A medium-sized tomato (about 2.6 inches in diameter) contains approximately 22 calories
. For reference by weight, a small raw tomato (100 grams) has about 18 calories
. Calories in tomatoes come mostly from carbohydrates, with small amounts from protein and fat. For example, a 100-gram tomato has about 3.9 grams of carbs, 0.9 grams of protein, and 0.2 grams of fat
. In summary:
- Medium tomato (~123g): ~22 calories
- Small tomato (100g): ~18 calories
- Calories primarily from carbs with minimal fat and protein
