According to a new study by the American Dietetic Association, the nutrition-conscious should take calorie labeling on restaurant meals and packaged foods with a grain of salt.

The Association looked at 29 popular restaurants and 10 top-selling frozen meals from the grocery store.

The average restaurant meal had 18 percent more calories than stated while the frozen meals averaged eight percent more calories than the label claimed. At restaurants, some complimentary side dishes racked up more calories than the entrees they accompanied! (A good example is the stuffing in Swiss Chalet’s Festive Special. It has more calories than the chicken and roll.)

This calorie discrepancy could have serious implications for someone who is mindful of their waistline and frequently eating out or buying TV dinners. A mere five percent increase in caloric intake can translate into a 10-pound weight gain within a single year for the unsuspecting dieter.

The U.S. Food and Drug Administration allows for a 20 percent excess in caloric content provided that the weight of the food item is 99 percent accurate.

How do you get around not knowing for sure what’s in your food? Cook for yourself. Like all good habits, it’s hard to get started but it’s really worth it once you do.