Some supplements can u003ca href=u0022https://www.health.harvard.edu/staying-healthy/breaking-the-fastu0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003ebreak your fastu003c/au003e. It depends on what you're fasting for. If you're fasting for weight loss, supplements that are less than 500 calories are safe to have. However, if you're fasting for gut health, you want to steer clear of any supplements that will activate your digestive tract.u003cbr/u003e