every morning, there is a ~33-50% chance that your hunger multiplier increases by +0.2 for the rest of the day (heightened cravings). This rolls twice independently, so there is a ~11-25% chance to get +0.4 (intense cravings).
if you started the day with 5 leaves and smoked at least once before 16:00, you can use the additional leaf that you get at 16:00 (unlocked by achievement) and smoke 6 leaves in 1 day. with this and the previous cravings mechanic, the maximum hunger multiplier is 4.6