Not all , but most..I've seen some nasty looking lean Tongans and Sa's.Bastards are designed to be elite in the sport of bodybuilding but they dont have a clue. 
It takes no real smarts for bodybuilding, lift weights, eat right and diet. At my old gym there were several polys there, big as shit brick houses and stronger than He-Man. But they were fat as hell and breathed hard when they walked. Young as well. I believed that over centuries that their bodies got used to the fatty foods on the islands (palm milk is HIGHLY fatty), plus certain cultures stigmas, helped create huge and highly fat individuals, they are not really stronger than anybody, or this would have already exploited in the Olympic Games or Strong Man Comps, they would be winning everything.
Or track and field for that matter. As for bodybuilding, it's harder for people who are naturally fat to get to that elite levl of conditioning. This is why The Rock, who is half black half Somoan had to get lipo, and why MattT's vapiric bodybuilder friend, who is half black half Somoan as well, has a hard time Getting in condition as well, he should know since he is after all 500 yrs old. Tevitei had issues with it, Sonny schmidt accomplished it, but, he didn't have the genes to really compe with the vest