"People survived quite well in harsh climates, the most notable being the Inuit, without much in the way of vegetables at all, and no grains or fruit. It wasn't until peoples like the Inuit adopted a more industrialized diet that they got diabetes and heart disease." -adkpam

You are correct in that the Inuit ate mostly meat but there is a big difference between the meat they ate (mostly fish and whale meat) and the meat we tend to eat on Atkins (like beef, sausage, pork, etc.) The meat we tend to eat is very high in saturated fat while whale meat is high in fat, but not in saturated fat, so it will not clog arteries the way our pig and cow meat might. Saturated fat dries as more of a solid substance, contributing to the clogging of arteries while unsaturated fat dries as more of a liquid. The Inuit also put out a lot of physical activity, burning off much of the calories from fat they consumed by expending a lot of energy. The average lifespan was about 60 (common before modern medicine). Having said this, I still think Atkins or low carb CAN be the healthiest way to eat, depending on how you do it. The people who assume we eat meat and cheese all day long are right to say that that is unhealthy. I, however, eat meat, cheese, eggs, vegetables, salad, nuts, occasional fruit and yogurt and low carb milk and cereal. That way of eating sure beats my old habits of candy, burgers, fries, pizza, burritos, soda, ice cream, etc. So the answer to this question depends on HOW the person is following the low carb lifestyle.