Being a doctor is stressful and people cope with it in a couple different ways, some personalities double down on the stress and power through it, most doctors are that type. Other people turn to drugs, alcohol, distractions, or food to cope and get away from their stress. Most of that type wash-out of medical school but a few make it through, hence how you have fats in a high-stress field constantly overeating despite knowing how bad it is.