How to avoid the Keto Flu on a Low-Carb Diet

How to avoid the Keto Flu on a Low-Carb Diet

Updated: Mar 26, 2024Veronika Larisova

Since their popularity surged in 1860 and again in 1972, low-carb diets have been a common health and weight loss strategy. These diets vary in carbohydrate restriction but lack a universal definition. They're categorised based on the percentage of daily caloric intake from carbohydrates or total daily grams:

  • Very low-carb: <10% or 20-50g/day
  • Low-carb: <26% or under 130g/day
  • Moderate-carb: 26%-44%
  • High-carb: 45% or more.


The ketogenic diet, the most famous very low-carb diet, also has restrictions regarding fats and protein. This diet is very high in fat and low in protein. The traditional ketogenic diet consists of 75-80% calories from fats, 15-20% from protein and 5-10% from carbohydrates. This strict ratio helps maintain ketosis, where the body efficiently burns fat for energy.

On the other hand, a low-carb diet restricts carbohydrate intake and doesn’t have to be high in fat. You can make up for the calories by eating more protein, which can be converted to glucose by gluconeogenesis if necessary.

One of the most common unpleasant issues when transitioning to a low-carb or ketogenic diet is the so-called keto-flu. The symptoms include constipation, headaches, fatigue, weakness and muscle cramps.

No matter what kind of low-carbohydrate diet you choose to adopt, these are our top three strategies you can implement to prevent or minimise the keto-flu and make the transition as smooth as possible:


1. Eat More Salt

When transitioning to a low-carb or ketogenic diet, your body undergoes significant changes that can affect its electrolyte balance, particularly with sodium levels. The process of ketosis and the reduction in insulin levels lead to increased excretion of sodium by the kidneys. This can result in a need for increased sodium intake to maintain electrolyte balance and prevent flu-like symptoms such as light-headedness, fatigue, weakness, muscle cramps and headaches.

Experts suggest that individuals on a low-carb diet may feel best consuming between 3–7 grams of sodium per day (which translates to about 7–17 grams of salt, or approximately 1-3 teaspoons of salt per day). However, these recommendations can vary based on individual health conditions, such as hypertension, kidney disease, or congestive heart failure, where one might need to be more cautious with sodium intake​​.

Adding salt to your diet is a straightforward way to ensure you're meeting your sodium needs. Obtaining sodium from bone broth, foods, or electrolyte supplements can be an effective alternative for those who prefer not to increase their salt intake directly. It's also important to note that during periods of heavy exercise or exposure to hot environments, the body's sodium requirements may increase further, making it necessary to adjust your intake accordingly​​. We recommend our beef bars and biltong for appropriately salty, low-carb snacks and meals on the go.


2. Hydrate Adequately

A very low-carb diet increases urine output and hydration requirements primarily because it reduces insulin levels, which in turn decreases sodium reabsorption by the kidneys, leading to increased sodium (and water) loss. Additionally, stored carbohydrates (glycogen) in the body are bound to water; as these stores are depleted on a low-carb diet, the water is excreted. This diuretic effect necessitates increased fluid intake to prevent dehydration. Drinking sugar-free natural electrolytes and adding pink salt to your drinking water are simple strategies to fix this issue.


3. Eat More Fats

Incorporating healthy fats like medium-chain triglycerides (MCTs) into your diet can enhance keto-adaptation, making the transition smoother and potentially easing keto-flu symptoms. MCT oil is particularly effective because it's rapidly converted into ketones by the liver, offering a direct energy source to your body. This swift conversion helps maintain the metabolic state of ketosis, optimising fat-burning and energy levels. Our collagen bars contain good fats from nuts and MCT oil. They are the perfect keto snack.


4. Take It Easy

Getting adequate sleep, refraining from high-intensity training, meditating, and adjusting your carbohydrate intake also helps. 


Read The Carbohydrate Appropriate Diet by our friend Cliff Harvey for the best guide to low-carb dieting.


Veronika Larisova
Co-Founder, Registered Nutritionist, Exercise Physiologist

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