The calories in food come from its macronutrients. Each gram of protein, carbohydrate, and fat contributes a fixed amount of energy.
Calories = (Protein × 4) + (Carbs × 4) + (Fat × 9)
Where
| Protein | grams of protein |
| Carbs | grams of carbohydrate |
| Fat | grams of fat |
Worked example
A food with 30 g protein, 40 g carbs, and 10 g fat has (30×4) + (40×4) + (10×9) = 120 + 160 + 90 = 370 calories.
Alcohol adds 7 calories per gram. Fat is the most energy-dense at 9 per gram, which is why high-fat foods are calorie-heavy for their size.
Estimate needs with the Calorie and TDEE calculator in the cooking calculators.