If someone were to choose only one type of food to eat for the rest of their life, it would ideally need to be nutritionally balanced to sustain them. A diet primarily consisting of a variety of fruits, vegetables, lean proteins, and whole grains would be the healthiest option. However, it's important to note that no single food can provide all the necessary nutrients, so a varied diet is essential for good health. Eating only one type of food for an extended period is not recommended and could lead to nutritional deficiencies and health issues.