I am not a parent, but I feel this way a lot. What I would do is:
A) Eat fattier foods at meals
When I say fatty foods I mean either healthy fats like avocado, or fats in healthy foods, like whole yogurt or whole milk. This leads a double purpose as well. Not only does fat fill up a stomach very well, but it slows down the acting rate of carbs.
B) Drink plenty of water
Drinking at least 2 glasses of water at meals is very useful. It fills you up a lot, and of course, it is great for you! Tonight, I had 4 glasses of water (although my meal was a bit salty). Although some say to drink a glass of water instead of snack I would suggest to try to drink as much water at meals as possible, instead of snack time. This is because a glass of water often leaves me unsatisfied as a snack.
C) Make sure he is HUNGRY, and not just bored.
Many times, especially with kids (like me), we just want to do something that we like to get away from what we are doing, i.e. eat. Make sure that your kid is eating because he wants food, not just because he wants to do SOMETHING as opposed to nothing.
D) Have designated meal and snack times
With everything in life, it’s good to have a schedule. Whenever I come home from school at 4:30, I have a drink, and eat a small fat or protein snack. I think that if you make his body get into a rhythm of consistent meal and snack times, maybe he won’t be so hungry at other times, because his body has gotten used eating at certain times.
Now, I’m not an expert on this, but I would say that toddlers need to eat. A lot. Make sure that he isn’t eating an unusually large amount of food before you cut his diet. And, the fact is, if he ever gets very fat, then he will probably outgrow it if he eats responsibly.
Good luck!