Burn
Get Burn
Burn
Get Burn
HOME / GUIDES / DO SUPPLEMENTS BREAK A FAST
Two questions decide it. Does it carry calories, and does it need food to be absorbed? The first affects the fast. The second affects whether the supplement works.
A run through the common ones, and the timing question behind them.
QUESTION ONE
A plain capsule or tablet carries essentially none. A gummy, a chewable, a flavored powder or a liquid in a syrup base usually does, and amino acids are the clearest signal you can send that food has arrived.
This is the question that decides whether the fast continues.
QUESTION TWO
Fat-soluble vitamins are absorbed better alongside dietary fat, so taking them fasted is not harmful but is less effective. Some minerals are also harsher on an empty stomach.
This one does not affect the fast at all. It decides whether you are wasting the supplement.
The common ones
Two columns, because the answers are different: whether it breaks the fast, and when it is best taken.
The practical answer
This settles both questions at once. Nothing to weigh up about the fast, and the fat-soluble vitamins actually get absorbed. In practice that means taking them with the first meal instead of first thing in the morning.
Sodium, potassium and magnesium belong during the fast, since that is when you are losing them. A calorie-free form is the one to use.
Medication timed to meals should never be moved to fit a fasting schedule. Speak to your doctor before changing when you take anything prescribed.
How strict to be
A fish oil capsule and a protein shake are not the same question, and neither is a 16:8 and a three day fast.
A capsule with a few calories in it will not decide anything. Total energy across the day and whether you keep the pattern going are what matter, so take the vitamin and move on.
Past 24 hours the point is an uninterrupted stretch without food, so keep it to water, salt, plain electrolytes, black coffee and plain tea.
Burn times the fast you tell it you are running and names the stage the clock has reached. It does not detect what you took, and it does not measure ketosis, autophagy, or metabolic state.
That fat-soluble vitamins are absorbed better in the presence of dietary fat is well established, as is the role of amino acids in signaling nutrient availability. Claims are drawn from peer-reviewed research and traced in our evidence policy.
Burn does not recommend supplements or doses, and nothing here replaces advice from your own doctor or pharmacist. Anyone taking prescribed medication, managing a health condition, or pregnant should get advice before changing what they take or when.
Burn tracks sodium, potassium and magnesium next to your water and every fast you run.
Download free on the App StoreiPhone, iPad, and Apple Watch. Requires iOS 18 or watchOS 11.