Paper towels soak up water because they are made up of cellulose fibers that are loosely woven together. This not only attracts water but makes it easy for water to travel through, trapping the water inside the paper towel.
The cellulose fibers in the paper towel are made of sugar molecules. This is the key to why paper towels are so absorbent. When a paper towel comes into contact with a wet surface, the water molecules cling to the sugar molecules.
Although the cellulose fibers make it easy to store water inside a paper towel, it is also easy to remove some of the water from a paper towel by ringing it out. The process of compacting the paper towel causes the loosely woven fibers to become more compact, forcing the water back out of the paper towel.
Just because the cellulose fibers inside a paper towel are made up of sugar molecules does not mean that a paper towel is edible. Humans lack the necessary enzymes that are needed to split cellulose molecules apart. This makes it impossible for the human body to separate the individual sugar molecules. As a result, paper towels hold no nutritional value upon consumption.