Does chia seeds break a fast?

A tablespoon of dried chia seeds weighs about 12 g and has about 58 kcal. It holds about 3.7 g of fat, 2 g of protein and 5 g of carbohydrate, and about 4 g of that carbohydrate is fibre. Two tablespoons come to about 117 kcal, and a 28 g (1 oz) serving to about 138 kcal.

On the four goals this site uses to sort answers, chia seeds break a fast for weight loss, autophagy and gut rest. A tablespoon is over the common 50-calorie rule of thumb, which is not an official limit. Autophagy is the strictest goal, and chia has both calories and protein. The seeds and their fibre are food your gut has to digest, so gut rest is broken too.

Blood sugar is a grey area. Only about 1 g of the carbohydrate in a tablespoon is not fibre, so there is little to raise blood glucose. Chia is still a food with fat and protein, though, so it does not count as fasting for any goal on this site.

Chia water is sometimes sold as a fasting drink. Soaking the seeds in water does not remove any of their calories. A glass made with one tablespoon still has about 58 kcal. Chia pudding made with milk, fruit or honey adds more, since a tablespoon of honey alone is about 64 kcal of sugar.

Chia seeds fit well inside your eating window. They work as part of the meal that breaks your fast, along with protein and other foods, instead of as something to sip while fasting.