There is no one food that has all the ingredients we need. If we eat a wide variety, we ensure that we get sufficient of all the vitamins and minerals that our bodies require. There is some evidence that eating a little of a lot of different foods greatly reduces the chances of developing food allergies. This applies particularly to the main starch foods so don't eat wheat and potatoes all the time.
"Which Way to Health" recommends that you eat as much as you like of fruit and vegetables. Your target should be five portions a day. They're full of vitamins and fibre, but low in calories. Don't worry too much about pesticides in or on fruit: for most of us, heart disease is a much bigger risk. If you are worried, buy organic, or grow your own.
In the UK the highest incidence of heart disease occurs in the people who eat the least fruit and vegetables. The more fruit and vegetables you eat, the less likely you are to develop cancer of the lung, stomach, mouth, cervix, colon or rectum.