That jumbo slice of pizza is more than one serving, but try telling that to a hungry guy. We tend to overestimate true portion sizes, especially for certain foods, a new study in the journal Appetite shows. Ice cream is by far the food causing the most havoc, with eaters reporting, on average, consuming more than two portions less than they actually did. Whole milk and hot chocolate – with a one-portion perceived difference for each – were the next biggest culprits. If you’re going on a diet, turn to salad and nuts. People who consumed these thought they had eaten more than their fair share, which also implies that these healthy foods give you the satiated feeling faster.