The Food and Drug Administration (FDA) does not consider cellulose (or virgin wood pulp) to be hazardous for human consumption and sets no limit on how much can be used in food products. Virgin wood pulp is processed into cellulose gum, powdered cellulose, and other materials, which are used to make pet litter, asphalt, detergents, and plastics. It is also used in fast food and the industrialized food production system as a filler in puddings and baked goods as well as ice creams and crackers. What nutritional benefit is there to adding cellulose to food? Do you feel it is ethical for the FDA to set no limits on how much cellulose can be added to your food?
Cellulose has no nutritional benefit.
http://www.ukfoodguide.net/e460.htm
Uses in food are given in the link above. This is for the UK , USA regulations will be different and probably less strict.