If one gram of fat contains 9 calories, and there are about 454 grams in a pound, how come 1 pound of fat is commonly equated to be about 3,500 calories instead of about 4,000 calories?

Question

If one gram of fat contains 9 calories, and there are about 454 grams in a pound, how come 1 pound of fat is commonly equated to be about 3,500 calories instead of about 4,000 calories?

In: 10

Answer 1

1 pound of pure oil would be close to your approximation, but human fat tissue (the thing usually being talked about with ‘1 pound of fat’ statements) involves much more than pure oil. There’s water being held in there and any connecting tissue that keeps it in place. Plus there’s all the other things involved with metabolism that make the ‘pure’ conversion less useful; a healthy person’s weight can fluctuate by multiple pounds depending on hydration levels alone. So diets that are translating a weight goal to a diet goal, the ‘3500’ number works well enough, but nobody is measuring the exact calorie change to exact weight change with reliable results anyway.