It could be a detox reaction. Cayce had a three day apple fast that is pretty intense, Christopher has a prune juice and apple juice fast for removing excess mucus that can also create weakness and other detox symptoms. Just don't overdo it. Experiment until you find how much fresh applesauce you can manage without feeling weak. I agree fresh raw applesauce is a wonderful thing and healthy too. You get minerals, pectin to help cleanse the bowel, anti-oxidants and good taste.