Humans don't taste that good anyways, not speaking from personal experience.
Humans are typically omnivores that don't eat healthy so they aren't going to taste that good.
If you're going to eat another human you need to get one that eats healthy. Vegetarians and vegans would be the ideal choice. Barring those, someone from a strict religious group like the Amish or some Mormons sects probably have less toxins in their bodies.
Also don't eat the brain, bone marrow or spinal fluid. It would be bad.
Also generally try to avoid drinkers, as they tend to fuck up their livers, which can be harmful. Also make sure you shave and rinse your victim's entire body before cooking. Not only does this keep hair from being in your food, it also allows you to eat the skin, which will crackle and peel similar to chicken and has nutritional value. Although I'm told the meat is different depending on age. Example, kids are more like veal, whereas older folk are more like tough roast. My advice? Target the vegans. Nobody likes them, people would probably cheer you for killing them if (most likely when) you got caught, there's less chance of contamination, and it's wonderfully ironic.