I didn't see a lot of fat people while I was in Africa. Maybe it's got something to do with politics. If you're an evil colonialist, God curses your kith and kin to obesity as a way of redress. Then again, I note that many African despots and dictators past and present were fat. Hmmmm.
One question I have: Has obesity gone up in the States in the past few decades? I do not believe in all this low fat food and people thinking that as long as they keep the fatty food low- they can eat carbohydrates all they want. You gotta eat fat to be healthy, you gotta eat fat to keep from being obese (what I mean is a balanced diet at least 20% calories from fat/20% protein/the rest in simple and complex carbs). I believe it is a fairly recent trend- obesity in America and has just as much to do with our affluence and diet as anything else.
Check out the website, www.udoerasmus.com. It has alot of good information about both the good oils(unprocessed and protected oils, like fresh Omega 3 aand Omega 6 containing oils and virgin olive oil) and the bad oils (any processed or refined oils).
I highly recommend reading his book on the subject, Fats That Heal Fats That Kill. LOTS of great information on our health and how important the essential fatty acids Omega 3 and 6 are in our diets.