How do you stop a headache on a low carb diet?

October 6, 2025 •

3 min read

Up to 25% of people report experiencing headaches during the initial phase of a low-carbohydrate or ketogenic diet. If you find yourself asking, 'How do you stop a headache on a low carb diet?', you're not alone. This phenomenon, often dubbed the 'keto flu,' is a temporary adjustment period as your body shifts from burning carbs for energy to burning fat. The good news is that with a few simple, targeted strategies, you can manage and prevent these painful side effects.

Quick Summary

Headaches experienced during a low-carb diet are typically a side effect of the body adapting to new fuel sources. Common causes include dehydration, electrolyte imbalances from increased urination, and temporary low blood sugar. Relieving these headaches involves boosting hydration, replenishing essential minerals like sodium, potassium, and magnesium, and ensuring consistent nutrient intake during the transition period.

Key Points

Stay Hydrated: Drink plenty of water to counteract the fluid loss that occurs when first restricting carbohydrates.
Replenish Electrolytes: Actively increase your intake of sodium, potassium, and magnesium through foods and supplements to prevent imbalances.
Eat Nutrient-Dense Foods: Focus on leafy greens, avocados, nuts, and seeds to naturally replenish lost minerals.
Manage the Transition: Avoid intense exercise and ease into your low-carb diet gradually to minimize stress on your body.
Address Underlying Issues: Headaches can also be exacerbated by stress and lack of sleep, so prioritize rest and relaxation.
Consider Supplements: Electrolyte supplements can be an effective and convenient way to ensure adequate mineral intake during the adjustment period.
Consult a Professional if Needed: If headaches are severe, persistent, or accompanied by other concerning symptoms, seek medical advice.

The Causes of Low Carb Headaches

Electrolyte Imbalance

The most significant contributor to low-carb headaches is an imbalance of electrolytes. When you drastically cut carbohydrates, your insulin levels drop, which signals your kidneys to release more sodium and water from your body. This loss of sodium, along with other key electrolytes like potassium and magnesium, can disrupt cellular functions and trigger headaches, fatigue, and muscle cramps.

Dehydration

As a direct result of electrolyte loss, your body expels more water, leading to dehydration. Dehydration can cause the brain to temporarily shrink, pulling it away from the skull and putting pressure on surrounding nerves, which causes headaches. Maintaining hydration is therefore critical, especially in the early stages of the diet.

Low Blood Sugar

During the initial transition, your body must adapt to using fat and ketones for fuel instead of its preferred source, glucose from carbs. This can cause a temporary dip in blood sugar levels (hypoglycemia) as the body learns to efficiently use ketones. This fluctuation in glucose can trigger headaches and feelings of lightheadedness or tiredness.

Immediate and Long-Term Headache Remedies

Hydration

Drink Plenty of Water: Aim for at least 68 ounces (2 liters) of water per day, increasing your intake if you are active or in a hot climate.
Add Salt: Liberally salt your food to replenish lost sodium. You can also add a pinch of salt to your water.
Choose Hydrating Foods: Incorporate water-rich, low-carb vegetables like cucumbers, zucchini, and lettuce into your meals.

Electrolyte Replenishment

Eat Nutrient-Dense Foods: Focus on foods naturally high in potassium and magnesium. Excellent options include avocados, spinach, kale, pumpkin seeds, and almonds.
Use Electrolyte Supplements: An electrolyte supplement, ideally without added sugar, can be a convenient way to ensure consistent intake of sodium, potassium, and magnesium.
Drink Bone Broth: Sipping on bone broth is an easy and delicious way to get sodium and other minerals.

Lifestyle Adjustments

Ease In: If you are very sensitive to rapid changes, consider reducing your carb intake gradually rather than all at once.
Eat Regularly: Avoid skipping meals, as this can exacerbate blood sugar drops.
Moderate Exercise: In the first week or two, avoid intense, strenuous workouts that can further deplete your glycogen stores. Opt for light activities like walking or yoga instead.
Prioritize Sleep: Fatigue and stress can worsen headaches. Ensure you get adequate sleep to help your body adapt.

Low Carb Headache vs. Migraine

Understanding the difference between a simple 'keto flu' headache and a more severe migraine is important. A typical keto headache is a temporary, dull throbbing pain, while a migraine is a complex neurological condition with more intense and specific symptoms.


Feature	Low Carb Headache ('Keto Flu' Headache)	Migraine
Onset	Occurs during the first few days to weeks of starting a low-carb diet.	Can be triggered by many factors, not just diet changes.
Pain Type	Typically described as a dull, throbbing ache.	Often causes a severe, throbbing or pulsing pain, usually on one side of the head.
Associated Symptoms	Fatigue, brain fog, irritability, muscle cramps, dizziness.	May include nausea, vomiting, and extreme sensitivity to light and sound.
Duration	Usually resolves within a week or two as the body adapts.	Can last for hours to several days and reoccur frequently.
Key Cause	Dehydration, electrolyte imbalance, low blood sugar from diet change.	Complex neurological disorder with varied triggers.

When to See a Doctor

While low-carb headaches are generally a temporary annoyance, you should consult a healthcare professional if:

Your headaches are unusually severe or debilitating.
They persist for more than a few weeks.
You experience other severe symptoms, such as muscle stiffness, rapid breathing, or unusual confusion.

Conclusion

Experiencing headaches on a low-carb diet is a common but temporary side effect as your body enters a new metabolic state. By proactively managing hydration, replenishing electrolytes, and making small lifestyle adjustments, you can effectively combat the 'keto flu' and continue your journey toward your health goals. Most people find that the discomfort subsides as their body fully adapts, leading to improved energy and clarity. For more information on the science behind low-carb diets, consider exploring resources from reputable institutions such as Harvard T.H. Chan School of Public Health.

Frequently Asked Questions

Headaches on a low carb diet are most often caused by dehydration and electrolyte imbalances, particularly sodium loss, as your body flushes out water when it first depletes its carbohydrate stores. Temporary low blood sugar as your body transitions to burning fat for fuel can also be a factor.

For most people, low carb headaches are part of the 'keto flu' and are temporary. Symptoms typically appear within the first few days and should subside within a week or two as your body fully adapts to the new metabolic state.

Yes, you can proactively prevent headaches by staying well-hydrated, adding extra salt to your meals, consuming electrolyte-rich foods, and ensuring you get adequate rest.

To help with headaches, focus on foods rich in water and electrolytes. Good options include avocados (potassium, magnesium), leafy greens like spinach and kale (magnesium, potassium), nuts and seeds (magnesium), and salting your food for sodium.

While not always necessary, an electrolyte supplement can be a very effective and convenient tool to ensure you are replenishing the sodium, potassium, and magnesium lost during the initial phase of a low-carb diet.

Yes, strenuous exercise can worsen low carb headaches, especially in the early stages when your body's glycogen stores are low. It's best to stick to moderate activity until your body has fully adapted.

You should see a doctor if your headache is debilitating, lasts longer than two weeks, or is accompanied by severe symptoms such as rapid breathing, muscle stiffness, or extreme confusion.