Food can also be entangled with loneliness and depression in that those who suffer through loneliness will eat more for the comfort it brings. A depressed individual will already have lowered executive function which will lead to giving in to the temptation of eating which provides comfort through massaging the esophagus, the same type of comfort we could also derive from a social connection where touching occurs on some level.
Self regulation can be impaired due to loneliness and or depression and have nothing whatsoever to do with how strong someone's will is or notions of personal responsibility.
In one study using three groups, one group was told that they were the type that others loved to be around and that they were most likely to marry and have many friends in life according to the results of a test, another group was informed that they were most likely to end up alone, unable to maintain social relationships, they might get married but would divorce each time, and the third group of the study were made to believe that they fell in the category of those who would have accidents later in life even if they have not had many.
One part of the study had them rating cookies. Instructions were to eat only as many as needed to judge accurately. Those with a forecast of loneliness ate twice as many as those who were promised friends. They also rated them higher but even when they did not they kept eating.
Loneliness can also affect intelligence:
Effects of Social Exclusion on Cognitive Processes : Anticipated Aloneness Reduces Intelligent Thought