Do the math

• Pay attention to serving sizes. The serving sizes listed on food labels may be different from the serving sizes in your meal plan. If you eat twice the serving size listed on the label, you also double the calories, fat, carbohydrates, protein, sodium and other ingredients.

• Consider your daily calorie goals. The same goes for the Daily Value listed on food labels. This percentage, which is based on a 2,000-calorie-a-day diet, helps you gauge how much of a specific nutrient one serving of food contains, compared with recommendations for the whole day. A low amount is 5% or less; 20% or more is high. Look for foods with fats, cholesterol and sodium on the low end of the Daily Value; keep fiber, vitamins and minerals on the high end.

  If your doctor or registered dietitian recommends more or less than 2,000 calories a day, you may need to adjust the percentage accordingly — or simply use the percentage as a general frame of reference.