I found a great nutrition site by Metagenics, a science-based nutrition and supplement company with a goal to improve lives. On their site, along with the nutrition products, they have provided a nice overview of nutrition basics, titled Nutrition 101.
Check it out: http://www.metagenics.com/knowledge-center/nutrition-101
Metagenics believes the right nutrition could help people realize their best health possible by positively influencing what makes them unique—their genes. They call it realizing “genetic potential” for good health. Today, it’s known as the science of nutrigenomics — the study of food as one of the most important environmental modifiers of gene expression in determining health and disease patterns.
Through their ongoing commitment to nutrigenomic research, they’ve been able to identify natural compounds with powerful therapeutic applications, to be used in our science-based TLC programs, medical foods , and nutraceuticals.