The combination of carb restriction and ketosis is what makes the keto diet so effective for so many. The decreased hunger and increase energy levels that most keto dieters experience make it so much easier to eat fewer calories, improve health, and lose weight naturally.
Unfortunately, to reap all of the benefits of keto dieting, you may have to experience some unpleasant symptoms as your body adapts to low-carb living. These symptoms typically include mild digestive issues, mental fogginess, decreased physical performance, and other flu-like symptoms.
Before you get discouraged and give up on your hopes of having your ideal body, check out our list of common keto conundrums and how to address them. You won’t necessarily suffer from them, but if you do, there are many strategies that you can use to remedy these issues.
1. Mental and Physical Fogginess
When you first start keto dieting, the first day will probably feel great, but eventually, about 2 to 3 days later, the mental and physical fogginess will hit. You may find yourself staring at the wall for extended periods of time, feeling half-drunk, and being unproductive at work.
The primary reason this occurs is because your brain is used to running primarily on glucose (and it can’t burn fat for fuel). During the first day of keto, you felt fine because you still had some glycogen (our storage form of sugar) left to burn — but, after around 24 hours, you burned it all off. As a result, your neurons will stop getting the energy that they are used to burning, and your cognitive function will start to decline.
The good news is that if you can push through it, the cloudiness generally clears after a couple of days, and you will experience an elevated sense of mental clarity after your brain starts burning more and more ketones for fuel (this may take around one to two weeks of keto dieting).
Tips for alleviating mental and physical fogginess during the first few days of keto:
- Go super low carb for the first week (no more than 10g of net carbs per day). By doing this, you will force your body to use up your glycogen stores and get into ketosis much more quickly.
- Start your diet off with an intermittent fast. Intermittent fasting is a great way to speed up your induction into ketosis. To learn more about intermittent fasting, check out.
- Use high-intensity exercise and low-intensity exercise strategically. First thing in the morning on your first day of keto dieting, do some high-intensity exercise. On the following days, do some light exercise, like walking or cycling, to start your morning. By using exercise in this way, you will burn through your glycogen stores much more quickly and encourage your body to burn more fat.
- Consume MCTs when you start to feel fatigued. MCTs are the only fats that will go directly to the liver from the digestive tract where they are converted into ketones. By supplementing with these fatty acids, you will provide your brain with more fuel, so it doesn’t struggle when your glucose levels are low.
- Eat more low carb vegetables. The iron, manganese, and potassium in green vegetables all play a crucial role in keeping your mind clear and energy levels consistent. To learn more about what veggies you should eat while you are on keto, check out our guide on low carb vegetables.
2. Decreased Strength and Endurance
As your brain is struggling to energize itself during the first few days of carb restriction, your muscles will end up getting caught in the same conundrum as well.
Although your muscles are able to run on fat (unlike the brain), they still won’t be adapted to using mostly fat and ketones for fuel yet. As a result, you may experience a loss of strength and endurance.
Some keto beginners will find that they can’t follow the same workouts as before. They feel so drained so soon into their workout that they just can’t make it through their regular routine. The good news is that this will typically pass within the next month as your body adapts to burning ketones and fat instead of using mostly sugar for fuel.
However, if you’re training primarily consists of high-intensity activities that last longer than ~30 seconds at a time (e.g., sprinting, playing competitive sports, and lifting weights in sets that have more than 6 reps), you may still struggle to keep your performance at the same level as before. This happens because your body can not burn fat and ketones to fuel activities at high-intensities.
It doesn’t matter how keto adapted you are — your muscles will always require faster burning fuel sources like creatine phosphate and carbohydrates for high-intensity exercises. For this reason, you may need to incorporate more carbs in your diet or change your training strategies until your body is fully keto adapted and is finally able to refill its glycogen stores effectively (this can take anywhere from 3 to 6 months).
To prevent any loss in strength and edurance, try these strategies:
- Change your training regime temporarily. Focus on exercises that are of low to moderate intensity and/or high intensity that last for around 15 seconds per effort. Every three to five weeks, test out your capacity for high-intensity workouts by doing your original training regime. If you are still struggling, then give your body more time to keto adapt. To learn more about the rationale behind changing your exercise routine. If you would rather not change your training regime for any reason, try implementing a targeted keto diet or cyclical keto diet instead.
- Implement a targeted ketogenic diet. You can do this by consuming a small amount of easily absorbable carbs before your workouts. To learn exactly how to follow the targeted ketogenic diet.
