[1] https://www.nhlbi.nih.gov/health/educational/wecan/tools-res...
[2] https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...
NUTR101x - Nutrition and Health: Macronutrients and Overnutrition
"For anyone who is interested in the relation between nutrition and health and wants to acquire the skills to better weigh and interpret the information overload about nutrition and health."
This is a free, self-paced course by WageningenX and hosted by edX.
[1] http://sigmanutrition.com/ [2] http://sigmanutrition.com/blog/ [3] http://sigmanutrition.com/recommended-resources-2/
She had detractors (and I'm sure someone here will be quick to point them out). Just ignore them and read her best known book Let's Eat Right To Keep Fit: it's an excellent and comprehensive introduction to nutrition.
The final chapters go beyond nutrition - they're a manifesto for building glowing health, first starting with oneself, then family, and finally society; all on a foundation of good soil and sound agriculture. They truly instill a sense of infectious hope and optimism. You'll want to be a soil scientist, or farmer, or nutritionist. Even the references lead one on to the ideas of permaculture, before the term was even invented.
How Not to Die by Dr. Michael Greger is another superb book (mentioned by others here).
Spoiler alert: all of the videos can be summed up by: "eat a whole food, plant based diet".
As a general note though - nutrition as a science is _hard_, because everyone responds slightly differently to the same foods in unexpected ways, and it's really hard to do double blind, controlled trials over a long period of time (they cost too much, or are just unfeasible). So I think the best approach is to read/watch a lot of different content from different sources, in order to gain a wide understanding of the current research.
Patrick Holford is considered by many as a goto know all for holistic nutrition https://www.patrickholford.com/
