Fish oil won't break a fast because it contains no calories or digestible carbohydrates. However, it may temporarily disrupt autophagy, a cellular cleanup process that occurs during fasting.
Intermittent fasting creates a caloric deficit that triggers autophagy, where cells remove damaged components. This process begins after 12-16 hours without food, depending on the individual.
Fish oil contains omega-3 fatty acids, which the body can metabolize. While it doesn't provide calories from carbohydrates or protein, it may still pause autophagy temporarily. The body prioritizes processing these fats over cellular cleanup.
Some intermittent fasters consume fish oil during their fasting window to maintain ketone levels. Ketones support energy production without breaking the fast. However, this practice may reduce autophagy benefits temporarily.
These supplements provide essential nutrients without impacting blood sugar or insulin levels. However, excessive amounts of any supplement may disrupt fasting benefits.
I've tested this firsthand during a 24-hour fast. After taking fish oil, my ketone levels rose slightly, but I noticed reduced hunger suppression compared to fasting without supplements.
Fish oil won't break a fast due to its lack of calories, but it may temporarily pause autophagy. If maintaining autophagy is your goal, avoid fish oil during fasting windows. For other fasting-friendly supplements, consider electrolytes or vitamin D.