Plant foods contain thousands of natural chemicals, these are called "Phytonutrients". Hundreds of different phytonutrients exist in fruits and vegetables that protect the body from disease. No single fruit or vegetable can provide every beneficial chemical, so eating a variety of colorful foods is key. Well-known phytonutrients include carotenoids (which make carrots orange), flavonoids (which make grapes reddish), and anthocyanins (which make blueberries blue). In addition to pigments, phytonutrients impart flavors and aromas. Allyl sulfides, a group of flavonoids, are found in garlic, onion, and shallots. Phytonutrients are usually most beneficial when consumed in raw foods.
One of the vital roles phytonutrients perform is to act as antioxidants, which protect the body from harmful unstable oxygen molecules, known as free radicals. While free radicals occur naturally in the body but are also produced in response to cigarette smoke, pollution, pesticides, and excessive sunlight. If allowed to roam loose in the body, free radicals can damage DNA, certain cell structures, and cell membranes. But antioxidants can capture these destructive agents by chemically combining with them and making them harmless. The best way to obtain antioxidants is through foods (like fruits, salads, vegetables, but also whole grains and vegetable oils too), and not from supplements unless your doctor prescribes them.
My practical nutrition suggestion -You can also fill up on the fiber by eating more fruits and vegetables. Many of us need more roughage or fiber in our diets. Fibre refers to carbohydrates that cannot be digested and, therefore, provide no calories. Because fiber “fills you up, not out,” it helps you to manage your weight better. Eating more fibre also means you have less room for high-calorie nibbles throughout the day!