You've cut the carbs, you're feeling motivated, and then a few days in, something feels off. A dull headache, a heavy tiredness, a bit of fog where your usual sharpness used to be.

If that sounds familiar, you've probably met the "keto flu". It sounds dramatic, but it's usually short-lived, and there's plenty you can do to make the transition smoother.

What Is the "Keto Flu"?

The keto flu isn't a real flu, and it isn't caused by a virus. It's a nickname for the collection of temporary symptoms some people notice when they first cut back on carbohydrates. These can include:

• Headaches
• Fatigue or low energy
• Irritability
• Brain fog
• Dizziness
• Muscle cramps
• Nausea or an unsettled stomach

Not everyone experiences it, and for those who do, it tends to ease within a few days to a couple of weeks as the body adjusts.

Why Does It Happen?

There are two main reasons.

1. Your Body Is Switching Fuel

Carbohydrates are usually the body's go-to energy source. When you reduce them, your body has to learn to rely more on fat, and that adjustment period can leave you feeling a little sluggish.

2. You're Losing Water and Salts

Lower carbohydrate intake means lower insulin levels, which prompts the kidneys to release more sodium and water. Along with them, you can lose other electrolytes such as potassium and magnesium. When these dip, headaches, cramps and tiredness can follow.

Gentle Ways to Ease the Transition

1. Drink Enough Water

Because you're shedding more fluid, staying hydrated helps. Keep a bottle nearby and sip regularly through the day.

2. Don't Fear the Salt

Many people find that seasoning food a little more generously helps in the first few weeks. A quality mineral salt, such as our Finally. Ancient Spring Salt, adds flavour and sodium to meals in one go. If you have high blood pressure or a kidney condition, check with your GP before increasing your salt intake.

3. Eat Potassium-Rich Foods

Avocado, spinach, mushrooms and salmon are all naturally low in carbs and good sources of potassium.

4. Add Magnesium to Your Plate

Nuts, seeds, leafy greens and dark chocolate (with a high cocoa content) can help top up magnesium.

5. Eat Enough

It's tempting to cut calories at the same time as cutting carbs, but that can make you feel worse. Fill up on protein and healthy fats, and let your appetite guide you.

6. Go Easy on Yourself

Save the intense workouts for later. A gentle walk, good sleep and a bit of patience go a long way while your body adapts.

7. Ease In Gradually

If a sudden switch feels too harsh, reduce your carbs in stages over a week or two instead of all at once.

When to Speak to a Professional

The keto flu is generally mild and temporary, but it's important to listen to your body. Please speak to your GP or a registered dietitian if:

• Your symptoms are severe or don't improve after a couple of weeks
• You take medication for blood pressure or diabetes, as these may need adjusting when your diet changes
• You have a health condition, are pregnant or are breastfeeding

A low-carb diet isn't right for everyone, so it's always worth getting personalised advice before you begin.

A Smoother Start

A little preparation makes the first fortnight far more comfortable. Stay hydrated, get your minerals in, eat well and be patient with yourself. Before long, the fog usually lifts, and you can focus on the good stuff.

Want support building a plan that suits you? Book a consultation with our nutritionist, or explore our low-carb pantry essentials.