Isn't Fasting Supposed to Give You Energy?

author avatar Dr. Eric Berg 06/12/2024

While people embark on fasts for many different reasons, many choose to do them for more energy. It can be shocking to feel depleted instead of rejuvenated after fasting.

Learn about fasting, how it affects your body, and how it can help your energy levels.

Transitioning to Fat Burning Mode

Switching your body's primary energy from glucose to fat takes time and patience. When you cut the carbs, your body begins focusing on fatty acids and ketones for energy.

Understanding Your Body's Energy Shift

Your liver starts breaking down fats into ketones when glycogen stores run low. Initially, this can lead to fatigue because, let’s face it, change is hard, especially for your cells that have been used to sugar.

This transition usually takes three to seven days, during which your body becomes more efficient at burning fat for fuel.

Timeline for Ketosis Adaptation

The journey into full-fat-burning mode varies but typically spans several days up to a week. It's not instant gratification, you’ve got to give it time.

You’ll start noticing fewer cravings and more steady energy levels once adaptation kicks in fully.

Carbohydrate Intake and Its Impact on Fatigue

Fatigue can hit you hard when you slash carbs to shift your body into ketosis. It's not just about cutting back; it's about finding the sweet spot that lets your body know it's time to burn fat for fuel.

Keeping carbs under 40 grams daily is vital, but tightening up to below 20 grams could be a game-changer if insulin resistance has been an issue for you.

Setting the Right Carb Limit

Carb restriction is difficult at first. When first cutting carbs out, do it slowly to ease your transition into a healthier lifestyle.

Listen to your body during this period, and consult a healthcare provider before undergoing any dietary changes or prolonged fasts.

The Role of Fasting in Accelerating Ketosis

When you skip meals, your body turns into a fat-melting machine.

Why? Because fasting cuts off the carbs, pushing you straight into ketosis, where your body burns fat instead of sugar.

Combining Fasting with Keto for Optimal Results

You're on a low-carb diet, but progress feels slow. Thankfully, studies show fasting can speed up ketosis significantly, especially when paired with carb-cutting efforts.

Gradually reducing eating windows lets your body adjust to fasts.

Dietary Adjustments to Combat Keto-Induced Fatigue

When your body screams for a carb fix, it's tempting to reach for keto snacks or bombs. Think again. These treats might seem like allies in your low-carb quest, but they could be disguised traitors.

The key here isn't avoiding all keto bombs, but to be discerning: pick foods that fuel this transition without putting on the brakes. Remember, every bite counts when training your body to switch energy sources.

MCT Oil and Exogenous Ketones as Energy Boosters

Now, let’s talk quick fixes—not candy bars but MCT oil and exogenous ketones.

When fatigue hits like a truck, these supplements can provide an immediate supply of ketones, helping power up your energy production pronto while aiding adaptation efforts during those early keto days.

Importance of Nutritional Co-factors in Keto Diets

You're on a keto diet, slashing carbs and ramping up fats. But without the right vitamins and minerals, you might as well be driving with flat tires. Your body needs nutritional co-factors like B vitamins (B5, B6, B1) to shift into high gear and burn fat efficiently.

Buckle up because these micronutrients are essential for converting those ketones and fatty acids into pure energy. Studies show deficiencies can leave you feeling drained.

Addressing Potential Nutrient Deficiencies

The signs of running low on these nutrients are not subtle; think fatigue or muscle cramps.

Start by tossing some nutritional yeast onto your meals and don't forget a mineral blend chock-full of potassium, sodium, and magnesium to keep the engine humming smoothly.

Supplements That Support Mitochondrial Function

If tweaking your diet doesn't do the trick to recharge your energy levels while adjusting to keto, think about adding supplements into the mix.

These can offer crucial mitochondrial co-factors that kickstart cellular activity, giving you the push you need when carbs aren't in your diet.

Practical Tips for Managing Fatigue During Fasting and Keto

In this exploration, we delve into practical tips for navigating and mitigating fatigue during fasting and keto, ensuring individuals can maximize the benefits of these lifestyle choices.

Discover strategies encompassing nutrition, hydration, and lifestyle adjustments to empower individuals to maintain energy levels and embrace the full potential of their fasting or keto endeavors.

Hydration and Electrolyte Balance

Feeling drained while you're fasting or on a keto diet? It might be because you are dehydrated. Hydration is crucial when it comes to kicking fatigue to the curb. But it's not just about chugging water—electrolytes are key players, too.

Sipping on an electrolyte-infused drink can help keep that energy level up. Without electrolytes, your body will struggle, leaving you feeling depleted.

Structuring Your Meal Plan Effectively

When crafting a meal plan, you need to pick the correct foods to help you throughout the day.

Eating nutrient-dense foods packed with fats and proteins will give you steady fuel without the sugar crashes. And remember, timing is everything—spacing out meals allows maximum absorption.

Coconut water

Harnessing the Benefits of Coconut Water

Explore a revitalizing solution for overcoming fasting slumps with the refreshing boost of coconut water. The benefits of coconut water, with its natural electrolytes and hydrating properties, make it a valuable ally in maintaining energy levels during fasting.

Discover the replenishing qualities of coconut water, offering both hydration and a flavorful alternative to support your fasting journey.

Incorporating the benefits of coconut water can be a refreshing and nourishing strategy to overcome slumps and enhance your overall fasting experience.


Fasting aims to boost energy, but it can initially leave you feeling drained. Transitioning from glucose to fat as your primary energy source takes about three to seven days. Initially, this can cause fatigue, but it ultimately leads to more stable energy levels.

Reducing carbs to below 40 grams daily helps enter ketosis, but it's essential to do this gradually to avoid fatigue. Combining fasting with a low-carb diet can accelerate ketosis.

To combat fatigue, choose nutrient-dense foods and avoid over-relying on keto snacks. MCT oil and exogenous ketones can provide immediate energy boosts.

Ensure adequate intake of B vitamins, potassium, sodium, and magnesium to support efficient fat burning and prevent fatigue. By understanding and managing these aspects, you can maximize the energy-boosting benefits of fasting.

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