Am substituting cheese, frozen ices and yogurt. could this cause lactose intolerance?

Yes.: Any cheese you buy should be devoid of carbohydrate, but your lucky: swiss, chedder, colby, provolone, parmesgan, romano, etc. Avoid american processed chees. (read the lable-carbs which are lactose). Frozen ices and most yogurts contain lactose. Greek and middle eastern style yogurts may contain little to none. But check the carbs-lactose, unless sweetened with corn syrup & dextrose.