Perplexing Botswana Observation #586

I know I haven't blogged about the previous 585 perplexing observations but, trust me, I have made them and will get around to sharing them eventually (I have two years so fret not friendly followers)! Perplexing Botswana observation #586 is purely dietary. It is this: the Batswana diet consists almost entirely of carbs and starches (in large quantities) and they put massive amounts of mayo and ketchup (mixed together) as dressings on said carbs and starches. And yet somehow, completely out of my realm of understanding, they are not massively obese. In fact, I have seen some of the skinniest people in my entire life walking the paths of my village. It is remarkable and utterly perplexing. If someone can explain this phenomenon to me please speak up. In the three months I have been here, I have most certainly gained weight. I want in on whatever the Batswana have going for them!