Interesting Facts I Found

I found a "program" and it was talking about how your body adjusts to your intake of calories, fats, and carbs. I thought it was interesting, but I didn't know if it was 100% true.
It stated that if you start eating less colories, your body will adjust to burn less calories, ect. Does anyone know if this is true?
The web address I found the info on is www.dietingedge.com if you want to research it.

Thank you for your help