Eating is naturally regulated by appetite. That's why appetite and satiation exist. It's difficult to be obese when you eat only unprocessed foods. If you don't believe me, try it out. You might be surprised.
Appetite and satiation are far more complex than just "eat until your full and then stop", for instance amensiac patients have been observed to eat waaay more than they should have just because they did remember eating (Rozin et al. (1998)), even they should have by all rights been physically full. There's whole layers of cognitive, emotional, and behavioral patterns with excess food consumption.
Personally, I have been able to effectively lose and keep off weight while still enjoying all manner of unnatural foods (Ice cream, McDonald's and candy, oh my).
Food choices became about avoiding "spending" my calories on "bad deals", avoiding foods which didn't promise enjoyment commensurate to their cost.