Fish oil is a grey area. A capsule contains a small amount of fat and around 10 to 40 calories, so it technically breaks a strict fast, but it does not raise insulin and has little metabolic impact.
| Calories | ~10-40 kcal per serving |
|---|---|
| Breaks a weight-loss fast? | Partial |
| Breaks ketosis? | No |
| Breaks autophagy? | Yes |
| Insulin impact | None |
Fish oil is pure fat, so it does not raise insulin or break ketosis. But it does carry calories, typically 10 to 40 per serving depending on the dose, which means it breaks a fast defined strictly by calories or by autophagy. For practical fat-loss fasting its impact is tiny; for a clean autophagy fast it is best taken with food.
If your fast is about insulin and fat loss, a fish oil capsule is essentially irrelevant. If you are chasing autophagy, take it with your first meal instead. Fat-soluble supplements like fish oil are also absorbed better with food.
A standard one to two capsule dose is negligible on a fat-loss fast; for a clean autophagy fast, take it with your first meal.
FastTrack times your fasts, your eating window and your progress, with a plan built around your goals.
Get your free plan