Your post is quite amusing. First you move your own goalpost to not just metabolism with some science backed up (I haven't clicked it, but I agree that stuff like food preference can be genetic). Then you go straight back to your own anecdotal hot air that you try and sell as evidence for the metabolism part. No you do not eat 3000+kcal on a daily base and keep a 68kg weight if you sit on your ass all day. Anyone who describes their diet as vaguely as you has no clue how much calories they eat on an average day. Period. Full stop.
http://www.nejm.org/doi/full/10.1056...99212313272701