I think we're seeing multiple factors with a kind of hideous synergy: 1) Decrease in physical activity (desk jobs, social media, games, an endless stream of en

I think we're seeing multiple factors with a kind of hideous synergy: 1) Decrease in physical activity (desk jobs, social media, games, an endless stream of entertainment). 2) Federal subsidies causing a glut of some foods. 3) Increased portion sizes on many things. 4) Forever chemicals, the PFASs, xenoestrogens, bisphenols in many things we touch or what touches our food, messing with our hormones. 5) Hormone-fed livestock for weight gain, does any of that pass on to us? 6) Supranormal stimulation: we're eating and drinking things designed to stimulate us at a level we just weren't evolved to deal with. 7) Real changes in food composition -- as an example, consider the shift from cane sugar to HFCS. I think that's the most of them. So, imagine each one of them caused a teensy one percent change (caloric intake, increase in digestion efficiency, whatever). Well, that's 1.01 to the power of our seven different factors, or, if you would originally be stable at two thousand calories per day, an extra 144 calories per day. That's about a can of Coke. Doesn't sound like a lot. However, that adds up to 52,596 extra calories per annum, or a fifteen pound gain. Hideous synergy.