Marijuana or weed consumption increases the appetite and the appetite is researched to be more for sweets over other tastes.The effect together is not yet clearly established. If someone took weed only once, he/she need not worry so much about long term effects because it is clear that neither there is physiological nor psychological addiction which alters the functioning of body and mind in long run. However psychological factors like guilt & fear of the alter effects in the long run need to be left behind just the way weed was left behind after one experience.