Vegetables are also a boon to dieters. Because they are generally low in fat and calories, you can eat a lot of them without gaining weight. If you substitute vegetables for other, higher-calorie foods in your diet, you'll slash your calorie and fat intake, making weight management easier. The fiber in vegetables also helps you manage your weight. Fiber makes you feel fuller for a longer period, helping you eat less overall and aiding with weight loss or maintenance.