Does quitting non veg have benefits?

Why do many astrologers ask people to stop eating non veg? Does quitting non veg indeed have positive effect on life?

Why many also claim vegan diet is best and suggest plant based diet as panacea for everything from PCOD, PMDD, dysmenorrhea to even speech disorders or claim plant based diet is anti ageing?

Why ayurvedic doctors and yoga practitioners also generally prescribe vegetarian diet?

Does purely vegetarian diet or vegan diet and removing animal based products and meat from diet, have positive effects for real?

Animal products may contain whatever was fed to the animal: hormones and antibiotics that will perturb your endocrine system and the microbiota of your digestive tract. Some pathogens that infect animals may cause disease in humans because we are also animals. Properly cooking meat and eggs kills pathogenic bacteria, but if the bacteria are allowed to grow first, the toxin molecules released by them can still cause disease.

You may also want to avoid the cruelty, methane emissions, and wasted energy associated with meat and dairy products.

If you choose a vegetarian lifestyle, you should plan your diet to include reliable sources of vitamin B12 and vitamin D hormone. If you don't get enough sun exposure, your body itself will not make enough vitamin D hormone, and so you will need it in your diet. Plant-based foods are not reliable sources of these two vitamins, which is why you may need eggs or dairy products in your diet.