In the study, 301 college students were given either a whole, uncut bagel, or a bagel cut into quarters; both portions weighed 82 grams and provided the same amount of calories. Subjects were allowed to eat as much or as little of the bagel as they wanted; twenty minutes later, they ate as much as they wanted of a test meal.
Researchers found that subjects who received the uncut bagel consumed more calories from both the bagel and the lunch than those who received the quartered bagel. According to Devina Wadhera, lead author, “cutting up energy-dense meal foods into smaller pieces may be beneficial to dieters who wish to make their meal more satiating while also maintaining portion control.”
Other animals — rats, specifically — behave the same way. In a similar study, hungry rats were trained to associate one arm of a maze with 30 10-mg food pellets, and another with 1 300-mg pellet. When given free reign to choose which arm they ran to, the rats preferred, and ran faster towards, the arm with the 30 10-mg food pellets.
While the research is still preliminary and experts haven’t commented on the evolutionary significance of these findings, the tendency to perceive food in this way may simply be due to an optical illusion whereby the brain tricks the stomach into believing that it’s getting more food. Says Keith Ayoob, associate clinical professor of pediatrics at the Albert Einstein College of Medicine, “Sometimes being ‘full’ is a mind game. It’s not always just what’s in your stomach.” Perhaps: according to a study from Cornell University Food and Brand Lab, we perceive portions to be bigger if they’re served on smaller plates or on plates with more color contrast between plate and food. Or, the phenomenon may simply be due to the fact that eating more more pieces of smaller food slows us down, allowing a person to stop eating before he is too full.
So, besides cutting up your bagel into fourths, how can you take advantage of this research? Here are some small ways it might add up:
- Cut your fruit into slices – bananas, apples, kiwi, mango, watermelon – or, in the case of oranges and other citrus fruits, portion them before eating. Berries are already bite-sized, so there’s no need to break them down smaller.
- Make sure the food you’re cutting into small pieces is all visible: it’s just as important that you consciously see the amount of food you’re getting as it is to eat the food piece by piece. Single-serve potato chips, for instance, are already broken into bite-sized pieces, but if you can’t see your entire portion (because they’re obscured by the bag), your brain might not perceive the actual amount of food you’re eating. The pile of food you’re about to eat serves as a visual cue as to how much food you’re consuming.
- Instead of taking bites of from a chocolate bar, break off several small pieces. Most bars already come with divisions; instead of eating a row, eat each square independently.
- Instead of cutting your sandwich in half, cut it into fourths. When it’s just cut into halves, you may feel like you have to finish the second half; with quarters, you can put away the fourth quarter for later. It might seem small, but you could be shaving 200 calories off your lunch!
- At parties, steer yourself towards already pre-portioned foods, like shrimp cocktail, caprese skewers, sliders, and edamame. Stay away from casseroles and entree-sized meals, like burgers or huge pizza slices. With the smaller appetizers, you’ll also be able to sample more foods.
On another note, you may be able to use the reverse corollary — that if humans perceive full-sized foods to contain fewer calories and are less satiated with them, they will consume more of that food — to your advantage. Keep your vegetables in their full-sized form (a whole carrot vs. carrot sticks; a whole bell pepper vs. bell pepper strips) and you might end up eating more of them!