Tony Lambert delphine1039@videotron.ca

According to the Centers for Disease Control and Prevention (CDC), Americans are eating more calories on average than they did in the 1970s. Between 1971 and 2000, the average man added 168 calories to his daily fare, while the average woman added 335 calories a day. What’s driving this trend? Experts say it’s a combination of increased availability, bigger portions, and more high-calorie foods.

Practically everywhere we go — shopping centers, sports stadiums, movie theaters — food is readily available. You can buy snacks or meals at roadside rest stops, 24-hour convenience stores, even gyms and health clubs. Americans are spending far more on foods eaten out of the home: In 1970, we spent 27% of our food budget on away-from-home food; by 2006, that percentage had risen to 46%.

In the 1950s, fast-food restaurants offered one portion size. Today, portion sizes have ballooned, a trend that has spilled over into many other foods, from cookies and popcorn to sandwiches and steaks. A typical serving of French fries from McDonald’s contains three times more calories than when the franchise began. A single "super-sized" meal may contain 1,500–2,000 calories — all the calories that most people need for an entire day. And research shows that people will often eat what’s in front of them, even if they’re already full.

If you are trying to lose weight, let your eyes do some of the work. The Ebbinghaus-Titchener size-contrast optical illusion might help you choose smaller portions that can nudge your weight in the right direction.

In the illusion, identical circles (the white ones) look larger or smaller depending on what’s around them. How can this help you eat, and be satisfied with, less food? The trick is in your kitchenware.

To test the illusion, a Cornell University marketing expert and two colleagues hosted an ice cream social for 85 nutrition experts. Some were given big bowls, others got small ones; some were given big serving spoons, others got smaller ones. Those who used smaller bowls or smaller spoons served themselves less ice cream. Here’s the neat part: Everyone thought they served themselves the same amount, about 8 ounces, and were equally satisfied with how much they ate.

The take-home message from this study is that you may be able to trick yourself into eating less by using smaller plates, bowls, or other kitchenware.

The illusion may work in the other direction, too. If your weight has been dwindling, using larger plates or bowls may help you take in a few more calories.

For more information on weight control and health, order our special health report, Weigh Less, Live Longer: Strategies for successful weight loss, available at www.health.harvard.edu/WL.