I have noticed that among philosophers, vegetarianism of one form or another is quite common. In fact, I became a vegetarian (technically a pescetarian) myself partly out of respect for an undergraduate philosophy professor. I am interested in finding out if there is a similar disproportion in the Less Wrong community.
I didn't request that this go into Yvain's survey because I want more information than just what animal products you do or don't eat; I'd also like to see nuances of the reasons behind your diet. There are a lot more shades than carnivore/vegetarian/vegan - if you want to be a vegetarian but are allergic to soy and gluten, that's a compelling reason to diversify protein sources, for instance. I'd also like to hear about if you avoid any plant foods (if you think they're farmed in a way that's environmentally destructive or that hurts people or if you have warm fuzzy feelings for plants, maybe). Here are some questions that come to mind:
- What foods, if any, do you normally avoid for reasons other than pure culinary taste, cost, individual health concerns (allergies, diabetes, etc.) or ease of preparation? (Avoiding foods that are considered revolting or just non-food in your culture of origin, like balut or fried locusts, counts as "culinary taste".)
- What are your reasons for avoiding those foods?
- How strictly do you avoid them? For instance, will you eat them if you are served them while a guest at a meal, or if you are hungry and there is nothing else available? Do you check to see if they're in potentially questionable dishes at restaurants (and if so, do you trust what the server says?)
- If you have children or plan to have children, will you expect or encourage them to avoid the same foods?
- Do you try to convince your friends and family members to make dietary choices similar to yours? If so, have you ever succeeded?
- If you avoid a class of foods with valuable nutritive content (as opposed to Twinkies), what do you replace it with to get complete nutrition?
- What are your attitudes to people who are more restrictive in their diets than you are? Less restrictive?
- What is the timeline of your dietary restrictions? (Transitions, lapses, increases or decreases in restrictiveness, etc.)
- If you have not avoided these foods for your entire life, how much did you enjoy them when you ate them, and do you still sometimes want to eat them?
- Is there anything else about your choice of diet that might be relevant or interesting?
I've mentioned Good Calories, Bad Calories here before and it is a pretty comprehensive overview of the research. It's also an interesting read as an example of how science and rationality can go wrong when politics and special interests get involved.
I'm not aware of any large scale studies that have done direct controlled studies of the kind of diet I'm describing. Dietary studies are notoriously difficult and expensive which is one of the problems with dietary research discussed in the book. The results from a variety of different studies and nutritional research are persuasive though. I'd suggest reading the book for far more detail than I can give here.
Dietary choices are generally trade offs - if you reduce calorie intake from one source you generally have to substitute calories from elsewhere. There is evidence that polyunsaturated fats from many vegetable oils can lead to higher incidences of cancer. Studies have failed to confirm the hypothesis that saturated fats cause heart disease. There is increasing evidence that sugar and refined carbohydrates are primary factors in obesity, heart disease, cancer and diabetes. Substituting refined carbohydrates for fats seems to be a bad idea from a health perspective and it is difficult to obtain adequate calories from unrefined carbohydrates alone. Given that some level of fat intake seems necessary to achieve adequate calories, I'm persuaded that increasing the relative proportion of animal fats to vegetable oils in my diet is beneficial. The fact that that balance better fits my personal taste preferences means that my evidence threshold to make that change is lower than it might be for others.
Polyunsaturated fats aren't great, but monosaturated fats, like olive or canola oils, are healthful. Those two oils and animal-derived milkfat and fat from eggs constitute about 90% of the fat in my diet (the rest is incidental, like the fat in avocados, or shortening in some baked goods).