Originally Posted by Pendergast

I posted 3 links earlier in the thread to studies that showed calculated calorie counts aren't the whole story when it comes to useable calories for food. Here's one of them(a 32% discrepancy between calculated calories and useable calories for almonds): Discrepancy between the Atwater factor predicted and empirically measured energy values of almonds in human diets

Nuts seem to be the most affected by the inadequacy of calculated calories to capture the real digestive calorie content of foods, but I would not be surprised if it's significant enough with other foods to make a difference for people who are pure calorie counter dieters.

Even the form of a food can affect available calories. Whole peanuts provide fewer available calories than peanuts that have been turned into peanut butter.