The Digestion adaptation is the second adaptation unlocked in the game. It allows the player to safely consume alien life forms without sustaining a deduction to their health bar.
If a player without this adaptation attempts to eat an alien lifeform, regardless of if it is cooked or not, the player will not receive any of the item's effects on either the Hydration or Food bar and instead, will be deducted health.
Method of Obtaining
In order to obtain the Digestion adaptation, the player must make their way to the Angel Comb located right above Anita Gottschall's Blackbox, and around 160 meters at 22.5° from the Lifepod. After arriving at the Angel Comb's location, the player can interact with the Gene Donor in order to be granted the Adaptation. The player will then be able to eat alien fauna and receive their nutritional benefits without taking damage.

Databank Entry
Life in this unknown ocean shares its basic genetic code with Earth. DNA letters code for amino acid words, which are joined into strings like sentences to create proteins. Pioneers can also look forward to familiar delights such as sugar, starch, fat, and alcohol.
However, this world's genetic code uses different words for amino acids, creating waxy and metallic proteins. Human stomach enzymes cannot digest them. Undigested mass builds up in the intestines, causing indigestion, intestinal blockage, starvation and gout.
This field adaptation allows your digestive tract to secrete alien enzymes built with human chemistry. Borrowing these enzymes bypasses the need to design a synthetic equivalent — allowing you to proceed with the mission. The chances of your digestive tract digesting itself are minimal.
Source: Acquire the Digestion Adaptation
Trivia
- Alien life forms that give a deduction in either the Food or Hydration bar will not grant the effect after being eaten by a player which does not possess the Digestion Adaptation.