The U.S. adult population in the 1970s ate an average of 2400 calories a day. By the 2000s, our calories were up to 2900.
What did average adult weight do as we increased daily calories by 500? Increased by 8.6 kg, from 72.2 to 80.6 kg. In U.S. units, that’s a 19 lb gain, from 159 to 178 lb.
Children increased their average intake by 350 cals/day over the same time frame.
If I recall correctly, I’ve seen other research suggesting the daily calorie consumption increase has been more like 150 to 350 per day (lower end for women, higher for men).
Details are in the American Journal of Clinical Nutrition.
The study authors don’t say for sure why we’re eating more, but offhand mention an “obesogenic food environment.” They don’t think decreased physical activity is the cause of our weight gain; we’re fatter because we eat too much.
h/t Ivor Goodbody
Worth saying this is disputed but…simple explanation of obesity epidemic may be we eat 500 cals more than in 1970s http://t.co/k3RQnIdCGn
— Ivor Goodbody (@IvorGoodbody) May 22, 2014