I think I agree with you regarding what is best to do. & I certainly eat that way as my goal is not to lose weight.
Surely though if your body is starved of the easy-to-get energy in carbs it gets it instead from the less easy to get energy in body fat? OK you might feel sluggish etc etc but it must kinda work.??
Although as you say I usually eat the healthy things you suggest and combine it with exercise.