I am a vegan There is nothing strict about it I don't eat the flesh of innocent animals or dairy/eggs which involves the killing of the males. I don't eat GMO foods.
I don't find anything strict about this since I have no appetite for dead flesh or food laced with carcinogenic herbicides.
I find refusing food which is involved in violence not strict but liberating. I can look a cow in the eye and say a friendly "moo." The strictest diets are based on addictions, such as the addiction to meat. Meat eaters say all the time "I have to have meat."
That is a compulsion, which means they are on a strict diet, demanding meat.
The major studies (Loma Linda, Oxford, and China) over several generations and involving hundreds of thousands shows a vegetarian diet leads to a longer, healthier life. That is not strictness but freedom.