Enhanced Vigor (5e Feat)
From D&D Wiki
Prerequisites: Constitution 13 or higher
You have trained your body to endure the extremes of adventuring and harsh environments, conferring the following benefits:
Your Constitution increases by 1 to a maximum of 20
You can now re-roll one Constitution saving throw. You must do this before the DM tells you if the roll was a success, and must take the second roll. You regain the ability to do this at the end of your next long rest.
You now only require half the food and water that a creature of your size would generally require.