Here are some valid reasons to become a pescetarian (a pescetarian is someone who eats fish or invertebrate seafood but no other kind of meat) : Health : red meat is high in saturated fat and (regardless of whether it's lean or grass fed) has been linked with colon cancer due to high levels of nitrosamines. Even skinless chicken has been linked with bladder cancer due to high levels of heterocyclic amines. Ethical: Health wise, there is nothing wrong with fully skimmed cow milk or cooked egg whites but buying these products supports the poultry and live stock industries which are cruel to non-human animals and bad for the environment as a whole. In theory, eating products that come from cows and chickens isn't as cruel as actually eating those cows or chickens but the methods that slaughterhouses use to mass produce milk and eggs are cruel and merciless. Cows are often milked until they literally drop dead from exhaustion, chickens are crammed into tight cages where they are surrounded by dead chickens and fecal matter and unnatural methods are used to get them to produce an unnatural amount of eggs ( conditions may or may not be less cruel for free-range chickens but this is how it is for factory farmed chickens). The conditions of cows, pigs and chickens in slaughterhouses are unimaginably cruel and harsh ( and, based on neuroanatomy, there is as much evidence for non-human mammals and birds being sentient as there is for other human beings being sentient). I recommend a short documentary called 'meet your meat' which you can find on youtube. If a being is capable of pain and suffering, belonging to a less intelligent species is irrelevant, pain is pain. After all, many non-human animals have a higher degree of self-awareness or cognitive ability than human infants or some mentally retarded humans do, why should we not give them the same rights and considerations that we give to those less intelligent humans? As for the 'animals eat us' argument, the non-human animals we eat are non-threatening. They are either herbivores or too small to be a threat to us. For good reason, we usually don't domesticate animals that are a threat to us because they are a threat to us but if we managed to do so, they would be tamed (and thus, harmless). Truly compassionate people aren't selective with who they are compassionate towards, it doesn't matter whether or not a non-human animal has the same moral code that we have (compassion and altruism aren't actually exclusively human traits, they are found in other species as well) Environmental : we waste a lot of grains feeding cows, pigs and, to a lesser extent, chickens and fish, that could be used to feed other humans instead. In the U.S, up to 70% of all grains are used to feed livestock and a similarly high percentage of land and fresh water is used for meat production as well. Livestock production is responsible for up to 18% of all greenhouse gas emissions (don't think that Black people won't be seriously affected by global warming or that the Caribbean and sub-saharan Africa wouldn't benefit if the West were to stop wasting precious resources on meat production). Case for eating fish or invertebrate seafood : Ethical: fish and most invertebrates (with the possible exception of cephalopods) lack a true cerebral cortex or anything analogous to a cerebral cortex so it's very unlikely that they are sentient (capable of subjective experience). (If I ever come across convincing evidence, based on neuroanatomy and not just behavior, that fish and crustaceans are probably sentient, I will give up seafood as well, regardless of how healthy it is. I don't care whether or not eating meat is 'natural' either.) Health : seafood is our only true source of some omega three fatty acids (DHA and EPA). The omega three fatty acid (ALA) found in plant sources like walnuts, flax etc. cannot efficiently convert into DHA or EPA. Meat and animal products are our only natural source of B12 and studies have shown that vitamins and minerals from natural sources are healthier than synthesized nutrients. If you do eat fish, you should try to buy wild fish instead of factory farmed fish. Factory farmed fish are fed grains and aren't as healthy as wild fish are, they have lower amounts of omega three fatty acids. They may also be pumped with antibiotics, like cows, pigs and chickens in slaughterhouses are. Not only is factory farmed fish less healthy than wild fish is but, again, the grains used to feed large amounts of fish could feed hungry humans instead.