One of the first rules of dinner is that you want each meal to include a mix of the big three: carbohydrates, protein and fat. Your carbs should come from at least one fruit or vegetable, or a whole grain; your protein should be lean, and your fat should be heart-healthy, like olive oil. "Look for a colorful plate," advises Fernstrom. "Avoid a beige plate." A beige plate indicates you've got a lot of refined or processed foods, whereas "all the stuff that makes food colorful are really good nutrients," she says.