From what I've been researching...it seems people since at least early written history, all the way up until world war 2, consumed 3500 calories or more a day, including soldiers and slaves. Mideval peasants ate 3500-4500 calories a day, slaves in America averaged 4500calorie a day ration, colonial soldiers at least 3200 calories, roman soldiers ate 3500 to 6000 calories a day. How is it that people in the old days with less technology ate much more high quality, all organic, fresher, more local food than we do today, and also had little to no problems with obesity...it was basically unheard of. What's the determining factor? Obviously it isn't calories, and grain made up the majority of everyone diet except for maybe british or French nobility as far as I can tell (who coincidentally were the highest likely to be overweight)