Should You Supplement While Fasting?

It stands to reason that if you’re taking in fewer calories by fasting, you are also probably taking in fewer vitamins and nutrients. Whether or not that reduction is significant enough to affect your health depends upon how long you fast and whether you were deficient in any area before you started. Additionally, fasting folks often want to know whether supplements count as food in a fast. Most experts say they do not, but the timing of taking them is important.

First, consider that if you’re only consuming water and/or black coffee while fasting, quite a few vitamins can make you feel nauseated on an empty stomach, from B vitamins to zinc. If you are going to take any of these, you probably want to save them for your eating windows. (And if you’re not sure, definitely wait).

Vitamins break down into two essential categories:

Fat-solubleThese vitamins should be eaten with fat-containing food in order for your body to absorb them: vitamin A, vitamin D, vitamin E, and vitamin K. The body stores fat-soluble vitamins in the liver and body fat. Taking these in windows when you aren’t consuming food with fat in it means you’re less likely to absorb them, so there’s no real point. While fasting for less than 5 days, you’ll be burning your own body fat and getting those vitamins that way.

Water-solubleThese vitamins are not stored in your body but excreted during the day if you drink liquids. They include: B-complex vitamins, like B1, B2, B3, etc, folic acid, vitamin C and many others. You can take these on an empty stomach, but again, they might upset it. If you’re doing short term fasting, you aren’t likely to deplete enough of these to affect your health negatively. You only need to consider supplementing if you’re fasting for more than a week.

If you are not already taking vitamin supplements pre-fasting, and are eating a wide range of healthy foods during your eating windows, you probably don’t need to begin supplementing at all. Science has yet to find conclusive evidence that vitamins and supplements have a significant impact on health unless you are deficient in one to begin with. In fact, some can do harm (too much vitamin C can cause kidney stones; too much vitamin E can cause blood-clotting problems).

L-tyrosine: If you’re still interested in supplementing, you might try adding L-Tyrosine. Your brain turns tyrosine into three major neurotransmitters: dopamine, which is linked to our mood and reward centers; norepinephrine, which helps our bodies deal with stress and muscle recovery, and adrenaline, which we need to get motivated and to focus under pressure. L-tyrosine may help you feel stronger and mentally sharper while fasting. You can take this on an empty stomach.

Electrolytes: The supplements you’ll most likely need to replenish during a fast are not vitamins at all, but electrolytes, substances the body needs to regulate and maintain a number of key bodily functions, and which are depleted through physical activity and fasting. The following are key electrolytes you’ll want to stay on top of (but don’t take in excess). The top two to pay attention to are sodium and potassium.

· Sodium. If you want to avoid headaches and muscle spasms, check the recommended daily allowance for your weight and gender.

· Potassium. This keeps your heart functioning well and your energy high.

· Magnesium. Among many jobs, it helps regulate muscle and nerve function, and can aid in sleep.

· Zinc. You might take zinc to help with the common cold, but it’s best known for aiding in testosterone production and nerve function. Be sure to take this with food, however, as it can cause nausea otherwise.

· Calcium. Your bones and your muscles both rely upon calciumContrary to what the dairy industry might want you to think, you don’t absorb it best through eating cheese and milk.

Focus on replenishing your electrolytes and keep up any vitamins you already take if possible. The longer you fast, the more likely you are to need supplementation, but most importantly, pay attention to how you feel and make sure your doctor knows you’re fasting. When you do eat, be sure to eat a variety of foods, or adopt a diet such as the Mediterranean diet, (a lifestyle change, not a fad diet), which is associated with reduced risk factors in a number of health conditions.


Posted in Does It Break My Fast?


    • From what I’ve researched, if you keep total number of calories consumed during your fast to under 50, it’s not considered “breaking” it.

      • If you are doing clean fast for healing, yes you are breaking the fast. For clean fast just water, green tea, black coffee, no sugar substitute, no cream, no lemon!

      • Water only, no artificial sweeteners, no sweeteners! 50 calories or less a day is not still fasting, this is a misconception!

      • It doesn’t matter what people consider “breaking”

        it’s scientific – if what you ingests causing any increase in insulin (even the slightest ) your fast has broken. Mostly any caloric food/drink will do so other than black coffee or tea.

    • Stevia does initiate a glycemic response in the body so it depends on what you’re fasting for. Autophagy? No. Burning fat, probably no problem.

      • No lemon??? Darn I was doing lemon, cayenne pepper, and ginger when I wake up. I guess I have to wait tile 10 am to drink that now???

  • According to Dr. Berg, Stevia does not increase your insulin levels significantly, so that little bit, technically, would not break your fast.

