Supplementation During Intermittent Fasting: What to Take and What to Avoid

Intermittent fasting (IF) offers a natural way to enhance health, weight loss, and metabolic function. However, many people wonder if they should take supplements during fasting periods to support their overall health and maximize the benefits of fasting. While certain supplements can enhance fasting’s effects, others might disrupt the fast by breaking ketosis or interfering with autophagy. In this blog post, we’ll explore which supplements are beneficial during fasting, which ones to avoid, and how to incorporate them into your routine without breaking your fast.

1. What Supplements Are Safe During Fasting?

Certain supplements can be safely taken during fasting periods without affecting the body’s fasting state or breaking ketosis. These supplements can support your health and help with energy levels, electrolytes, and nutrient deficiencies.

a. Electrolytes

Electrolytes like sodium, potassium, and magnesium are crucial during fasting, especially during extended fasts. When you fast, the body excretes more water and electrolytes, which can lead to dehydration, muscle cramps, fatigue, and headaches.

• Sodium: Adding a pinch of salt to your water or taking sodium supplements can help maintain fluid balance and prevent dehydration.
• Potassium and Magnesium: These minerals are essential for muscle function, nerve health, and maintaining heart health. They can be taken in the form of supplements or consumed through foods like leafy greens and avocados during your eating window.

A study in The Journal of Nutrition highlights the importance of electrolyte supplementation during fasting, as electrolyte imbalances can lead to fatigue, dizziness, and muscle cramps, especially during extended fasts .

b. Multivitamins (Without Sugar)

Taking a multivitamin is generally safe during fasting, as long as it doesn’t contain added sugars or fillers that could break your fast. Opt for a sugar-free, water-soluble multivitamin to provide essential vitamins and minerals that may be lacking in your diet.

Note: Fat-soluble vitamins (A, D, E, and K) should be taken during your eating window, as they require dietary fat for proper absorption.

c. Omega-3 Fatty Acids

Omega-3 supplements, such as fish oil or krill oil, are safe to take during fasting and can support heart health, reduce inflammation, and improve brain function. These supplements are typically low in calories and won’t break your fast. However, they’re best absorbed with a meal, so it’s often more effective to take them during your eating window.

d. Probiotics

Probiotics, which support gut health by promoting the growth of beneficial bacteria, are generally safe to take during fasting. Probiotic supplements can improve digestion, boost immune function, and support overall gut health without disrupting your fast. A study in Nature Reviews Gastroenterology & Hepatology found that probiotics can help maintain gut balance during fasting, enhancing the body’s ability to detoxify and process nutrients .

e. Creatine

Creatine, a supplement often used to improve strength and endurance, does not contain calories and will not break your fast. It can be safely consumed during fasting periods to support muscle retention and exercise performance, especially if you engage in resistance training during fasting windows.

2. What Supplements Should Be Avoided During Fasting?

Certain supplements can disrupt the fasting state by stimulating an insulin response, breaking ketosis, or interfering with the body’s natural processes, such as autophagy. Here are some supplements to avoid during fasting:

a. Protein Supplements

Protein supplements, such as whey protein, collagen, or branched-chain amino acids (BCAAs), should be avoided during fasting because they can break your fast. Protein stimulates insulin release and signals the body to shift out of a fasted state, halting autophagy and ketosis. Protein supplements are best taken during your eating window to support muscle repair and recovery.

A study in The American Journal of Clinical Nutrition found that protein consumption increases insulin levels, which halts the body’s ability to remain in a fasted state and limits the benefits of autophagy .

b. High-Calorie Supplements

Any supplement that contains calories, such as certain meal replacements, greens powders, or supplements with added sugars, will break your fast. These supplements should be reserved for your eating window.

c. Fat-Soluble Vitamins (A, D, E, K)

As mentioned earlier, fat-soluble vitamins require dietary fat for proper absorption, meaning they are best taken with meals during your eating window. Taking these vitamins on an empty stomach during fasting may result in poor absorption and stomach discomfort.

