Please go on, Sir.
So, it seems that those who did business outside the parish or otherwise interacted economically with others on a more regional scale (such as this innkeeper) tended to prosper. They had a more varied and healthy diet. Perhaps in your travels, you observed that the Burghs or towns had a greater variety of economic activity than the strictly rural, isolated fermtouns and small villages such as Lesmahagow. My guess is that the Burgh business was financed through an assortment of rents, court fines, market customs and tolls. With lots of money in circulation, I suppose then that all would live healthier lives in these more economically vibrant towns. Let's ask an expert how the wealth was allocated in the larger towns.
(1) Greenshields, Annals of Lesmahagow, p. 274-5.