When you first start following a keto diet, it will take you a couple of days to enter into the state of ketosis. Depending on your activity level and on your metabolism, this usually takes two to four days to achieve.
How do you know that you’re in ketosis, though? There are a few signs and symptoms that you might experience, which will definitely help you to figure it out.
If you don’t want to measure your blood ketone levels and spend money on Ketostix and similar products, you can rely on these symptoms to tell if you are in ketosis:
#1. Rapid Weight Loss
One of the first signs of ketosis is the rapid weight loss that you will experience in the first couple of days. It usually varies from 3 to 8 lbs and most of it will be water weight. Nevertheless, it’s still a very encouraging way to begin your keto journey.
Your body stores extra energy from glucose in the form of glycogen, and each gram of glycogen is bound to 3 to 4 grams of water. This is why, as glycogen stores in your muscles, liver, and fat cells get depleted, you lose a lot of water weight (1).
Because of the diuretic effect of the keto diet, you need to stay properly hydrated and make sure that you have your electrolytes in check. Drinking enough water is very important.
After the initial period of rapid weight loss, you will continue to burn fat from using your fat stores. At this point, you will be now losing body fat, not water.
#2. Decreased Hunger
When your body switches to using fat as its primary fuel source (instead of glucose), it is normal to experience a significant loss of appetite, which will probably last for a while.
The reasons for this are not completely clear yet, but a lot of keto dieters report a diminished sense of hunger on a keto diet. This is indeed one of the reasons why it is so easy to stick to it and achieve great results.
Calories still matter and you will need to be in a caloric deficit in order to lose weight, but it becomes much easier to eat less.
The way you experience hunger will also become different – you will no longer feel ravenous if you haven’t eaten for a couple of hours, but will gradually become aware of the need to eat something, which is a much more pleasant feeling.
You may also notice that you no longer crave sugar or starchy comfort foods that you once did. This is because the keto diet balances your insulin levels to reduce the instability linked to a diet that contains glucose.
Additionally, the ketogenic diets are very satisfying because it’s high in fat. Most people do not crave sugar anymore because they finally feel satisfied from the foods they’re eating.
#3. Digestive Issues
Whenever you are making changes to your diet, your GI tract needs to adapt to the new foods that you are now consuming, and to the different proportions of macronutrients.
Depending on how drastic the change is, this might result in temporary constipation or diarrhea, and this usually resolves in a matter of a week or two.
If you’re experiencing such problems, consuming food that is rich in fiber (such as green vegetables) will usually help you resolve them.
#4. Mental Clarity and Improved Energy Levels
One of the great things about switching to a ketogenic meal plan is the increased energy that most people experience with it.
The reason behind this is that your blood sugar levels become much more stable, so you don’t experience glucose spikes and crashes, nor the sluggishness and fatigue that accompany them.
Instead, your energy is more or less constant during the day. Your mind will also feel much clearer, as the carb-induced brain fog will now be gone, and the keto diet has multiple benefits related to brain health (2, 3).
It’s amazing what limiting carbs can do to our minds!
Unfortunately, for some people, the increased energy comes hand in hand with insomnia. Fear not! It doesn’t affect everyone and it is only a temporary side effect of ketosis, until your body and mind learn how to deal with the extra energy they get from burning fat.
If you’re experiencing insomnia on keto, make sure that you are well-hydrated and have your electrolytes in check, and try to limit the sources of blue light in the evening. For example, put down your mobile devices two hours before bedtime and try not to use your computer in the evening).
A lot of people report great results with either taking a hot bath or shower, so you might want to try that. To help your body with the transition, you can take melatonin for the first couple of nights. However, we recommend using it only for a limited amount of time, as your adrenal gland might start producing less of it if you use it on a regular basis.
#6. Dry Mouth, Bad Breath and Metallic Taste
Another symptom of ketosis that can be rather unpleasant is dryness in your mouth. This is sometimes accompanied by a slight metallic taste in your mouth and an acetone breath (the so-called “keto breath”) (4).
The ketosis metallic taste might make your tongue feels weird and give you fuzzy teeth feeling.
These symptoms usually resolve after a couple of days, so don’t be discouraged.
Unfortunately, the keto breath is the last to go, but you can try brushing your teeth more often and stock up on sugar-free gum (always check the label for carbs, though). Mints can also be a good solution.
#7. Dizziness and Fatigue
Ah, the dreaded keto flu! As your body switches from using glucose to using fat, it needs some time to adapt and become fully efficient at it.
The whole adaptation process usually takes a couple of weeks. However, the fatigue you might experience in the beginning will resolve much quicker than that.
Remember that water will be flushed out of your system much more rapidly on a low carb diet, which means that you will also be losing a lot of electrolytes. This is why it is so important to make sure that you’re having enough of them. If you don’t, you might experience fatigue, rapid heart rate, and dizziness.
The electrolytes you need to keep an eye on are salt, potassium, and magnesium. In fact, with proper electrolyte supplementation, you might not even experience the keto flu at all.
If You Get Kicked Out Of Ketosis, Will This Undo Your Progress?
Not really. If you accidentally eat too many carbs once or have a cheat meal and get kicked out of ketosis as a result, you might definitely experience some side effects, such as suddenly gaining a few pounds of weight.
However, rest assured, this is almost exclusively water weight, because your glycogen stores in your muscles and in your liver just got refilled, and glycogen binds to water in our bodies.
The number you’ll see on the scale on the next day doesn’t mean that you have suddenly gained lots of fat back and undone your progress.
It’ll take you two to three days of following keto macros to get rid of it again, and you can use your newly refilled glycogen stores to have a killer workout in the gym, as it will give you an additional performance boost and also to get back to nutritional ketosis quicker.
Switching back and forth between being in ketosis and burning glucose is not a good idea, especially in the beginning of a ketogenic diet (i.e. the first 2-4 weeks), when your body is still getting adapted to it. It’ll just make the adaptation process longer and more unpleasant.
So just stick to your macros and don’t go above your carb limit, and you’ll feel better overall. And also, while getting kicked out of ketosis won’t undo your progress, it won’t help it either, especially as it will ramp up your appetite.
The most important thing to remember is that you shouldn’t punish yourself if you cheat on your diet and get kicked out of ketosis by fasting or by excessive restriction – acknowledge it, accept it, and move on.
When you go back into ketosis, you might experience some of the above symptoms again, but they’ll likely be less severe than the first time.
Keep in mind that every person is different. Our bodies adapt differently to change, and the adaptation process will also depend on your diet before you switched to keto.
Not everyone experiences all of the above symptoms when following a low carbohydrate diet. In fact, most people experience only a few of them.
The most frequent ones are water weight loss and decreased appetite, and some level of fatigue is also experienced by most people when first switching to a keto lifestyle.