How are fat procentages calculated?

[AL_DA_GREAT]

If a food has 2 grams of fat, 2 grams of protein and 6 grams of carbs is the fat content:

2/10 = 20% fat

18 calories from fat/ 50 cals in total = 36% fat

[SMK41]

You have to calculate the calories from the grams. Not all macros have the same cal/gram ratio.

Fat: 1 gram = 9 calories
Protein: 1 gram = 4 calories
Carbohydrates: 1 gram = 4 calories
Alcohol: 1 gram = 7 calories


So in your example it's:

Fat Calories = 2g x 9 cal/g = 18 cal
Protein Calories = 2g x 4 cal/g = 8 cal
Carb Calories = 6g x 4 cal/g = 24 cal
Total calories = 18 cal + 8 cal + 24 cal = 50 cal
% Fat = 18 cal / 50 cal = 36%