Why is it that black girls tend to have thicker thighs?

Fast twitch muscles. Although the kenyans, who are also African, don't have very well developed ones which is why they make better long distance runners.

Black girls tend to have rounder asses and thicker thighs (Western African descent ones) because the fat distribution is different to other races. They are also more muscular in those areas. They have less peripheral fat which is why they can appear to have lean/musular torsos and very slim calves/arms/wrists and ankles.
Africa has a long history of relatively dry and hot climate and so the periods of starvation and famine would be more likely to be longer. In order to store fat for lean times in the least harmful way (abdominal fat has the highest risk for heart attacks, cardiovasular disease), black people have evolved to store their fat mainly on the ass and thighs as the fat is less mobile in the bloodstream and less likely to cause cardiovasular disease. For this reason, black people can often be heavier and carry a little more fat with less risk of developing obesity related illnesses than, say white or asian people, because of the fat distribution. Of course there black people with big stomachs and white people with thick thighs. In this case it's the fat distribution that is protective not the colour, but more black/latino people tend to fall into that category than white or asian people.

(I remember studying this when I was doing Nutrition and Physiology. Apologies for lack of sources, but I finsihed the course 3 years ago and cant be arsed- no pun intended- rooting though my files)

OOOOUUUAAAAAHHHH!!

What?

Food. Eat eat eat. Love it.

Unfortunately the stereotype about black men doesn't apply to alot of them. Me included.

Eating loads does not mean you'll have thick thighs though. It just makes you fat everywhere.

Yes, very true about the black man stereotype not being true. While there might be more of those with very extreme size, the majority are in the middle. The middle is a good place though. Don't knock the middle.

Eat + exercise = Nicest arse/thighs on the planet. It's a shame girls of other races (white) rarely do this.

ouch! Thats uncalled for, man!
I see quite a few caucasian girls with a full bum and thighs and some flat arsed black girls in the gym. It's more in the genes to fill them jeans though.

they have smaller tits though

thats a lie, im black and my tits are certainly not small in fact they are quiet the oppossite

there are exceptions to the rule eg. nicki minaj. It's so rare to find a girl who's really packing in both.

well i guess im an exception then...and my friend lol

Looking discusting is an opinion, however my point was that black girls havent all got thick thighs and round asses..

they have smaller tits though

I'm a D cup at 43 kg.... And that's from my grandma who's fully black and was a lot bigger etc.