Currently, the government does not charge the HST on basic groceries - meat, dairy, fruits, and vegetables - but does on things like snack foods and prepared foods that are not necessarily as healthy for you. The reason for this is to encourage healthier diet choices.
My suggestion is that the HST for all food products at grocery or similar stores should be included in the price, rather than just applied at the cash register. This way, consumers will see this price differential on the store shelf when they are making the decision about what to buy rather than just when they get to the cash register.
To be clear, this wouldn't increase the price of any of the products, just include the cost of the tax they are already going to pay for the product in the price tag earlier on in the shopping experience in order to nudge consumers to make healthier choices.