Starvation

Starvation or Hunger, displayed as FOD, is a derived statistic in Fallout: New Vegas in Hardcore Mode.

Characteristics
occurs if the player does not eat food over a long enough period of time. It accumulates slowly at all times, and primarily affects Strength, though Perception and Charisma also suffer at higher starvation levels. It takes five days for the player to starve without eating anything. Most types of food will reduce starvation by some amount, though certain foods are more effective than others.