I sometimes think of it this way:
- are there vegans in Africa? Where food is scarce, do African make such decisions?
- since the beginning of time, what did the first people eat?
Of course there are. Africa is a huge continent, not some far off jungle or desert with a few bush people

I am African and I am vegetarian, almost vegan. In fact, in the parts of Africa I'm sure you're thinking about, the villages live mostly on crops and sometimes fish.
To answer your second question, the American Dietetic Association notes that "most of mankind for most of human history has lived on vegetarian or near-vegetarian diets."
Here are my reasons for not eating flesh:
Meat consumption has quadrupled in the last 50 years and the meat industry is the number one cause of global warming. A 10 acre farm can support 60 people growing soybeans, 24 people growing wheat, 10 people growing corn, but only two producing cattle. Studies have also shown that vegetarians actually get a more optimal amount of protein and it is easier to digest than animal protein. Animal protein on the other hand comes with all of the growth hormones, antibiotics, dioxins, and a plethora of other drugs that are fed to animals in order salve the unnatural conditions of factory farming.
Factory farming is the number one cause of water pollution in the world! As well as number one cause of air pollution, and number one cause of loss of biodiversity. Furthermore, the pollution and greenhouse gases produced from factory farming are 40% more destructive than all transportation on Earth combined.. and we all know what a fuss they make about gas emissions from vehicles!
Meat-eaters: have claws
Herbivores: no claws
Humans: no claws
Meat-eaters: have no skin pores and perspire through the tongue
Herbivores: perspire through skin pores
Humans: perspire through skin pores
Meat-eaters: have sharp front teeth for tearing, with no flat molar teeth for grinding
Herbivores: no sharp front teeth, but flat rear molars for grinding
Humans: no sharp front teeth, but flat rear molars for grinding
Meat-eaters: have intestinal tract that is only 3 times their body length so that rapidly decaying meat can pass through quickly
Herbivores: have intestinal tract 10-12 times their body length.
Humans: have intestinal tract 10-12 times their body length.
Meat-eaters: have strong hydrochloric acid in stomach to digest meat
Herbivores: have stomach acid that is 20 times weaker than that of a meat-eater
Humans: have stomach acid that is 20 times weaker than that of a meat-eater
Meat-eaters: salivary glands in mouth not needed to pre-digest grains and fruits.
Herbivores: well-developed salivary glands which are necessary to pre-digest grains and fruits
Humans: well-developed salivary glands, which are necessary to pre-digest, grains and fruits
Meat-eaters: have acid saliva with no enzyme ptyalin to pre-digest grains
Herbivores: have alkaline saliva with ptyalin to pre-digest grains
Humans: have alkaline saliva with ptyalin to pre-digest grains
Since we cannot digest meat in the intended the way carnivores can, we have rampant heart disease, hypertension, and colon and other cancers. In the colon, undigested proteins putrefy, undigested carbohydrates ferment, and undigested fats turn rancid. This causes toxicity, and these toxins then seep through the intestinal wall and get into the blood stream, which eventually leads to even more health problems.
And my most simple reason of all.. I wouldn't want an animal to eat me, so I don't eat them.
