This thread has produced some good and thoughtful debate. I'd like to throw another food related topic into the discussion, the gut biome. All our food is digested in our gut, partly by the enzymes released but also by the billions of bacteria that live in the gut. The products of bacterial fermentation are re-adsorbed and play a vital part of our nutrition.
Before I talk about the gut biome a last though on a vegan diet. Humans cannot source sufficient of the following from a Vegan Diet, unless the vegan person is very careful to ensure blood levels are maintained by taking supplements and in some cases eating plant based foods that have other side effects.
Vitamin B12. Vitamin D (actually even carnivores can be deficient as they need sunlight to make it) Long Chain Omega 3 fatty acids. Iodine Iron Calcium Zinc
Well-planned vegan diets can fulfil nutrition needs for all stages of life. That said, certain nutrient requirements may be difficult to achieve through diet and fortified foods alone.
This is especially true for vitamin B12, vitamin D and long-chain omega-3s. All vegans unable to meet their dietary recommendations through diet alone should seriously consider taking supplements. Unfortunately for Vegans some of the supplements are animal based extracts... And a lot of medicines contain non vegan components.
The composition of our gut flora evolves, quite rapidly, to take best advantage of the food we eat. It can be destroyed by antibiotics and it has been suggested that the obesity crisis we see today is as much to do with a compromised gut biome as the food we eat. I read a paper recently that suggested that artificial sweeteners used in "zero calorie" drinks cause humans to feel thirsty, so drinking more. The only safe zero calorie drink is water.
My take on all this is that we must feed ourselves and our gut bacteria with unprocessed food, prepared as needed. If we want to eat animal products then we have a duty of care to the animals that provide the foods.
We should try to reduce food miles, although it can be difficult to fully understand the CO2 burden inherent in food miles. For example the CO2 burden from tomatoes grown in hot houses in the Netherlands and the UK is actually higher than the CO2 from trucking tomatoes from Spain.
Use common sense, eat what works for you and enjoy life!!
Lots of wisdom and knowledge there Peter. Best summed up in a quote from Michael Pollan: "Eat real food, not too much, mostly plants."
