my son weight is not gaining his waight is same from last 6-7 months plz suggest me something to gain his weight. His current weight is 8.9kg and it is same from last 6-7 months

A. Provide a variety of age appropriate foods over three meals and two to three snacks per day. Choose higher fat cuts of meat (rib eye, T-bone, medium ground beef), dark meat from chicken and fatty fish like salmon. Use whole milk, cheese, cream and yogurt (3% M.F. or higher).