improve code for nested foreach loop

Hi Experts,
I have following code and it will take too much time with my average data. than how can i improve it. Please give me suggestion.
foreach (var c in lstMyMaster { obj = new MyCustomizeModel(); obj.AId = c.id.ToString(); obj.AName = c.title; obj.AType = ActivityType.P1;//Static class const string obj.PAId = parentPlanId.ToString();//int id obj.Ownr = Convert.ToBoolean(c.Ownr); obj = GetMonthWiseData(obj, c.Money);//function obj.M1 = c.M1; obj.CreatedBy = c.createdBy; obj.isEditable = false; model.Add(obj);//model is list of MyCustomizeModel type parentId = c.id.ToString(); foreach (var p in c.programs) { ...