The 500 calorie number is a little sketchy. For it to hold true, here are some questions: 1. How accurately do we know how many calories are needed for mainten

The 500 calorie number is a little sketchy. For it to hold true, here are some questions: 1. How accurately do we know how many calories are needed for maintenance? I would imagine this is highly variable, unless there is evidence to show it is not. People's activity can be quite different day to day. Also is there evidence that metabolism occurs at a consistent rate? If all these add up to an error that is an order of magnitude less than 500, only then can we reliably use the number 500. 2. There is some new research [1] that shows that we may have to rethink the calorie-labels based on how foods are digested. For example cooked food are sometimes digested more completely than raw food, leading to a net intake of more calories. [1] http://news.sciencemag.org/evolution/2013/02/have-we-been-miscounting-calories http://news.sciencemag.org/evolution/2013/02/have-we-been-mi...