just science
The basic calorie in/out concept always struck me as obviously too simple.
When I found out that the way we determined how many calories was in a given food ingredient, was by actually burning it and measuring the energy output, I knew whole concept was flawed. Our bodies simply don't "burn" food like that. We don't shit ash. There can't be a simple 1:1 correlation.
shitting ash would be so much easier!
2 bags cheetos makes orange fart dust
While there is more going on than calories in/calories out, it does make for a good starting point for many people. Part of tracking that sort of diet tends to lead to recognizing that you can eat a lot more of the healthier foods within those calories then you get from highly processed foods. Also that you're not burning off that big mac with normal exercise. It takes a lot of exercise to burn 1000 calories.