Keto Calculator

What Is a Ketogenic Diet?

A ketogenic (keto) diet is a very low-carbohydrate, high-fat eating pattern that shifts your body into a metabolic state called ketosis. In ketosis, your body burns fat for fuel instead of glucose, producing molecules called ketone bodies that serve as an alternative energy source.

The standard ketogenic diet typically limits net carbs to 20–50g per day — forcing your body to deplete its glycogen stores and switch to fat as the primary fuel source. This metabolic shift usually takes 2–7 days of strict carb restriction.

• Very low carb — Typically under 20–50g net carbs per day, or about 5–10% of total calories
• High fat — 70–75% of calories from fat to provide sustained energy and satiety
• Moderate protein — 20–25% of calories from protein to maintain muscle mass

Keto Macros Explained

The standard ketogenic macro ratio is approximately 70–75% fat, 20–25% protein, and 5–10% carbohydrates. Understanding why each macro is set at these levels is key to making keto work:

• Why high fat is essential — Fat replaces carbs as your primary energy source. Without enough fat, you'll feel fatigued, hungry, and your body may break down muscle for energy. Fat also keeps you satiated between meals.
• Why protein is moderate — Protein is critical for maintaining muscle mass, but it needs to stay moderate on keto. Excess protein can theoretically be converted to glucose through gluconeogenesis — though this concern is often overstated (see below).
• Net carbs vs. total carbs — Net carbs = total carbohydrates − fiber − sugar alcohols. Fiber and most sugar alcohols don't raise blood sugar, so they don't count toward your carb limit. This is why you can eat leafy greens liberally on keto.

Keto-Friendly Foods

Building your meals around these foods makes hitting your keto macros straightforward. Focus on whole, unprocessed options whenever possible:

• Fats & Oils — Avocado, olive oil, butter, coconut oil, MCT oil, ghee, lard
• Proteins — Eggs, fatty fish (salmon, mackerel, sardines), beef, chicken thighs, pork belly, bacon
• Low-carb vegetables — Spinach, kale, broccoli, cauliflower, zucchini, asparagus, bell peppers, mushrooms
• Dairy — Cheese (cheddar, mozzarella, brie), heavy cream, full-fat Greek yogurt, sour cream
• Nuts & seeds — Macadamia nuts, pecans, walnuts, chia seeds, flax seeds, hemp hearts
• Beverages — Water, black coffee, unsweetened tea, bone broth

Foods to avoid on keto: bread, pasta, rice, potatoes, sugar, most fruits (except small portions of berries), juice, beer, candy, pastries, and high-carb sauces like ketchup and BBQ sauce.

Common Keto Mistakes

Avoiding these pitfalls will make your keto transition smoother and your results more sustainable:

• Not tracking net carbs carefully. Hidden carbs lurk in sauces, salad dressings, "sugar-free" products, and condiments. Even small amounts add up when your limit is 20g.
• Not eating enough fat. Feeling tired, hungry, and irritable on keto usually means you're not eating enough fat. Fat is your fuel — don't fear it.
• Worrying too much about protein. While extreme protein intake can theoretically impact ketosis, moderate to high protein (1.0–2.0 g/kg lean mass) is perfectly fine and important for muscle preservation.
• Ignoring electrolytes. The "keto flu" (headaches, fatigue, cramps) is usually an electrolyte deficiency. Supplement sodium (5–7g/day), potassium (3,500–4,700mg/day), and magnesium (400–500mg/day).
• Expecting instant results. Full fat adaptation takes 2–6 weeks. Your performance may dip initially as your body learns to efficiently burn fat. Be patient.
• Not drinking enough water. Ketosis is naturally diuretic — you lose more water and electrolytes through urine. Aim for at least 2.5–3.5 liters of water daily.