Yellow grapefruit are yellow on the outside and a paler yellow on the inside. They are sour to taste. They are round and about the size of a softball. Storage These grapefruits can be stored at room temperature for a week or up to two weeks in the fridge. Nutrition Grapefruit have a fat burning enzyme that makes them great for weight loss. Yellow grapefruit are also an excellent source of Vitamin C ? just half a grapefruit provides 80% of an adults daily needs. Grapefruit are high in dietary fibre, contain no fat and can help lower bad cholesterol. Ideal Use Yellow grapefruit are not great to eat as is, due to their sour taste. To reap the health benefits, while still having it taste sweet, a recipe favourite is to cut it in half, sprinkle with brown sugar and serve with Greek yogurt.