The Inuit (in Greenland, Canada, Alaska) eat meat-only diets and they are healthy.
The Inuit communities were not healthy. Inuit mummies had high rates of atherosclerosis at 60%, and osteoporosis. This was before they had any Western influence.
Inuit life expectancy was very low at 43.5 years compared to neighboring countries.
Inuit did eat plants: berries, seaweed, and a variety of other plants.
For more on a meat-only diet, see this fun video.

Topic: FAQ – Health