7. Cereal Sold in a Value-Size Box

The same goes for super-sized snack packages. People consume up to 22 percent more when they eat from larger packages, according to a study conducted by researchers at Cornell University's Food and Brand Lab. When people know there is more food available, they subconsciously let themselves eat more of it. The same goes for food you buy on sale: you're more likely to consume more when food costs less, according to another study. That's not to say you should spend more on food to eat less overall — it's unsustainable (and silly). If you're going to spring for a value pack of any packaged food, measure out your serving instead of eating out of the bag so you don't fall pray to your own mind's games.