The English character (explaining the rise of Empire) might be explained (by Shakespeare):
Give them great meals of beef and iron and steel, they will eat like wolves and fight like devils.
Warriors are not vegetarians. Beef is concentrated energy, so is iron and steel (from coal). The results are armed warriors who need to fight. When the beef and coal starts to run out, so will the number of warriors. The remaining warriors will fight more ruthlessly for the remaining beef and coal. Etc.