Intermittent Fasting and Supplements: What You Need to Know

Practicing intermittent fasting (IF) is currently taking the health and fitness industry by blast.  From weight loss and improved insulin sensitivity to mental clarity and digestive health, the benefits are compelling.

But as more people combine IF with workout regimens, the question arises: Do you need supplements while intermittent fasting? If yes, which ones are safe and effective?

In this guide, we break down everything you need to know about using supplements during IF to help you reach your fitness and wellness goals without breaking your fast.

1. What Is Intermittent Fasting?

• Intermittent fasting is a diet in which you fast and then eat. Popular IF procedures are:

• 16/8 Strategy: Fast for 16 hours and eat within an 8-hour period.

• 5:2 Diet: Consume food routinely for five days and consume fewer calories for two days.

• OMAD (One Meal a Day): 23 hours fasting, 1 hour eating

IF regulates insulin levels, increases fat loss, and may improve the metabolic system.

2. Do Supplements Break a Fast?

It depends.

A supplement breaks a fast if it contains:

• Calories

• Sugar

• Protein or BCAAs (amino acids that trigger insulin response)

Generally, non-caloric supplements like electrolytes, multivitamins, and creatine don’t break a fast. But timing matters.

3. Best Supplements to Take During the Fasting Window

These can support hydration, energy, and mental clarity without affecting your fast:

• Electrolytes (Sodium, Potassium, Magnesium): Prevent cramps and fatigue

• Creatine Monohydrate: Non-caloric, supports strength & muscle retention

• Caffeine (Black Coffee/Green Tea): Boosts energy and focus

• Apple Cider Vinegar (in water): Supports digestion and appetite control

• L-Carnitine: Helps in fat metabolism

Pro Tip: Look for unflavored, sugar-free versions to avoid insulin spikes.

4. Best Supplements to Take During the Eating Window

Once your eating window begins, your body is ready to absorb nutrients. 

Prioritize:

• Whey or Plant Protein: Helps build muscle and aids recovery

• BCAA or EAA: Great post-workout if you train late in the day

• Omega-3 (Fish Oil): Anti-inflammatory and supports brain health

• Multivitamins: Covers nutritional gaps

• Probiotics: Supports gut health

For those with a performance goal, Bolt Nutrition's Whey Protein, BCAA, and Creatine are ideal additions to your routine.

5. Supplements That May Break a Fast

Avoid these during your fasting window:

• Protein shakes (including collagen)

• BCAA/EAA (they contain calories and insulin-triggering amino acids)

• Gummy vitamins or flavored tablets

6. Should You Supplement at All While Fasting?

Yes — especially if you're training hard or fasting for longer periods. Supplements help:

• Maintain energy and endurance

• Retain lean muscle mass

• Maintain nutrient intake even with a shortened eating window.

But keep it clean, minimal, and purpose-driven.

Conclusion

Intermittent fasting can be a powerful tool for weight loss and health, but supplements can enhance its benefits when used smartly. Whether you're training fasted, trying to maintain muscle, or just improving your health, knowing what to take and when is key.

Choose quality, avoid sugar, and listen to your body.