Calories in fat But aren't calories in fats thicker? It is true that fats provide a relatively large amount of calories: 9 kcal per gram. That is a lot more than proteins and carbohydrates , both of which deliver 4 kcal per gram. And it is true that you arrive at a calorie surplus. But that does not mean that you automatically arrive when you eat fats. If you keep reasonable portions, even with fats you will not suddenly get more calories than you consume. Conversely: even if you do not eat fat, you can still arrive if you eat too many carbohydrates and proteins. Fat therefore has no direct relationship with being overweight !