The ketogenic, or keto, diet has gained popularity as an effective method for weight loss and overall health improvement. This low-carb, high-fat diet shifts the body's primary fuel source from glucose to fat, leading to a metabolic state called ketosis. While many experience positive results, some encounter fatigue and other unpleasant side effects, often referred to as the "keto flu." This article explores the causes of keto diet fatigue and provides strategies to mitigate these symptoms.
Understanding Ketosis and the Keto Diet
The keto diet involves drastically reducing carbohydrate intake, typically to less than 50 grams per day. This restriction forces the body to burn fat for fuel, producing ketones as a byproduct. Ketones then serve as an alternative fuel source, and this metabolic state is called ketosis. When your body burns fat instead of glucose, this leads to elevated ketone levels, which is called ketosis. Symptoms can include changes in the way your breath smells, appetite, and energy levels.
The general breakdown of calories per day on a ketogenic diet is as follows: 70-80% of calories from fat, 5-10% of calories from carbohydrates and 10-20% of calories from protein.
During ketosis, the body undergoes several biological adaptations, including reduced insulin levels and increased fat breakdown. The keto diet excludes carb-rich foods like grains, beans, fruits and starchy vegetables.
Common Signs and Symptoms of Ketosis
It can be hard to know whether you’re in ketosis or not. Here are some common signs and symptoms of ketosis, both positive and negative:
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- Bad breath: Elevated ketone levels cause bad breath. Acetone, a ketone that exits the body in your urine and breath, is the specific culprit.
- Weight loss: Keto diets, along with other low-carb diets, are highly effective for weight loss. Fast weight loss can occur during the first week, primarily water weight. After the initial rapid drop in water weight, you should continue to lose body fat consistently as long as you stick to the diet and remain in a calorie deficit.
- Increased ketones in the blood: As you progress into a keto diet, you’ll start to burn fat and ketones as your main fuel sources. The most reliable and accurate method of measuring ketosis is to measure your blood ketone levels using a specialized meter.
- Increased ketones in the breath: A breath analyzer monitors acetone, one of the three main ketones in your blood during ketosis.
- Appetite suppression: Many people report decreased hunger while following a keto diet. The ketones themselves may also affect your brain, helping to reduce appetite.
- Increased focus and energy: Long-term keto dieters often report increased focus and energy. Eliminating carbs can also help control and stabilize blood sugar levels. This may further increase focus and improve brain function.
- Short-term fatigue: The initial switch to a keto diet can cause weakness and fatigue. These often cause people to quit the diet before they get into full ketosis and reap many of the long-term benefits. Electrolytes are often lost because of the rapid reduction in your body’s water content. When adding these supplements, make sure to include sodium, potassium, and magnesium.
- Short-term decreases in performance: Removing carbs can lead to general tiredness at first. This includes an initial decrease in exercise performance. After several weeks, many keto dieters report that their performance returns to normal.
- Digestive issues: Digestive issues such as constipation and diarrhea are common side effects in the beginning. Also, make sure to eat plenty of healthy low carb veggies, which still contain plenty of fiber.
- Insomnia: A lot of people report insomnia or waking up at night when they first reduce their carbs drastically. However, this usually improves in a matter of weeks.
Causes of Fatigue on the Keto Diet
Several factors can contribute to fatigue when following a keto diet:
Keto Adaptation
When first starting keto, your metabolism has to switch from burning carbs for fuel to burning fat for fuel. During this adjustment period (called keto adaptation), you may experience fatigue, headaches, and other minor side effects.
Electrolyte Imbalance
When you’re on a keto or low carb diet, your insulin levels stay very low and stable. In other words, on a low carb diet, your body excretes a lot more water and electrolytes. Dehydration leads to fatigue, brain fog, muscle cramps, and other issues.
Insufficient Calorie Intake
Ketosis suppresses appetite, making it easier to stay in a calorie deficit throughout the day. However, it’s also easy to undereat on keto because your appetite is suppressed.
Inadequate Fat Consumption
Guess what happens when you’re afraid of eating healthy fats on the ketogenic diet, where fat is your primary source of energy?
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"Dirty Keto"
Keto dieters can fall victim to “dirty keto” - a version of the keto diet that allows for highly processed and packaged foods. Although dirty keto follows the same breakdown of fats, protein and carbs as regular keto, it matters where your macronutrients come from. Filling your diet with caloric foods that have no nutritional value will leave you feeling run down.
