Thanks for a very interesting and pertinent question.
The basis of a diet style which promotes health and longevity is one that contains high levels of micronutrients, phytochemicals, fiber, and other health promoting compounds. The best foods for accomplishing this are green leafy vegetables (kale, collard greens, spinach, lettuce, etc.), cruciferous vegetables (broccoli, cabbage, cauliflower), berries, beans, mushrooms, onion, nuts and seeds. Filling the diet with these elements gives one the ingredients that the body needs to function optimally, and to help us to really feel energetic and well.
So…those are the foods that will keep us the healthiest. But what about meat? Can one have a healthy diet that includes meats? There are no studies that suggest that a small consumption of some types of animal products is detrimental to health in the presence of lots of fiber filled plant foods. Likewise, there is no evidence that an animal free diet is deficient in any element that the body needs to function at its peak. (the only exception is Vitamin B12 which vegans need to supplement. It is not made by animals, only eaten in their diet, and then passed on to the human consuming the meat product)
What are the safe meats and in what amounts? Dr. Fuhrman suggests for those wanting to keep meats in the diet, they should be minimized to perhaps 1.5 ounces per day as a flavoring to foods-like a condiment. No more than 10 ounces per week. He states that calories from animal products should be kept below 5% of your total daily intake. While he does not recommend animal products in general, he suggests that if we are going to eat any animal products, that we choose fat free dairy products and white meat fowl, fish or eggs. Avoid processed, barbecued or cured meats.
Thanks again for a great question!