Question 1

What is the best time to take multivitamins?

Accepted Answer

The best time to take a multivitamin depends on the type, as fat-soluble components—such as vitamins A, D, E, and K—are better absorbed with food, making your eating window the most common approach.

Fat-soluble vitamins require dietary fat to be properly absorbed by your body (4). While water-soluble components, like B vitamins and vitamin C (5), can be taken on an empty stomach, grouping them together during a meal is often easier to remember.

Many people find that taking a multivitamin with food also reduces the chance of digestive discomfort. If you are practicing intermittent fasting, scheduling your multivitamin alongside your first or last meal of the day is a practical way to support your routine while ensuring you get the most out of your supplements.

Question 2

Do vitamins have calories?

Accepted Answer

Most vitamins and mineral supplements are calorie-free or contain negligible calories. Standard tablet multivitamins, water-soluble vitamins, and basic electrolytes contain essentially no calories and generally do not break a fast. However, there are a few exceptions you should keep in mind.

Gummy vitamins typically contain 5–6 grams of sugar and about 25 calories per serving, which means they will break your fast. Protein powders, which often have 100 or more calories, and some liquid supplements will also interrupt your fasting window. As a quick reference, gummy vitamins break a fast, while standard tablet multivitamins generally do not.

Question 3

Can I take vitamin D while intermittent fasting?

Accepted Answer

Vitamin D is fat-soluble and is best absorbed when taken with a food containing fat. If you take it during a strict fasting window without food, its overall absorption may be significantly reduced. Because of this, most people taking vitamin D choose to take it with their first meal of the eating window.

Taking it alongside healthy fats, such as avocados, nuts, or olive oil, helps your body process the nutrient more effectively. Waiting until your eating window ensures you get the most out of the supplement without causing any digestive discomfort on an empty stomach.

Question 4

What supplements to take while fasting?

Accepted Answer

Supplements that generally do not break a strict fast include electrolytes like sodium, potassium, and magnesium, as well as creatine, standard tablet multivitamins, water-soluble vitamins, and adaptogen supplements.

Most strict fasting protocols consider these options to be gentle on the fast, meaning you can confidently take them without interrupting your progress.

On the other hand, supplements that break a fast include protein powder, gummy vitamins, and amino acids like BCAAs. These items contain calories or sugars that will interrupt your fasting state. For a full summary of which options are suitable for your routine, please refer to the master table above.

Fasting