Food will be translated into heat for your dog and your dog will use the food to build a healthy fur coat with which to keep warm. It doesn't take much of a coat to provide a lot of warmth for a dog. Even a Lab Retriever with a 1cm coat can keep warm but if your dog is a very short coated breed, like a Dalmation, outside temperatures may be too cold. Also be aware that areas of coat that may be shaved or skin conditions that have resulted in loss of hair coat may be particularly prone to frost bite. IL clipped and sutured a wound on the side of a dog just before the last arctic outflow, and the dog received frost bite over the clipped area when the weather changed.
Water is a difficult item to keep in supply during arctic outflow.
You will need to continuously add water to your dog's bucket since it will freeze up in less than 30 minutes. Having a water heater is nice but many dogs will chew at the electric cord so be careful. Snow will not provide the needed water for your dog. It takes too much snow and melting snow in the mouth and stomach will cause hypothermia. You should also curtail some of the normal walks during very cold weather.