Psst: It's the food, guys

StrategyPage has an article on China's military, that includes this:

February 24, 2014:  The Chinese military has noticed that current recruit are larger than those of two decades ago. On average the current recruits are 20mm (.8 inch) taller and 50mm (two inches) larger at the waist. Designers of military equipment have been ordered to adjust the design of vehicles and other equipment to reflect this. This sort of thing is not unique to China....
 

This growth is one of the side effects of affluence. Prosperity does many things, one of the more obvious effects is to make children and grandchildren of those who started the economic boom obviously larger. More food, especially more meat, makes children grow larger. This was first observed during the 1980s in Japan where many family photos, which included three generations, revealed dramatic differences in the height of each generation. Those who grew up before World War II were noticeably smaller than those born in the 1950s when the food supply was more regular and more abundant than before the war. The kids born in the 1970s were, as adolescents, larger than their parents and towered over their grandparents. Now it’s happening to China, which experienced food shortages throughout the 20^th century. This did not begin to improve until the late 1970s. Now many affluent Chinese have to worry about obesity.