This question has puzzled me for long. My family does consume non-veg but we don't do it on Mondays and Thursdays and also not on full moon days. Also we only consume mostly meat and fish. So why is it like this ? Why some particular sects/castes have high resistance for non-veg consumption and others are very liberal; given that both follow hinduism and practice the same rituals in the exact same way. What does our vedas/puranas say about this ? I vaguely remember bhagwad-geeta mentioning three types of food: satvik, raajsik and taamsik. Non-veg i believe falls in taamsik and is considered to be the worst.