My Web site and blog are about healthy food. I want people to know what science really says about how diet affects human health. For example, we know that eating animal-based foods raises the risk of a whole host of diseases, including heart disease, many cancers, and autoimmune diseases. The less animal-based food you eat, the safer you can be from those diseases. So the health-optimizing diet for human beings would be free from animal products. It could therefore be classified as vegan. Although all healthy foods are vegan, not all vegan foods are healthy. For example, no one would consider bourbon and potato chips to be the basis for a healthy diet.
The first vegetarians I met were vegetarian for religious reasons. They included some Hindu people who had been born in India and some Seventh-Day Adventists from the USA. I’ve also known observant Jews who would eat in vegetarian restaurants because everything that’s vegetarian is automatically Kosher. I also know a lot of people who refuse for moral reasons to eat any products that come from animals. All of the people I’ve just described can eat at my house without violating any of their dietary laws. Since I’m allergic to wheat, everything that I cook is even kosher for Passover. However, not everything that passes muster in their dietary laws is good for them.
To be truly health-optimizing for the average person, a diet also has to be low in fat (<10% of calories) and high in fiber. Some of the foods that contain no animal products are nevertheless high in fat or low in fiber. A high-fat, low-fiber vegan diet could promote atherosclerosis, even though it doesn’t contain any cholesterol. That’s why even vegans occasionally die of heart attacks.
When I was growing up, I was taught in school that the meat group (which includes eggs and fish) and the dairy group (which includes all milk products) are an essential part of a balanced diet for human beings. However, when I grew up and started reading nutrition and medical textbooks and scientific journals, I found strong evidence that those foods are dangerous and unnecessary. So far, I haven’t found any evidence that any human beings would really benefit from adding animal-based foods to an otherwise healthy plant-based diet. I found plenty of evidence that cats need certain nutrients that occur only in animals, and are not produced by plants or bacteria. However, I’ve seen no such evidence for human nutrition. If I find it, I will report it. Then, the decision of whether to eat those foods will be a moral decision, not a health decision.