G’day Leasrel, Where are you from?
Yes the key to overwintering bees is food; stores of Honey and Pollen. If the bees do not have enough food left from the season or were not able to produce enough due to bad weather, then the bees need to be fed.
There is some dispute over feeds and Sugar water, Fondant patties and Pollen patties are often used.
Personally I would be wary of Pollen patties if the Pollen is from a source that is not irradiated; as they can be a transfer of disease. Also some Fondants are made with Corn syrup and this can be from GM crops.
If you make your own Fodant it is recommended not to add Acid - Cream of Tartar (Tartaric Acid), vinegar etc as it can cause the sugar to become HMF
here is the link to the discussion