Try out the following method, did some tweeks and is working fine for me now! :)
-(UINavigationBar*)insertTopbar
{
UINavigationBar *navBar = [ [UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
UINavigationItem *navAdd = [UINavigationItem alloc];
navAdd.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem: UIBarButtonSystemItemAdd target:self action:@selector(addFood)];
[navBar pushNavigationItem:navAdd animated:YES];
navBar.topItem.title = @"MyApp";
return navBar;
}