High Metabolism (3.5e Flaw)
From D&D Wiki
 High Metabolism [General]
You burn calories at a greater rate than average, though you gain no additional weight from such consumption.
Effect: You require twice the amount of daily food for a creature of your size and begin to feel the effects of starvation in half the time a normal creature would.
Benefit: You receive a bonus feat.
Roleplaying Ideas: Characters with high metabolisms might often find themselves munching on something or other during inappropriate times. While not a manic compulsion, characters with this flaw should keep their hunger in their back of their minds and likely seek out at least one or two snacks in the middle of the day, outside of their main meal. When they do sit to eat a full meal, they will likely do so with great haste and hunger (especially if they haven't had a snack).