They found that chubby men in their prime were generally relaxed about life whereas underweight or obese young women under 45 were significantly more likely to have poor mental health.
More recent research has found that children in Scotland have less healthy lifestyles than children elsewhere so maybe not a good population to study?
Although Dickens wrote about cheerful portly characters such as Samuel Pickwick, and Tony Weller the coachman, he also knew of the health risks including gout. Mr Weller said it arose from “too much comfort and ease“. He didn’t actually say get up and do some exercise preferring to recommend marrying a widow with a loud voice but you get the message. Do something about it!