Artificial lighting can bugger your circadian rhythm. It can also contribute to depression, which contributes to eating for some people who don't know a better way. Being tired from buggered sleeping habits contributes to obesity as it decreases your metabolism and will also help make them less likely to want to do anything active. The junk they binge on compounds all of that and it's a positive feedback loop. The drugs they get prescribed are fuel on the fire. But it's all wonderful for the economy.