- Try using a cyclical ketogenic diet. This keto diet approach provides you with another way of upping your carb intake so that you can improve performance and reap the benefits of ketosis at the same time. To learn exactly how to follow the cyclical ketogenic diet, read through.
- Make sure you are meeting your macronutrient needs. Consuming enough protein and fat is a crucial component of your diet success and exercise performance. If you are not eating enough fat or protein, you will not be able to optimize your workouts. To find out how much you need to eat of each macronutrient while you are on keto, use our keto calculator.
- Eat plenty of low carb vegetables. The iron, manganese, and potassium in green vegetables are all important for keeping your energy levels consistent. To learn more about what veggies you should eat while you are on keto, check out our guide to low carb vegetables.
Keep in mind, however, that you may not need to use these strategies at all. Some keto dieters have no problem adapting to carb restriction and will have no issue when it comes to following their usual exercise routine.
3. Digestive Issues — Constipation and Diarrhea
Whether you are experiencing constipation or diarrhea, your symptoms can easily be remedied. Some people may tell you that eating so much meat will clog you up and that all of the fat you are eating will cause diarrhea, but this is not true.
Typically, if you experience diarrhea in the first week of keto, it is because your body is excreting excess water, and one route it uses to release that water is your digestive tract. Once your body adjusts to having lower insulin levels, your stools should start becoming more and more solid.
If your stools are still runny after you are in ketosis, you may not have enough fiber in your diet to give your bowel movements enough bulk. On top of that, you can also experience occasional bouts of constipation for the same reason.
Tips on how to remedy digestive issues on keto:
- Eat more low carb vegetables. The minerals and soluble fiber in these veggies will provide your stool with some bulk while simultaneously remineralizing your body. This will help you prevent constipation and diarrhea at the same time. To learn more about what veggies you should eat while you are on keto.
- Get hydrated. Consume plenty of water and minerals to bring balance back to your digestive tract. For more specific recommendations on how much water you should drink and what minerals you need to prevent issues, read through.
- Practice stress relieving methods. Stress can cause both diarrhea and constipation. Keto dieting will increase your stress levels at first, so make sure you are getting enough sleep every night and practicing stress relief methods like meditation, yoga, and outdoor walks.
The Primary Causes of These Keto Conundrums
After learning about all of these side effects, you may be wondering why the keto diet can be so difficult for us to adapt to at first. Although there are many reasons for these keto conundrums, the three main culprits are:
- mild dehydration
- hormonal shifts during keto adaptation
- not being in ketosis yet
Whenever we restrict carbs, our insulin levels decrease, which causes us to excrete a lot more water and sodium. This rapid water and sodium loss can eventually lead to dehydration and diarrhea.
If the body never gets rehydrated and remineralized, then cognitive function and physical performance will suffer as well.
By restricting carbs, you will also be provoking hormonal shifts throughout your body. In particular, your cortisol levels will increase (to help increase blood sugar levels by stimulating gluconeogenesis and short-term insulin resistance) and your thyroid hormone levels will decrease (because fewer carbohydrates are being consumed). These hormonal changes will be most evident in the first few days of keto dieting, causing symptoms like insomnia, depression, fatigue, and a reduction in physical performance and cognitive function.
On top of all of this, it takes your body a couple of days of keto dieting before it starts producing and burning ketones for fuel consistently. In the meantime, your muscles and brain may not perform optimally because their primary fuel source is being restricted.
Fortunately, as you rehydrate your body and produce more ketones for fuel, your symptoms will dissipate and your hormones will start to balance out in a healthier way. If you’d like to learn more about what happens to your body as you adapt to carb restriction
Putting It All Together — From Conundrums to Clarity
Keto dieting is such a dramatic change from the typical westernized diet that you will probably encounter some side effects during your first week on keto.
Fortunately, there are many ways to remedy these symptoms, and once you adapt to burning fat and ketones for fuel, you will regain your energy and feel better than you did with your old way of eating.
To mitigate any issues you run into during the first week of keto, here’s what you can do:
- Use our keto calculator to find the macros that you should aim for to meet your goals.
- Restrict carbs below 10 grams of net carbs per day to get into ketosis more quickly.
- Drink plenty of water.
- Consume as many low carb vegetables as possible.
- Use intermittent fasting, high-intensity exercise, and/or low-intensity exercise to help speed up the keto adaptation process.
- Increase your energy levels by supplementing with MCTs.
- Adjust your workout regime, follow a targeted keto diet, or implement a cyclical keto diet, so that you can maintain strength and endurance.
- Prioritize sleep and stress relieving activities.