Economy-size is a diet buster.

Ever justify eating a lot by telling yourself you just loved, loved, loved the food? You’ve been caught! Seems that the more food we have in front of us, the more we eat, no matter how good (or bad) we think it tastes.   

In this study, the researchers gave about 150 movie-goers a medium or large bucket of free popcorn. Some got fresh popcorn and others got stale, 14-day-old popcorn—blech! As the moviegoers watched Stargate, they munched…and munched...and munched.

The participants with large buckets ate 45 percent more than those with small buckets. But here's the kicker: Even people with two-week-old stale popcorn—which most described as “soggy,” “terrible” and the like—ate 34 percent more of it if they were given a large bucket. Turns out that we eat more when given giant portions, even if the food tastes awful.

So think twice before that giant, “economical” tub of ice cream winds up in your Costco shopping cart.

If you catch yourself chowing down with abandon, pause to ask yourself whether you’re really hungry—and whether the food you’re shoveling in actually tastes any good. Better yet, preempt yourself: instead of ordering a large, opt for the small. If you’re in a restaurant, try splitting your entrée in half and pausing to decide whether you’re really hungry before you dive into part two. Your waistline will thank you.

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