Here are some reliable resources that will give a basic overview, as well as detailed information, about nutrition. For additional information look at books, journals & magazines, and newspapers & websites. 

1. Dietary Guidelines for Americans (Health.gov): https://health.gov/dietaryguidelines/
2. Healthy Eating Style, Choose My Plate (USDA): https://www.myplate.gov/
3. Healthy Eating (American Heart Association): http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Healthy-Eating_UCM_001188_SubHomePage.jsp
4. Eat Right (Academy of Nutrition and Dietetics): http://www.eatright.org/