A lot of people "don't diet" but are religious about exercise. 

They often say things like, "I eat what I want but I just always exercise a lot."  

Often times people in this situation tend to have a super intense relationship with exercise. They might like more "serious" versions of exercise like crossfit, or hot yoga or pure barre or soulcycle. The intensity of the exercise is important to this eater because the harder the workout, the more calories one burns. 

The more calories burned, the more comfortable this person feels eating what they like. 

I used to be this person.