Is Obesity more hereditary or diet and fitness?

I'm 21 years old...5'10 and 140 and eat all sorts of high calorie foods and never gain weight. I am positive that the reason I am not gaining any weight is because of my genes both my parents were skinny as can be at my age. Could the same apply for overweight people? IS it in their genes or do you feel obesity is more about diet and fitness?Is Obesity more hereditary or diet and fitness?both



for some its genetics; due to naturally having a very SLOW metabolism. they gain easily even if they just eat little..of course obviously they are still eating too much if they are like 300lbs...they just gotta work harder than the rest of us to keep the weight off



then there are people like me who have normal metabolism, meaning i can gain/lose weight easily...if i eat too much and dont exercise ill get fat, if i starve myself i get thin