The books of Adelle Davis (https://en.wikipedia.org/wiki/Adelle_Davis). Writing in the mid-20th century, she was way ahead of her time. She's just as relevant now as she ever was.
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).