You can make a very basic lentil soup with three 32.-oz boxes of vegetable or chicken stock; 1 cup of red lentils; and chopped onion, celery stalk, and carrot. Just season it accordingly (try curry or garlic), bringit to a boil in a large soup pot, and then turn it to low heat, simmering for about an hour. (For an extra nutrient boost, toss in some spinach, kale, or Swiss chard—cut into thin strips—for the last minute or two of cooking.) You can also keep some canned lentil soup on hand for an easy lunch, says Mangieri. When shopping, however, she recommends checking the label closely—your soup should have no more than 400mg of sodium and 3g of fat (or less) per serving.