i dont think veganism is an acceptable diet
however i do believe in the power of limiting the diet to restorative foods and would suggest a healing diet with NO fruits, NO NUTS OR SEEDS, low glycemic carbs is acceptable as a healing treatment for those with extremely compromised systems and only to be used for short periods of times, the focus being on major amounts of greens(mostly fresh lettuces, dandelions, mallows and smaller amounts of kales, cabbages, arugula, mustards which i believe should be stewed) large of fresh parsley(curly, italian) cilantro, dill, fennel, basil, as well as herbal teas made with roots, seeds and leaves, nourishing and restoring veggies such as cukes, zukes, okra, onions, garlic, leeks, small amounts of cooked root veggies, baked squash, baked or souped potatoes, and that all of this should be taken with butter, salt and lemon or lime. mostly just making it a green nutritious soupy healing diet and also believe in fermented veggies in lieu of yogurt...i think then adding fats and meat in the form of broths and organs, then fish and white meats, yogurts and eggs, and then red meats, once all of this is tolerated you can add peas, berries, melons, citrus and honey in small amounts if tolerated........thats kind of a culmination of my observations and experiences personally and that of friends and acquaintances....
i dont think veganism is sustainable, complimentary measures such as vitamins and other chemical compounds means that your diet is lacking, body is not absorbing properly, needs time to heal, needs more nutrition from powerful food and probably more sunshine and fresh air and less of the social burdens that impart sickness on all of society