How to Avoid the Keto Flu

Mar 23, 2021

You did all your grocery shopping. You stocked up on fatty fish, bacon, berries, greens, nuts, and cheeses.

All your macro-counting apps are downloaded and ready to roll.

You have purchased portion-control Tupperware sets and prepped all your food for the week. You are so on top of it all. This is going to be AHHHMAZING!

Finally, your waistline will more closely resemble that of Mr. Clean than that of the Michelin Man. Here comes the six-pack of your dreams! Right? Well, almost.

How to Avoid the Keto Flu

It has been three days of your keto diet conquest, and suddenly it hits you. You feel like absolute you know what — that word that rhymes with “fit,” which is all you are desperately trying to be.

Your mind runs a bit wild. Could you be pregnant? (Well, no. That would require leaving your house and actually meeting someone. Thanks, Corona. We can cross that possibility off the list.)

With the rampant viral pandemic, could you have contracted COVID-19? What the heck is going on? Not to worry, it is most likely just the keto flu.

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When you take on the ketogenic diet, your body makes a significant change. It goes from metabolizing glucose for energy to using fat instead.

This happens when you eliminate carbohydrates from your diet and instead consume more protein and even more fat, which can trigger keto flu symptoms.

These symptoms can closely resemble those of the typical flu: nausea, vomiting, headaches, fatigue, and muscle aches. Fun, right?

The good news is that all these symptoms are caused by just a few key factors derived from the major change in your diet.

You may be wondering how long does the keto flu last? The best part is that it is only a few days to a week, at most.

Once you get past it, you will likely feel better than ever and will have seemingly endless amounts of energy. Truth be told, it can be pretty miserable, so let that be your incentive not to slip up and “cheat” on your new diet.

That will kick you back to square one, and you will have to suffer through the symptoms all over again. Keep reading to learn the six major causes and how to avoid the keto flu.


1. Carbohydrate Withdrawals

The first and most obvious cause of the nasty keto flu is carb withdrawals.

If you are used to eating bread, pasta, rice, and starches (all of which convert to glucose when digested), your body has become accustomed to foods that are metabolized quickly and therefore, an immediate (but short-lasting) source of energy.

With the keto diet, you will be sourcing most of your energy from fats and some proteins. These take much longer to digest but will also keep you feeling full for an extended period.

The solution for the carb withdrawal-induced flu is to simply eat more fats and proteins and wait it out.

Whatever you do, do not cave in and reach for that slice of pizza. In doing so, you are flipping the switch back to using glucose for energy and kicking your body out of ketosis.

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2. Go with Your Gut

Another cause of the uncomfortable symptoms you may be feeling is a change in your gut microbiome.

There are several ways to achieve ketosis. You can even do it if you are vegan or vegetarian. However, it is common, especially in the beginning, to binge on dairy and red meats or bacon.

While these items are well within the realm of what is allowed on the keto diet, consuming too much of those things is not healthy and may cause your stomach to churn.

Make sure that in addition to those items, you are also consuming lots of leafy greens. Add a strong probiotic supplement to your diet and consider taking a dietary fiber supplement as well.

Eat lots of yogurts (but read the nutrition label first) because it contains heaps of added sugars and is therefore loaded with carbohydrates.

It may be best to stick with plain Greek yogurt, and if you must sweeten it, add your own sugar-free sweetener (like stevia or Swerve.)

(Related: Plant-Based Keto: Not All Fats Are Created Equal)

3. Keep Your Electrolytes in Check

When your body is primarily using fat for energy, you are at risk of depleting your electrolytes faster than when not in ketosis.

When you exercise frequently, this risk becomes even greater. As you metabolize and flush fats out of your system, you are also losing a lot of sodium, which binds to the fat.

Electrolyte imbalances can cause muscle cramping, fatigue, dizziness, weakness, and nausea. Luckily, the solution is easy: consume more salts than you normally would.

You can add freshly squeezed lemon juice and sea salt to your water to make natural electrolytes (and a yummy, carb-free alternative to Gatorade).

How to Avoid the Keto Flu

4. Drink More Water Than You Think You Need

Because of the change in your diet, you are also at a higher risk for dehydration. Your system is busy flushing the fats out, which takes a higher level of water content.

If you aren’t careful, you can eliminate too much water, leaving you with all of the symptoms of dehydration, and thus the keto flu (headaches, diarrhea, and fatigue, just to name a few).

Again, the solution for this is very simple. Drink more water!

It is helpful to carry a water bottle with you throughout the day so that you don’t forget and so that you always have access to it.

We love Hydro Flasks because they are insulated, keeping your water at whatever temperature you pour it at for long periods of time. We know what you’re thinking: Who the heck would spend $40 on a water bottle?!

But the proof is in the pudding (or should we say, in the double-walled insulation?) You can literally leave one of these bad boys in a hot car for days on end and still come back to ice-cold water.

If you are into the Bulletproof coffee regime in the mornings, they are equally as great for keeping beverages hot.

Everything You Need to Know About Intermittent Fasting On Keto

5. Ease into the Keto Diet

Another reason why you may feel icky for the first few days of being in ketosis is because your body is in shock.

If cutting carbs is a drastic change for you, you will likely feel worse than if your carb intake was somewhat minimal before you started.

The solution for this is to take a more gradual approach by easing into ketosis.

If you have a macro tracker app, that may help. If the macro goal is 75% fat, 20% protein, and 5% carbohydrates, perhaps you can start with 50% fat, 25% protein, and 25% carbohydrates and work your way down for a week or two. This should help prevent shocking your system and experiencing the keto flu.

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How to Avoid the Keto Flu sleep more

6. Get More Sleep

When initially making such a drastic change in your diet, it is common that you will experience fatigue.

You may run low on energy for the first few days to a week while working through the keto flu. To help your system adapt, allow yourself some extra downtime. If you are an avid gym shark or athlete, perhaps plan to take 2–4 days off from training while you ease into ketosis.

It will make the transition a bit easier, and when you get through the keto flu period, you will feel incredible and unstoppable. It will all be worth it!

The keto diet is just one of those things that you cannot cheat on. Many fad diets suggest that a “cheat day” here and there is fine.

However, with keto, any overconsumption of carbohydrates can immediately kick you out of the ketogenic state, which means your body will switch back to metabolizing glucose for energy, instead of fat.

As soon as that switch is flipped, you may have to suffer through the keto flu again to switch it back.

The key is getting through it once and sticking to it. That doesn’t necessarily mean that you need to suffer or miss out on foods that taste good.

In fact, due to the ever-growing popularity of the keto diet, there are many delicious snacks on the market that won’t ruin your dieting efforts.

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