Hi I was wondering what the various roles of each of the following nutrients are and what happens if you are to have too little or too much of each:

1. Calories
2. Protein
3. Carbohydrates
4. Sugar
5. Fat
6. Saturated Fat
7. Fibre
8. Salt

Thanks for any help.

There's loads of informative websites out there that describe the roles of nutrients and what effect too much/little of them can have on you. Try looking in a search engine...