Thanks to Internet we can find many places where exists lot of information about food, and the importance of each group of food. Visitthese websites and learn as much as you can!
http://endrino.cnice.mecd.es/~jgol0025/
Here you can see how are called some foodstuffs.
http://www.saberingles.com.ar/lists/ifruit.html
In this website you can find the name of some fruit and vegetables.
http://www.learnenglish.de/vocabulary/foodmeat.htm
This web will help you with some fish and meat vocabulary
http://www.nutritionexplorations.org/kids/nutrition/pyramid-grain.asp
Here you will have information and vocabulary about grain group.
http://www.nutritionexplorations.org/kids/nutrition/pyramid-veggie.asp
This other will help you with the vegetables group.
http://www.nutritionexplorations.org/kids/nutrition/pyramid-fruit.asp
This link will show you all about the fruit group.
http://www.nutritionexplorations.org/kids/nutrition/pyramid-milk.asp
Thanks to this link your doubts about the milk group will be answer.
http://www.nutritionexplorations.org/kids/nutrition/pyramid-meat.asp
The next link explains all you need to know about the meat group
http://www.nutritionexplorations.org/kids/activities-main.asp
And finally in this website you will enjoy and learn byplaying some games.