Both Regina and Stephan have some good commentary on this recent study:
Daily energy expenditure and cardiovascular risk in Masai, rural and urban Bantu Tanzanians
Regina's first post is really worth reading here
Here we have evidence that a high-fat, low-carbohydrate diet, consumed habitually does not lead to obesity, high blood pressure and dyslipidemia, and it may, in fact, lead to beneficial long-term health and increased levels of activity in those habitually eating such a diet.She also comes back to the topic here.
there is a simple explanation for why the Masai do not develop atherosclerosis despite consuming a high-fat diet that the authors did not consider: high-fat diets (not containing man-made fats) are not atherogenic.
Stephan also examines the study really helpfully in this post: What to do if your study contradicts conventional wisdom.