The road to ketosis isn’t without its speed bumps—namely: tiredness, stomach pains, and dizziness (just to name a few). These are just some of the common symptoms of the so-called keto flu, which is often experienced by those in the first week or so of the keto diet.

Truth be told, the term “keto flu” is a bit of a misnomer because it’s not really flu or even really contagious. It’s essentially a catch-all term for the body’s response to the carbohydrate restriction required by the keto diet. Nevertheless, it’s still an inconvenience for those who experience it. Below, we breakdown everything you should know about the keto flu, from why it happens and how you can avoid it from happening to you. Just scroll!


The body is primarily used to processing carbs for energy. When the body runs out of carbs to burn, as it does on the keto diet, it is forced to find another source of fuel. This transitioning of the body to a non-carb energy source is when ketosis occurs.

Ketosis, the goal of the keto diet, is when the body starts burning fat instead of glucose. The burning of fat, specifically fatty acids called ketones, over glucose as an energy source is met with some resistance from the body. Not for anything else, just by virtue of it being a change in the regular routine—growing pains, if you will.

During this period of adjustment, the body reacts the same way we do to any sort of shake-up to whatever we’ve grown accustomed to: the body bristles at the idea and feels uncomfortable at first, resistant to change as we are. It’s this temporary transitioning, this gaining of proverbial sea legs, that causes the symptoms collectively known as the keto flu.


The symptoms of the keto flu are called as such because they’re pretty much the same as a regular flu. The body fights change like it does a virus, but unlike an actual sickness, ketosis actually benefits you in the long run. As your body transitions into ketosis, you will experience flu-like symptoms of:

  • Weakness or general fatigue
  • Headaches
  • Nausea
  • Diarrhea or constipation
  • Muscle cramps and soreness
  • Mood swings
  • Difficulties in concentration
  • Sleep difficulties
  • Sugar cravings
  • Bad breath

Phew! Thankfully, the keto flu is a short-term state, typically only lasting for a week or so in most people, so weather through this storm of symptoms until your body achieves ketosis.

However, if you are experiencing prolonged diarrhea lasting more than a week, bouts of vomiting, or fever, stop your keto diet and see a doctor to reconsider your eating plans and nutritional needs.


The keto flu affects people differently. Some people only have it for a few days, others experience it for a little over a week. The symptoms can be severe in some but non-existent in others. This is because of a phenomenon called metabolic flexibility.

This basically describes the adaptive capacity of an organism to adapt fuel oxidation to fuel availability. In simpler terms, this is basically how well your body can adapt to using different fuel sources like carbs, glucose, fats, proteins, and ketones. Some people have bodies capable of effectively processing only one source, while others are metabolic gymnasts with their ability to burn through whatever is available.

A person’s metabolic flexibility is essentially a result of genetics and lifestyle. Some people may have genetic variations, such as a lack of certain enzymes that make it more difficult for them to adapt to change on the fly. Others may have genes that make their cells more easily adaptable to change. Lifestyle also plays a factor in a person’s flexibility. Someone with a high-carb diet of processed foods and sugary treats will probably have more difficulty battling the keto flu than someone who is an already clean eater by nature.

This same principle of metabolic flexibility can also be seen when applied to exercise. An hour-long, for example, can feel like a warm-up to an already active person, while a total wipe-out of a work-out for someone coming from a more-or-less sedentary state.


Taking care of your body during this period of transition is very important because it’ll help you develop your self-discipline and self-awareness. Any diet or fitness regimen is a mind over matter situation, so buck up and take the necessary steps to actively care for yourself. Here are some things you can do to manage the symptoms of keto flu.

1. Drink a lot of water with some unrefined salt. You can get dehydrated very easily on keto, especially within the first few days when your body is shedding a lot of water weight. To make up for this, women need to drink at least 2.7 liters of water while men need to drink at least 3.7 liters of water. To keep your electrolyte levels up, add some natural, unrefined salt to your water.

Unrefined salt aids in the sodium your body loses as a result in the decrease of insulin. Style icon Lauren Conrad swears by Himalayan pink salt for this purpose. Himalayan pink salt has 84 trace minerals, which can help you during the keto flu by detoxifying your body, nourishing your different systems, and boosting your energy levels.
TRY: Zin Himalayan Pink Salt, P204, The Green Tummy Himalayan Salt (500g), P220, Manila Superfoods Himalayan Salt Medium Coarse (500g), P245

2. Make up for the lost potassium. Along with the loss of sodium that comes with the decrease in insulin, you’ll also be losing potassium during this period of transition. Make up for this by adding more potassium sources like avocados and leafy greens into your diet. To make sure you’re meeting your body’s potassium needs, you can also use potassium supplements.
TRY: Herbs of the Earth Potassium Gluconate+, P890

3. Increase your magnesium intake. You won’t be losing magnesium during this period of carb restriction, but magnesium will help your body transition into ketosis more easily by making your body more sensitive to insulin. Magnesium will also help you manage some of your keto flu symptoms by treating or preventing muscle cramps and improving your sleep. Some keto-friendly sources of magnesium are almonds and pumpkin seeds, though magnesium supplements are highly suggested as well.
TRY: Herbs of the Earth Pure Magnesium, P1,099

4. Eat more fats, especially MCTs. To help your body achieve ketosis more quickly, give it more fat to burn. Fat provides the liver cells with the acetyl-CoA needed to make ketones. You can make do with just eating more foods with fat, sure, but the problem with this is that it is processed much too slowly. Animal fats from meat and dairy travel around the body, through the lymphatic system, your heart, muscles, and fat cells, before reaching your liver, and won’t be a readily available source of fuel for you.

To remedy this, supplement your diet with MCT oil. MCT oil is made of medium chain triglycerides, a type of saturated fat that can go straight to the liver after digestion. The liver can thus more quickly convert these into ketones and send them off to the cells that need them. This will help your body adapt to the keto diet, achieving ketosis more quickly while speeding through the keto flu symptoms or even avoiding it entirely.
TRY: SOZO Natural MCT Oil (250ml), P880, SOZO Natural MCT Oil Powder (250g), P1,780

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