Does olive oil break a fast?

A tablespoon of olive oil (13.5 g, 15 ml) has about 120 kcal. A teaspoon has about 40 kcal. Olive oil is almost pure fat, with no sugar or starch.

The site rates each item against four goals of its own design. For weight loss, a tablespoon breaks the fast, at more than twice the 50-calorie line. That line is a common rule of thumb, not an official limit. Any calories break an autophagy fast. Fat has to be digested, so a spoonful of oil breaks a gut-rest fast too.

Blood sugar is the one goal olive oil passes. With no sugar or starch, it does not raise blood glucose the way fruit or a sweet drink does. A morning spoonful of olive oil still ends the fast for the other three goals. Some people add oil to a fast to feel full for longer, and those calories still count against weight loss.

As a worked example, one teaspoon stirred into a morning drink is about 40 kcal. That is under the 50-calorie line, so a single teaspoon is a grey area for weight loss. Two teaspoons are about 80 kcal and break a weight-loss fast. Measure the oil with a spoon, because a free pour from the bottle is easy to misjudge.

Olive oil fits best in your eating window, in cooking, on a salad or in the meal that breaks your fast. Cooking oils are all about 120 to 130 kcal per tablespoon. MCT oil, at about 130 kcal, breaks a weight-loss fast for the same reason.