The best resource for nutrition that I have found is this book:

How not to die by Dr. Greger (https://www.amazon.com/How-Not-Die-Discover-Scientifically/dp/B016CME5B4)

It contains a review of essentially all the nutrition studies published in the last 10-15 years. In a nutshell, a healthy diet consists of a large amount of unprocessed, plant-based foods, including vegetables, mushrooms, nuts, seeds, legumes, whole grains and fruits. In addition, a healthy diet consists of eating a variety of these foods so that the full spectrum of nutrients can be absorbed.