First, know that people rate their fullness the same regardless of how many portions they ate, according to a Cornell University study. So that second heaping helping of mashed potatoes won’t help you feel any fuller than the first.
Researchers gave participants bowls of soup. Half of those bowls, however, were rigged to continuously refill.
The people with the trick bowls ate 73 percent more than those who ate from ordinary bowls—even though they rated themselves as feeling no more full. Scientists call this use of sensory cues to assess fullness “learned satiation.”
Basically, if food keeps appearing in front of you, you’ll want to keep eating.
The best approach: Out of sight, out of mind. If you’re eating at home, put a portion of food on your plate and then return the rest to the fridge right away. If you can’t see a second helping, it’s easier not to take a second helping.
Plus, you have to physically get up to go retrieve the food, giving you time to say, “Do I really need another spoonful?”