Over-eating can be both a matter of sheer greed, or quite definitely an addiction, and if it's the latter then it's hard to break irrespective of whether the individual is intelligent or stupid. The urge to overeat in a stressful situation is a physical reaction to the hormonal changes brought about by stress/emotional turmoil. Willpower can overcome pure greed, but when overeating results from emotional difficulties, willpower alone is not enough, and support needs to come from other people and in many different forms to try to re-educate those who do suffer this way to change their behaviour. There is abundant evidence of the overeating/weight gain problem among older women who themselves have caring responsibilities for even older relatives, usually their parents. As a woman in my late 60s caring for a mother in her early 90s who has multiple medical problems and advanced dementia, I speak from experience of my own weight gain of 2 stone since being in the stressful caring role, and that of many other women in the same position.