The ideal diet for most people is a low-fat, low-salt, whole plant based diet. This diet avoids excess dairy, meat, salt, sugar, oil, fat, refined carbohydrates, and food additives. The expert I trust most is Dr. Neal Barnard. His dietary recommendations are supported by many other respected researchers including:
Dr. Dean Ornish
Professort T. Colin Campbell
Dr. Caldwell Esselstyn, Jr.
Dr. Joel Fuhrman
Dr. John McDougall
The whole plant based diet includes leafy greens, colorful vegetables, legumes, whole grains, fruit, ground flax seed, and supplements of B12 and D as needed. Animal proteins tend to be very hard on the kidneys, and most humans can survive very well on plant based proteins alone that are supplied by legumes, whole grains, vegetables, and leafy greens. The healthiest populations in the world do not consume animal based foods or use animal based foods in very limited quantities for flavoring.
Most of the experts and authors I listed also publish cook books. I like the latest one published by Dr. Neal Barnard. Former president Bill Clinton announced that he adopted a whole plant based diet and lost 24 pounds and reversed his heart disease. (This was at Esselstyn's recommendation) It's also useful in helping reverse type II diabetes, and kidney failures. Excess animal proteins are hard on the kidneys.
This diet is also ideal for healthy individuals.