Here's a weighty fact: Adults gain, on average, one and a half to two pounds a year.

James O. Hill, Ph.D., co-founder of the National Weight Loss Registry in Denver, suggests a prevention plan that's surprisingly manageable: Just eat 100 fewer calories a day (see our tips, below). Add exercise and you'll avoid piling on the pounds.

• Dunk chips in salsa, but pass on the cheese dip or guacamole

• Eat only half the bagel or switch to kiddie-size "minis"

• Eat the filling from a piece of pie and leave the crust

• Eat only the muffin top

• Use one capful of salad dressing rather than pouring it on, unmeasured

• Give four Hershey's Kisses you were going to eat to your hubby

• Choose a 12-ounce can of soda instead of a 20-ounce bottle

• Leave 10 French fries on your plate (from a small serving of thin-style fries, like McDonalds)

• Remove four pieces of pepperoni from your slice of pizza

• Ditch the top piece of bread from your sandwich