I believe that all of these questions should be closed as primarily opinion-based because there are just too many problems with questions of this form. (Of course, the question author should be encouraged to improve the question before it's closed.)
- The idea of healthfulness is ambiguous; it may refer to either quality of life (vitality) or duration of life (longevity) and those questions don't always share the same answers.
- What is healthy for an individual depends on their goals. For example, some people are trying to gain weight, while others are trying to lose it, and they would probably not eat all the same foods.
- What is healthy also depends on individual physiology. Some people are allergic to kiwifruit, so for them they would probably consider kiwifruit to be unhealthy.
- Healthfulness also depends on quantity. Water is important for vitality and longevity, but drinking too much water too quickly can be fatal. Eating fruit sometimes is often considered healthy; but eating only fruit usually isn't.
However, there are some good questions about being healthy, so I'm not trying to say that every question using the word "healthy" should be closed.
