Nutrition Calculator: Food Calories & Macro Lookup

Calories in food come from three macronutrients: protein (4 cal/g), carbohydrates (4 cal/g), and fat (9 cal/g). To calculate calories: weigh or measure your food, look up the macros per serving, and multiply: (protein_g x 4) + (carbs_g x 4) + (fat_g x 9) = total calories. A food scale ($10-15) is the most accurate way to measure portions.

Foods with the highest protein-to-calorie ratio: chicken breast (53g protein per 281 cal = 5.3 cal per g protein), egg whites (11g per 51 cal = 4.6 cal/g), tuna in water (29g per 130 cal = 4.5 cal/g), shrimp (36g per 168 cal = 4.7 cal/g), and turkey breast (34g per 153 cal = 4.5 cal/g). These are the best choices when you need to maximize protein while minimizing calories.

Cooking primarily affects weight (through water loss/absorption) and slightly alters nutrient availability. Meat loses 25-30% of its weight when cooked (water evaporates, fat renders). 8 oz of raw chicken breast becomes about 6 oz cooked but has the same protein. Vegetables may lose some water-soluble vitamins but become more digestible. Always specify raw or cooked when tracking.

Nutrition values are averages based on USDA data and food labels. Natural foods (produce, meat) vary by up to 10-20% depending on variety, growing conditions, and preparation. The values in this calculator are accurate enough for practical calorie counting. FDA food labels are allowed a 20% margin of error.

Handy approximations: palm of your hand = 3-4 oz protein (20-30g protein). Fist = 1 cup of grains/starchy carbs. Cupped hand = 1/2 cup. Thumb tip = 1 tablespoon of fat. Thumb = 1 oz of cheese. These are rough estimates — a $10-15 digital food scale is the most reliable investment for accurate tracking.