While consuming marine collagen may slightly impair autophagy, it shouldn’t significantly affect ketosis or fat burning during a fast (1).
Each 1.5 TBSP serving of our North Atlantic marine collagen contains only 30 calories and 0 carbs (and therefore a glycemic index of 0). Since our marine collagen is hydrolyzed, the protein is essentially pre-digested, meaning it's easily absorbed and requires very little to no work for the digestive system.
For this reason, many customers, and members of the Landish team, love adding our marine collagen to their morning routine to get the benefits of both intermittent fasting and collagen.
Referenced sources:
Cai, Chen-Chen, Zhu, J, et al. (2019). Glycine Protects against Hypoxic-Ischemic Brain Injury by Regulating Mitochondria-Mediated Autophagy via the AMPK Pathway.