    • Dr Berg also said that *any* insulin, no matter how small, in the body prevents HGH and goes into storage mode. One of the key points of fasting is to remove insulin from the body so HGH and body fat burning activates. So…. use Stevia if you want [shrug]

      • That usually means you are increasing the amount of calories you are eating. Some people feel ravenously hungry when starting out, and so they tend to overeat during their window. Remember that you still have to take into account your calorie intake if you want weight loss. The fasting helps kickstart your metabolism, but it doesn’t prevent you from gaining weight I’d you increase calories. Try tracking your caloric intake.

      • Calories have nothing to do with weight gain or fasting. If you are gaining weight during a fast that means your body is most likely burning fat and replacing the fat in the cells with water. Water weighs a lot. You should get a wish effect 1-2 days after you eat when your body lets that water go.

    • Dr Berg is also just a chiropractor that sells supplements, not a real doctor or a research scientist in the field and doesn’t know what he’s talking about any more than some random person doing keto / IF

      • Very true. When I saw the line of supplements he sold I lost a bit of respect for Dr Berg.

      • Stevia is an alternative to sugar because our bodies do not digest it. When your body does not digest something it doesn’t use those micronutrients as fuel or energy.

        Stevia may be used as alternative to sugar and in theory should not break your fast.

        Credit: Nurse

  • Does taking nitric oxide capsules break a fast? L-arginine is mainly the ingredient along with L-citrulline malate. Just wondering so that I could take it to boost blood flow and endurance while I’m fasted training?

    • The problem with magnesium supplements is many of them contain extra stuff that can activate your metabolism. If your main goal is fat loss, they won’t be a problem because they’re basically no calories.

      Honestly, no one knows forsure the effect a little binder and whatever else comes in a magnesium pill will have on autophagy because it hasn’t been specificly studied.

      I’d recommend just taking it during your feeding window. The only time I supplement with magnesium outside of a feeding window is when I’m doing a prolonged fast (3+ days).

    • It depends. What I think about is gum and breath mints do not curb your appetite they actually trigger hunger. Personally I am getting off artificial sweeteners.

    • Going by my own logic: if black coffee (which does have very little calories) doesn’t break a fast, biting of about 1/4th of a piece of gum to freshen the taste in my mouth isn’t going to break it either.

      • Not necessarily… it’s not always only calories to worry about. Just think about the ingredients and chemicals in the gum. Just putting a 1/2 pea sized food on your tongue due to artificial flavoring can and will activate your insulin response. My personal response would be yup it breaks your fast.

    • I use PUR brand gum. Is uses stevia or erythritol to sweeten. For me, I’ve never had a problem with my fasts going askew and they don’t trigger hunger.

    • I would only supplement ANYTHING during the feeding window. There is really no true reason for supplementation during your fast. If you are not an elite athlete you do not need supplementation for your fasted workout. Even absorption os supplements are usually better NOT on an empty stomach.

  • As a diabetic, I need to take insulin. No questions on that, it’s a must. But how does taking it affect my fast? And how much is too much? By the way I don’t plan on fasting for more than 24 hours at most. I usually do intermittent fasting every day.

  • Can I drink tamarind water during my fasting window, also can I take my pre workouts during my fasting window as I workout 🏋️‍♂️ during the fasting window

  • I’m currently about 45 days into an 18:6 fast intermittent fasting schedule, I want to start supplementing potassium. I’m confused though the tablets I have, 99 mg, only have 2% of the daily recommended value? What is a recommended amount to supplement potassium?

    • 4700mg but the best way to get most of potassium from food like spinach nuts and most of green leafy veg. 45 days try to get yours metabolism reset because after all these fasting your brains is mode of saving most of energy. To do this trying to get normal and carbs diets for week to get your body metabolism faster than get back to keto and fasting, That shock Your body to use more power from carbs and fats but You already have processes for better ketone production in the liver. Good luck

    • 4700mg is the RDA. You can buy NO Salt which gives you 1000mg for 1/4 tsp. Dr Berg has a supplement that you can mix in water gives 1000mg. Also there is supplement online called Keto 1000. Also coconut water as well as tomato juice is high in potassium. I keep them on hand for my eating windows

    • The research I’ve done on potassium showed that the industry regulates supplements to 99 mg to prevent overdose, but 99 mg is a ridiculously low amount. My dietary app daily value says 4700 mg is safe intake for me; you’ll have to take a lot of supplements to achieve that at 99 mg. Id recommend also finding rich dietary sources for the days you ate eating.

    • You should not drink Gatorade at all under any circumstances! It’s loaded with artificial garbage that will have a negative impact in many levels!

    • You can but it may interfere with the benefits, especially autophagy, so why but stick with water? Forgetting about fasting for a moment, why put that stuff in your body? My philosophy is to not drink anything that humans haven’t been drinking for thousands of years. Tea, water, wine are fine. But Tropicana, Monster Energy drinks, and anything produced by the Coca Cola bottling company are out. As far as I’m concerned the jury is out on the long term consequences of consisting these products. But from what evidence is emerging it’s not looking good.

