Does coconut water break a fast?

Coconut water is the clear liquid from inside a coconut. A 240 ml (8 fl oz) cup has about 45 kcal and 6 g of natural sugar. The same cup has about 600 mg of potassium and 250 mg of sodium. The sugar decides the answer for most fasting goals.

This site sorts answers by four goals. Coconut water breaks a fast for blood sugar, because 6 g of sugar raises blood glucose. Coconut water also breaks a fast for autophagy and gut rest, since anything with calories counts for those stricter goals. For weight loss, a single cup is a grey area. At about 45 kcal, a cup sits a little under the common 50-calorie rule of thumb, which is not an official limit.

The carton size changes the weight-loss answer. Coconut water has about 19 kcal per 100 ml, so a 330 ml carton has about 63 kcal and 9 g of sugar. A 500 ml bottle has about 95 kcal and 13 g of sugar. Either size goes over the rule of thumb, so a whole carton breaks a weight-loss fast as well.

The potassium and sodium in coconut water can make it look like a fasting drink. During a fast, an unsweetened electrolyte mix gives you sodium and potassium without the sugar. Save coconut water for your eating window, where its sugar and calories count as part of your food for the day. If you take insulin or a sulfonylurea for diabetes, talk to your doctor before fasting at all. Follow your diabetes team's advice on sugary drinks.