Hmm, ok. First off, let me say that I won't judge you at all for eating meat. I'm not an ethical vegan -- my reasons are about 90% for health, and 10% for environmental concerns. It's weird, but it's only after becoming vegan that I've started to care a bit more about animal welfare -- prior to that it was like "I'm not totally comfortable with the fact that animals have to die to provide me with meat, but it's very tasty, and I'm good at compartmentalizing". It would be very hypocritical of me to criticize anyone else for this reason.

I should also note, that I follow a whole-food, plant based diet, which is both stricter than a typical vegan diet in some ways, and less strict in others. I don't obsess so much if I have a bit of honey, or if my food has touched some meat, or anything like that. But I try pretty hard to stick to "whole foods", which rules out "vegan junk food", and in fact most processed foods, which have added oil, salt, and sugar, and have fiber and valuable phytonutrients stripped out. The fact that I don't eat anything with processed oil means that it's really quite hard for me to eat so much that I gain fat. I believe the term "nutritarian" is another way to describe this diet. (But of course, I cheat once in a while).

I sort of agree with you about people doing best on different diets, but in a more limited sense than you mean, I think. For sure, nuts and avocados have a lot of research showing their health benefits -- but I don't eat them, because every time I do I feel like crap for the next day or so (which is SUPER annoying, because I fucking love avocado). Whole wheat is healthy, unless you have Crohn's disease.

I think that some people who feel better without carbs might feel better because they eliminated a particular chemical that comes along with certain types of carbs, without realizing what the exact culprit was. Someone who suffers from a dairy intolerance and drinks milk every day, might actually feel better after switching to an all-beef diet, even though they cut out tons of healthy foods!

But overall, I think that the general shape of the healthiest human diet is virtually all plant foods, with most calories from carbohydrates rather than animal protein and fats. In exceptional cases like childhood epilepsy, ketogenic diets can be valuable, but there is a long list of undesirable side effects -- it's just that it's better than the alternative. And the Standard American Diet is so bad that pretty much any deviation from it is an improvement.

I don't want to try to convince you that you should stop eating meat because I want to prove that I'm right, or something... It's more that I wish that everyone can be happy and healthy, and I based on what I've learned in the past few years of geeking out on nutrition research, I suspect that though you feel better on a high-animal-protein diet, it might be causing you (and most other people) long-term harm. And that there might be a diet that works for you both in terms of long-term health and also just plain feeling good.

But I understand that it's really hard to try to eat something that you expect to make you feel unwell. I 100% understand if you are happy enough with this diet not to want to make any more changes.

I guess, just, maybe if down the line you find that you're suffering from high blood pressure, or heart disease, or pre-diabetes, or just start feeling unwell, you might remember our conversation and consider giving a plant-based diet another try. Maybe at first just by swapping in some beans in the place of meat, fish, or eggs (they're not terribly high-carb), and gradually trying out other foods.

By the way, if you don't eat a particular food and then suddenly start eating it, it can take a while for your gut bacteria to adjust. Different types of foods require completely different bacteria to digest them, and the lack of the right type of bacteria can cause the food to just ferment in your intestines, which feels pretty bad and leads to smelly farts. It's best to make dietary changes slowly.

Also, it's possible to eat a low-carb vegan diet, with most of the calories coming from plant-based oils. It takes some planning though.

And the fact that you eat vegetables, fruit, nuts, and avoid trans fats and other junk food is a step up from the standard american diet, for sure.

Oh, and finally: IGF-1 is a growth hormone, you're correct. The reason it leads to cancer is that when you get more of it than your body naturally produces, by eating meat, it stimulates the production of new blood vessels. Tumors need a lot more nutrients than normal tissue to support their growth rate, and IGF-1 gives them that -- without it, they have a much harder time.

We are actually getting little cancers all the time, but our body is quite good at killing them, if avoid foods that help the cancer and eat lots of foods that with anti-cancer chemicals (cruciferous vegetables, for example). If our immune system couldn't fight most of the little cancers, we'd be in some pretty serious trouble.

Anyway, I wish you the best of health and happiness! Thank you for your honest and thoughtful discussion.