Chew every bite of food well till it becomes paste-like before you swallow. Our great grandparents advised this as there's a scientific reason behind it.
Because your stomach does not have teeth. 80% digestion happens in your mouth. Food particles become fine like paste and mix well with saliva. Saliva is in itself a digestive enzyme.
Paste instead of solid particles also increases the surface area of food particles so that hydrochloric acid & saliva together in your stomach can act better for optimum digestion. Food, when not chewed well, leads to constipation, weight gain and generates AMA.