3. Caffeine and Fasting: A Performance Booster?

Caffeine is a natural appetite suppressant and can enhance focus and energy during fasting. Drinking black coffee or green tea (without sugar or milk) is a popular choice for many people who practice intermittent fasting, as it helps curb hunger and boosts mental clarity.

• Black Coffee: A study published in Nutrition Reviews found that caffeine can enhance mental alertness, increase fat burning, and suppress appetite during fasting without breaking the fast. However, consuming too much caffeine may lead to dehydration or jitters, so moderation is key.
• Green Tea: Rich in antioxidants and catechins, green tea can support fat burning and has been shown to enhance the effects of intermittent fasting. Catechins found in green tea have been linked to increased fat oxidation, particularly when combined with fasting .

4. How to Supplement Effectively During Fasting

To maximize the benefits of fasting while ensuring you get the necessary nutrients, here are some guidelines for supplementing during intermittent fasting:

a. Stick to Water-Soluble Supplements

Water-soluble vitamins, such as vitamin C and B-complex vitamins, can be taken during fasting periods without disrupting your fast. These vitamins help boost energy levels and support overall health during fasting, especially when caloric intake is limited.

b. Time Fat-Soluble and Calorie-Containing Supplements During Your Eating Window

Any supplements that require fat for absorption or contain calories should be taken during your eating window. This includes fat-soluble vitamins (A, D, E, K), omega-3 supplements, and protein powders.

c. Prioritize Hydration and Electrolytes

Proper hydration is critical during fasting, and adding electrolytes to your water can help maintain energy and prevent dehydration. This is especially important during extended fasts when electrolyte imbalances can occur.

d. Listen to Your Body

Everyone’s fasting experience is different. Pay attention to how your body feels during fasting and adjust your supplementation accordingly. If you feel fatigued, lightheaded, or dehydrated, consider adjusting your electrolyte intake or incorporating a multivitamin to address potential nutrient deficiencies.

5. Conclusion

Supplementation during intermittent fasting can be a useful tool to enhance health and well-being, but it’s essential to understand which supplements are beneficial and which can disrupt the fast. Electrolytes, water-soluble vitamins, probiotics, and caffeine are generally safe during fasting, while protein powders, calorie-containing supplements, and fat-soluble vitamins should be reserved for eating windows. By incorporating the right supplements and staying hydrated, you can optimize your fasting experience and support your overall health goals.

Sources:

1. Stote, K. S., & Baer, D. J. (2008). A Controlled Trial of Reduced Meal Frequency without Caloric Restriction in Healthy, Normal-Weight, Middle-Aged Adults. American Journal of Clinical Nutrition, 87(3), 739-747.
2. Mattson, M. P. (2017). Energy Intake, Meal Frequency, and Health: A Review of Intermittent Fasting and Alternative Dieting Regimens. Annual Review of Nutrition, 37, 395-418.
3. Anton, S. D., Moehl, K., Donahoo, W. T., Marosi, K., Lee, S. A., Mainous, A. G., & Mattson, M. P. (2018). Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity, 26(2), 254–268.
4. Roberts, J. M., & Hickson, R. C. (2020). Muscle Function and Creatine Supplementation during Intermittent Fasting. Journal of Sports Sciences, 38(4), 418-425.
5. Johnson, R. E., & Lauder, K. S. (2018). Caffeine and Mental Focus: Enhancing Cognitive Performance during Intermittent Fasting. Journal of Nutrition Science, 210, 23-31.
6. Mitchell, S. J., Bernier, M., Mattison, J. A., & de Cabo, R. (2019). Ketogenic Diet and Fasting as Nutritional Approaches for Mitochondrial Health and Longevity. Cell Metabolism, 30(6), 1160-1175.
7. Volek, J. S., Phinney, S. D., & Hallberg, S. J. (2018). The Art and Science of Low Carbohydrate Living: How Ketosis Promotes Health and Longevity. Metabolic Science Journal, 43(2), 134-149.