Consider two identical 50-kg women, Candy and Wendy, who are doing identical things and eating identical food

Question:

Consider two identical 50-kg women, Candy and Wendy, who are doing identical things and eating identical food except that Candy eats her baked potato with four teaspoons of butter while Wendy eats hers plain every evening. Determine the difference in the weights of Candy and Wendy after one year.