Here are some useful websites:
1) The FDA website, Food section: https://www.fda.gov/food
2) The food and nutrition website of the Canadian authorities: https://www.canada.ca/en/services/health/food-nutrition.html
Some interesting readings:
I don't necessarily endorse everything in these publications, but I do find them interesting
1) Robbins G. The Food Revolution. 2010. ISBN: 9781573244879
2) Campbell, TC. The China Study: Startling Implications for Diet, Weight Loss, And Long-term Health. BenBella Books. 2006. ISBN: 9781932100662
3) Bredesen D, Perlmutter D. The End of Alzheimer's: The First Program to Prevent and Reverse Cognitive Decline. Avery. 2017. ISBN: 9780735216204
4) Perlmutter D. The Grain Brain Whole Life Plan: Boost Brain Performance, Lose Weight, and Achieve Optimal Health. Little, Brown Spark. 2016. ISBN: 9780316319195
5) Davis M. Eat Your Vitamins. Your Guide to Using Natural Foods to Get the Vitamins, Minerals, and Nutrients Your Body Needs. Adams Media. 2020. ISBN: 9781507211359
And some instructive videos:
Here as well, I don't necessarily endorse everything, but I find it interesting
1) The documentary "Fork Over Knives": https://www.youtube.com/watch?v=EjTWFoqLy34
2) Interview with Charlotte Gerson, the daughter of the controversial Max Gerson, who nevertheless has the merit of putting her finger on the importance of diet and the limits of allopathic medicine: https://www.youtube.com/watch?v=2uVyj6fSSjM