sodium, potassium, and magnesium when carb intake drops. To prevent or minimize keto flu: 1) Increase sodium intake (salt food generously, drink broth). 2) Supplement potassium (avocados, leafy greens). 3) Take magnesium supplement (300–400mg/day). 4) Stay well hydrated. 5) Transition gradually if needed (reduce carbs over 1–2 weeks rather than cutting abruptly).