Another consideration that was briefly mentioned is national/world diets. With the increase of free trade since WW2 people have gotten bigger. Even in regions that historically had little lean guys. I remember reading (many years ago) that the average height in Japan post WW2 increased dramatically. Mostly due to diet changes. It seems to be support by a study I found. "Just this month came the news that Japan's long-forecast demographic implosion has finally begun to materialize in the form of the smallest class entering elementary school since the statistics were first kept, in 1946. But lost in the gloomy news, and even ignored by many here, is one measurement by which the reputedly diminutive Japanese have been closing the gap impressively with Westerners: height. In 50 years, according to statistics kept by the Ministry of Education, the average height of Japanese 11-year-olds has increased by more than 5 1/2 inches. The height of girls, who grow faster at that age, meanwhile, has increased even more. So far, there has been no definitive explanation for the increased growth, but it is widely believed to be caused by improvements in diet and the elimination of once-common infectious diseases, both expressions of Japan's swift postwar economic rise. According to one recent study, for instance, intake of animal protein has doubled to 60 grams a day since 1960. " http://www.nytimes.com/2001/02/01/world/tokyo-journal-the-japanese-it-seems-are-outgrowing-japan.html With the increased availability of high quality foodstuffs worldwide people seem to be reaching their genetic possibilities. Also it is cool to see big beefy guys do explosive things.