Experts say eating a range of fruit and vegetables is best, as part of a balanced diet, to protect against illness. Research suggests eating at least seven portions( 一份 ) of fruit and vegetables a day is more effective at preventing disease than the government's current five-a-day recommendation. Is five a day enough? Yes—but people should eat at least five portions of fruit and vegetables a day, the government says. The advice is based on World Health Organization guidelines, which are 25 years old. Experts say eating five portions a day is enough to get the protective benefits of fruit and vegetables although eating more may be additionally beneficial. What counts as a portion? Fruit juice counts towards one portion of the recommended five portions per day. For an adult, a minimum of 400g of fruit and vegetables should be eaten every day, or five portions of 80g. The amount is different for children, based on activity levels and age, but a rough guide is that one portion should fit in the palm( 手掌 ) of their hand. Fruit and vegetables do not have to be eaten on their own and can be cooked in dishes such as soups and other meals. Experts suggest that only taking in enough nutrition can we be healthy. That is to say, we must eat enough fruit and vegetables every day. 6 . What is the main idea of the passage?