Strategies to Combat Keto Diet Fatigue
Fortunately, several strategies can help alleviate fatigue and ease the transition into ketosis:
Stay Hydrated
A keto diet can cause you to rapidly shed water stores, increasing the risk of dehydration. This is because glycogen, the stored form of carbohydrates, binds to water in the body. When dietary carbohydrates are reduced, glycogen levels plummet, and water is excreted from the body. Staying hydrated can help with symptoms like fatigue and muscle cramping. Replacing fluids is especially important when you are experiencing keto-flu-associated diarrhea, which can cause additional fluid loss.
Replace Electrolytes
When following a ketogenic diet, levels of insulin, an important hormone that helps the body absorb glucose from the bloodstream, decrease. When insulin levels decrease, the kidneys release excess sodium from the body. Furthermore, the keto diet restricts many foods that are high in potassium, including fruits, beans, and starchy vegetables. Salting food to taste and including potassium-rich, keto-friendly foods like green leafy vegetables and avocados is an excellent way to ensure a healthy balance of electrolytes.
Ensure Adequate Calorie and Fat Intake
Try eating at least 3 meals a day at first, spread evenly throughout the day. And if you implement keto fasting, make sure to do it in a structured, intentional way. Eating enough fat, the primary fuel source on the ketogenic diet, will help reduce cravings and keep you feeling satisfied.
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Prioritize Nutrient-Dense Foods
To better avoid the keto flu and keep your energy up while on the keto diet, make sure your diet is filled with healthy protein and fat sources.
Get Adequate Sleep
Fatigue and irritability are common complaints of people who are adapting to a ketogenic diet. If you are having a difficult time falling or staying asleep, try one of the following tips:
- Reduce caffeine intake: Caffeine is a stimulant that may negatively impact sleep.
- Cut out ambient light: Shut off cell phones, computers, and televisions in the bedroom to create a dark environment and promote restful sleep.
- Take a bath: Adding Epsom salt or lavender essential oil to your bath is a relaxing way to wind down and get ready for sleep.
- Get up early: Waking at the same time every day and avoiding oversleeping may help normalize your sleep patterns and improve sleep quality over time.
Avoid Strenuous Exercise
While exercise is important for staying healthy, strenuous exercise should be avoided when experiencing keto-flu symptoms. Activities like intense biking, running, weightlifting, and strenuous workouts may have to be put on the back burner while your system adapts to new fuel sources.
Transitioning Off the Keto Diet
After months of eating high fat, high protein and very little carbs, how do you reset your body to eat normally again?
If you don’t transition properly off the ketogenic diet, you could be setting yourself up for some not-so-pretty symptoms:
- Weight gain.
- Bloating and other bathroom issues.
- Blood sugar spikes, which could cause fatigue and irritability.
- Increased hunger and sugar addiction.
Follow these tips on how to effectively come off the keto diet:
Focus on Hard to Digest Carbs
When looking to incorporate carbs back into your diet after severe restriction, focusing on eating carbs that are high in protein and fiber is recommended. Bean based pasta, crackers with seeds or sprouted breads are all great options when looking to bring carbs back into your diet.
Be Aware of the Sugar Pitfall
Don’t trade keto fat bombs for sugar bombs! One of the benefits of the ketogenic diet is the low sugar intake and eliminating added sugar in your diet. A good rule of thumb is to avoid anything with more than 4 grams of added sugar.
Maintain Good Habits
Weight loss isn’t just about the food - your environment, support system and lifestyle all play a factor in it. Staying hydrated is another important factor when working on healthy habits post keto.
Who Should Avoid the Keto Diet?
The keto diet should be avoided if you have certain medical conditions, including pancreatitis, liver failure, fat metabolism disorders and others. The keto diet may not be appropriate for pregnant or nursing people, children, and teens unless it’s being used therapeutically under medical supervision. Also, those with diabetes, kidney disease, liver disease, or pancreatic conditions who are interested in following a ketogenic meal plan should consult their doctor to determine if this diet is safe and suitable for their specific needs. Lastly, this diet may not be appropriate for individuals who are hypersensitive to dietary cholesterol.