Why doesn't Diet ID track calorie intake?

Good nutrition is about both what and how much we eat on a regular basis. Body weight is a foolproof, accurate indicator of energy balance (calories in vs. calories out). If we eat too much, we gain weight. If we eat less, our weight drops. But while body weight is indeed an important indicator of disease risk, it says nothing about the foods we eat. Diet ID provides unique value by not only estimating average calorie intake, but also measuring the quality of those calories.