Calories in vs. Calories out.
You could eat 1500 calories a day of McDonalds, or eat 1500 calories of a block of lard for all it matters (not that there is a lot of difference with the two), and still lose weight. If you exceed your energy, you will lose weight.
There are a few questions to ask this woman though:
1. Do you wake up every morning feeling like? I can bet they do
2. How many of those lbs burnt was fat? I would say not much