      • So, the thing with Gatorade is that it has electrolytes, which are intensely important, even most during fasting. That’s the whole point of it. Most experts will say that any Gatorade will break a fast, whether it has calories or not. But if that’s what you like and it is a good way to make sure you’re getting electrolytes, don’t let anyone shame you out of it.
        People have had feinting and heart issues because they drank only water and exercised too much. Electrolytes are vital.

    • You can but it may interfere with the benefits, especially autophagy, so why but stick with water? Forgetting about fasting for a moment, why put that stuff in your body? My philosophy is to not drink anything that humans haven’t been drinking for thousands of years. Tea, water, wine are fine. But Tropicana, Monster Energy drinks, and anything produced by the Coca Cola bottling company are out. As far as I’m concerned the jury is out on the long term consequences of consisting these products. With the exception of the effects of caffeine, the ingredients in energy drinks have not been thoroughly studied to confirm the cardiovascular safety or the proclaimed energy-boosting benefits.

    • The calories in a no-carb, high-fat “keto” coffee WILL BREAK A FAST. I love mixing coffee with organic grass-fed butter and coconut oil, but I do so to break my fast when my eating period is in the late morning-early afternoon. It’s such a delicious and energizing way to break a fast. If you are in ketosis and choose to drink a “keto” coffee, you will not be kicked out of ketosis, but you will not get some of the greatest benefits of being in a completely fasted state (like autophagy).

  • Alex – Artificial sweetners such as those in sugar free drinks may cause an insulin spike.

    I avoid coke zero and pepsi max at all costs while fasting ..

  • Actually i have found my way of taking the above needed minerals except zinc by taking 12 tissue salt i bought at the homeopathy drug store which it has iron, potassium, sodium, silica, calcium and magnesium inside the tablet. It’s quite convenient and it doesn’t have any side effects too.

  • Hello, this is my second try in doing the intermittent fasting and it really works. I am doing the 16:8 because it worked for me. However, can I have no sugarless, no caffeine, hot chocolate?

  • If I drink a morning homemade lemon and ginger drink (water boiled with ginger and lemon) will it break my fast?

  • I take a probiotic 3x/day. Is that ok to take while fasting? Today will be my first day trying the 16:8 fast. Going to turn on the fasting timer at 8 pm this evening. Wish me luck.

  • Does anybody know if brewers yeast tablets will break a fast? The dosage is 6 pills a day at ten calories total, so about 1.6 calories per pill.

    • Hi Suzy,

      There is evidence online of the fact that Brewer’s yeast actually;

      • Enhances insulin sensitivity.
      • Lowers blood sugar levels.

      There are warning out there for diabetics and BY as along with their medication it can cause abnormally low blood sugar.

      It also comes with fibre that reduces the small amount of carb content also.

      If you check out the world record longest fast by the Scottish person done under medical supervision. You’ll find that “Angus” used a number of supplements and lots a monster amount of weight, as well as improving his health.

      Now, I believe that it was nutritional yeast he used. However, the previous information I shared was in BY.

      1.6g seems low. I’d investigate a high quality NO GMO version of the powder. You may find this more economical.

      Good luck

  • What about collagen in black coffee? Every morning I usually do 1 scoop of collagen in my
    Coffee is this slowed? There are
    No sweeteners and it’s unflavored

  • Does melatonin break a fast? I use it sometimes to help me sleep but don’t want to use it if it’ll break the fast process before I go to bed.

  • Does chewing tobacco break your fast?? I sometimes like to dip at night to help me relax.. will this cause my fasted state to end?

  • Can we take far burn during morning 1-2 hours before breaking intermittent fast. It contains thermogens, green tea , caffeine etc.

    • I would start off 3 days a week for a 16:8 fast. As you get use to it, increase your day by one; or switch it up from 18:6 fast 3 days a week.

  • I don’t prefer black coffee. Can I instead drink unsweetened black iced tea instead during the fasting period? Or does it need to be green tea?

  • If you are not eating enough during your eating window, it is possible that your hypothalmus has decided to reset your body’s allowed daily calorie intake to below what you are taking in which means you will gain weight. It does this as a survival mechanism.

  • Hello. I’m interested in trying Dr. Attia’s recommendation for Doc Parsley’s Sleep Remedy. How does this fit into ones fasting routine? For reference, I try to stop eating around 6:30pm and eat the next day with a 16/8 format. However, if I’d like to go to sleep around 1030pm and take this supplement at say 930pm, will it impact my fasting window? Thank you!

  • Can you do 16:8 everyday? Is it best to have rest days and if so how many calories or carbs should be consumed? I’m in need of losing 50 lbs and want to know what to do for best and fastest results.

  • I am on sleep medication and anti-depressants. Is it fine if I am fasting from evening through the night and still take these medicines?

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