All the foods we eat contain calories—some more than others. In order to maintain a healthy weight and to have enough energy to power you through the day, you should try to take in only the amount of calories your body needs—no more, no less (I know—easier said than done!).

People today eat way more than they used to — and way more than they need to. This means that they're constantly taking in more calories than their bodies can burn. Unfortunately, lots of us don't realize that we're eating too much because we've become so used to seeing (and eating!) large portions.

Portion sizes began to increase in the 1980s and have been ballooning ever since. Take bagels, for example: 20 years ago, the average bagel had a 3-inch diameter and 140 calories. Today, bagels have a 6-inch diameter and 350 calories. One bagel that size actually contains half a person's recommended number of grain servings for an entire day!

The price of such overabundance is high. It's common knowledge that people who consistently overeat are likely to become overweight. But they also risk getting a number of medical problems, including high blood pressure, high cholesterol, type 2 diabetes, bone and joint problems, breathing and sleeping problems, and even depression. Later in life, people who overeat are at greater risk for heart disease, heart failure, and stroke.

It's easy to understand why the food industry tends to serve way more food than is necessary: Customers love to feel like they're getting the best value for their money! But the value meal is no deal when it triples our calories and sets the stage for health problems.