Having had some recent education on the macronutrients in food, I have learned that it is important to understand where the calories in your food come from, whether from protein, carbohydrates, or fat. It look at nutrition labels completely different now.

On a nutrition label, I usually see these three macronutrients in bold, along with a few micronutrients like sodium, potassium, and cholesterol. Now I would expect that the calories from fat to total calories ratio would match the grams of fat to grams per serving ratio, but it is not so. Take this example:

US Nutrition label

72 of the 230 calories come from fat, or 31.3%. However, 8 grams of the 55 grams of the serving's mass comes from fat, or 14.5%. These are very different numbers. This is true for many other examples I could post.

Does this mean that the same mass of fat always has more calories than an equivalent mass of the other macronutrients?

1 Answer 1


You drew the right conclusion! Fat does embody more calories (about 9 kcal/g) than the same weight of carbohydrate (4 kcal/g), protein (4 kcal/g) or ethanol (7 kcal/g). These are only approximate values, though, but they have been in use since the late 19th century and the work of Wilbur Olin Atwater. For references and details see the FAO website or this article.

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