Chris Kresser is a hack and should not be giving out nutritional advice. Unfortunately it is drivel like this that causes so much of the confusion regarding nutrition.ThisDinosaur wrote: ↑Tue May 16, 2017 12:03 amhttps://chriskresser.com/why-you-should ... gan-diets/
Vegan diets lack a lot of essential nutrients that humans cannot make without consuming animals. Many plants actually contain antinutrients that inhibit absorption of specific micronutrients.
Cholesterol is an essential building block of every one of your cells. Its also necessary for making steroid hormones, like testosterone and estrogen. Fortunately, your body can make cholesterol out of glucose. In fact, you are much more likely to develope high cholesterol on a high calorie, high carbohydrate diet than you are on a low calorie, high fat diet. In other words, being overweight and out of shape can raise your blood cholesterol levels regardless of the specifics of your diet.
Michael, is there anything that would change your mind about the perfect diet? Not that its important for me to change your mind, I'm just curious if anything would.
Regarding B12, B12 comes from bacteria in dirt. The reason that we cannot easily get B12 easily in our diet is because we wash our food. Often, animal products contain B12 because the animals themselves were given B12 supplements (injections). This is an easy vitamin to supplement for cheap, and is the only thing that vegans should look specifically at.
There is plenty of calcium in green vegetables which you should be eating plenty of every day. It is easy to consume plant-based products that have fortified calcium. Likewise, there is plenty of iron and zinc in beans and legumes. EPA and DHA are fairly cheap and easy to supplement using algae based supplements and this is recommended if one doesn't consume fish (in fact, these supplements are able to avoid contaminants contained in fish oil products). ALA to DHA and EPA conversion is weak in humans and there is good benefit, particularly for your brain, in supplementing these. None of the vitamins are found exclusively in omnivorous diets. In fact, it is laughable that Chris claims that vitamins A-D are difficult to get from plants and this really highlights how he is pushing an agenda and not paying careful attention to nutritional science. The only additional supplement that I would recommend here is vitamin D3 (which can be sourced vegan from lichens). Vitamin D is produced by your body from sun exposure, so this recommendation has nothing to do with your diet and everything to do with your sun exposure.
Everything else about that article is wrong. He argues that while populational studies show that vegetarians and vegans are healthier, that this is causally attributable to their general disposition to live healthier (i.e. to not smoke and to exercise). He does not provide any evidence that this is the case, and what might be an otherwise reasonable point completely disintegrates when you recognize that animal fat is the primary cause of atherosclerosis, the precursor to heart and cardiovascular disease. Yes, the "essential" dietary cholesterol that comes from animal products is not only synthesized in our own bodies, but causes significant cardiovascular problems if consumed in excess. The ideal intake for dietary cholesterol is zero. There is also good reason to believe that animal protein (IGF-1 is the culprit) increases risk for cancers. I haven't even considered the issues of hormone or heavy metal contaminants in any detail (and I'm not the expert that should be consulted in any case).
This is easily available from the literature, and the fact that Chris makes arguments from holism in order to discredit populational studies and mechanistic data, and the fact that he relies on tired arguments about B12 in order to discredit veganism, shows his intellectual dishonesty. Every respected nutritional organization recognizes that veganism can be perfectly healthy for all stages of life. Yeah, you're going to have to pay some attention to where you source your nutrients from with a vegan diet if you want to approach optimality, but this is true for any diet.
Finally, I want to point out that the "evolutionary" reasoning typical of paleo diet pushers is a horrible and increasingly ubiquitous kind of reasoning. Is Chris Kresser seriously suggesting that he knows anything about the evolution of human metabolism and how this relates to optimal dietary intake (which need not closely resemble the predominant diet of our ancestors)? Has he ever done any serious research in his life? Take a look at some criticism of evolutionary psychology (yes, the entire field of study). It turns out that it is not very difficult at all to come up with plausible evolutionary "just-so stories" that can be used to push any preconceived view about functions in biology. Anybody who uses this kind of reasoning without hard evidence should be seen as highly suspect.
I often wonder what ethics would look like if we were different creatures (but were still intelligent). What if we were carnivores? What if we had a reproductive cycle more similar to hive insects? What if we relied on the slavery of members of other sentient species, or even our own (hint: we did)? Fortunately for me, as of the time that I am writing this, there are strong ethical, ecological and health-based arguments that all point in the exact same direction: veganism. For intellectually honest folk there are many nuances in reasoning required when considering ethics, ecology, human health and specifically how all of these things relate and should ultimately guide our actions. Many of these nuances can be completely avoided by becoming vegan. In my experience, nearly all of the arguments against veganism can be reduced to selfish hedonism. If you have any interest in ethics or civic responsibility, I can tell you first hand that it is relieving to recognize that you don't have to choose between these things and your personal health. Get yourself some vegan B12, D3 and EPA-DHA supplements and follow the new four food groups daily intake guide. A cursory search for a source for these supplements and a few changes in your pantry/recipe book is all that is needed, and it will put you ahead of almost every other human in terms of achieving a diet that is optimal for health. If you have fitness goals, look closer at getting more protein in through your diet, and supplement a vegan protein powder for whatever the remainder might be. Easy.