Malabsorptive surgeries limit the quantity of food that the body can digest and absorb.  These types of procedures, such as biliopancreatic diversion, involve a reduction in the length of the digestive tract.  By shortening the small intestines, the body will digest and absorb less food, thereby decreasing caloric intake and promoting weight loss.  Malabsorptive operations are the least often performed weight loss surgeries today.