10 Signs You’ve Entered Into Ketosis

When you’re on the ketogenic diet, your entire metabolism shifts. Below, I’ll detail the most common signs and symptoms of transitioning into ketosis, such as “keto flu,” “keto breath,” and changes in your energy levels.

Ketosis is the desirable state in which your body burns fat instead of carbs as a fuel source. Experts recommend keto for rapid weight loss, cholesterol improvement, higher energy, mental clarity, and even epilepsy. 1, 2)

But transitioning from carb-burning to fat-burning may take 2-4 days or even 1-2 weeks, and there are short-term ketosis symptoms you can prevent or anticipate. Keep reading for keto diet symptoms and how to test ketone levels.

1. Weight Loss

Even though keto is a high-fat diet, you’ll likely lose significant weight in your first week or 2 of keto. First, you’ll lose water weight; then, you’ll experience fat loss.

Keto dieters initially lose water weight because they’re burning through their glycogen stores. Glycogen is your body’s stored form of glucose (sugar). On keto, you don’t need very much glycogen/glucose; instead, your body turns to stored fat for most of its energy. (3)

Free tool: Measure Your Glucose Ketone Index

Glycogen is mostly water — 3 molecules of water for every molecule of glucose — so when you burn through your glycogen stores and don’t refill them by eating carbs, you can lose several pounds of water weight. (4)

2-3 weeks into keto, your glycogen stores will be gone, and you’ll start burning through body fat due to the following reasons:

• Low-carb, high-fat dieting lowers your blood sugar levels.
• Low blood sugar levels reduce your insulin levels.
• Low insulin signals fat burning and ketone production. (5)

Although weight loss may slow down between the glycogen-burning and fat-burning stages of keto, this fat-burning state drives sustained keto weight loss. The evidence speaks for itself:

• Women on keto lost more weight than women on high-carb calorie restriction. (6)
• 16 adolescents lost more weight following a low-carbohydrate diet than a low-fat diet over twelve weeks. (7)
• A 24-week ketogenic diet improved body composition (less fat, more muscle) in obese people. (8)

2. Bad Breath

One of the ketone bodies you produce while on the keto diet is acetone. When you’re first transitioning into ketosis, you may release acetone through your breath. Though not everyone experiences “keto breath,” this acetone breath is a common side effect of ketosis.

Acetone is the main ingredient in nail polish remover. It smells sweet, fruity, and a little bit like gasoline. If your breath smells that way, there’s nothing wrong. You’re likely just producing more acetone than usual as your body adapts to keto.

The good news is that keto breath is a sign your body is in ketosis, and it usually goes away after you’ve been keto for a few weeks.

3. Reduced Appetite

Once you’re keto-adapted, you’ll likely crave fewer snacks, sweets, and treats. That’s because a high-fat, low-carb diet reduces appetite in several different ways: (9)

• Lowering ghrelin, your hunger hormone
• Reducing neuropeptide Y, an appetite stimulator in your brain
• Boosting CCK, a peptide that makes you feel full

If hunger decreases, and you find it’s easy to go 5-8 hours without food or cravings, there’s a good chance you’re in ketosis. Decreased cravings can also reduce unnecessary snacking, further promoting weight loss and lowering your risk of obesity.

4. Keto Flu

Keto flu describes the flu-like symptoms caused by your body’s transition from burning carbs to burning fat for energy.

It takes your body a few days to switch over, and during that time, there’s a lot going on with your biology. Your kidneys expel water and electrolytes as your glycogen stores deplete. You often get sugar and carb withdrawal, which feels similar to caffeine withdrawal. (10)

Symptoms of keto flu may include:

• Short-term fatigue
• Insomnia
• Brain fog
• Low energy levels
• Irritability
• Dry mouth
• Frequent urination
• Sugar cravings

Keto flu may last 2 weeks after you cut carbs from your diet.

You can do a few things to address or avoid keto flu symptoms:

• Increase your water intake. (11)
• Take a well-formulated electrolyte.
• Don’t cut calories until you’re fully in ketosis. Load up on healthy fats as needed to feel full and energetic.

If you’ve followed the best practices for starting keto, and you’re still experiencing keto flu symptoms after 2 weeks, consider backing off. Keto isn’t perfect for everyone, and it may not mesh well with your unique biology.

5. Changes in Energy Levels

There are multiple ways that keto can change your energy levels. Though the early transition into ketosis may cause fatigue, you should feel increased energy once you’re in ketosis.

On keto, your blood sugar stays consistently low and stable, which means you don’t get the energy rollercoaster of sugar highs and sugar crashes.

Ketones are also an exceptionally efficient energy source. When burning ketones, your mitochondria (the powerhouse of the cell) produce more energy and with fewer free radicals (inflammatory byproducts of metabolism) than when burning glycogen. (12)

If you experience steady, plentiful energy throughout the day, odds are you’ve switched from burning sugar to burning fat for fuel.

6. Frequent Urination

Keto dieters tend to have increased thirst, dry mouth, and more frequent urination for a couple of different reasons.

In the initial stages of the keto diet, you will likely experience frequent urination as your body sheds water weight from burned glycogen.

Once you’re in ketosis, your body’s producing ketones for energy. Ketones are diuretic, meaning they cause more frequent urination. Ketones also change your urine to a darker color, which is perfectly healthy.

How long does frequent urination last on keto? Many people on keto experience frequent urination (water flushing) for the first 1-2 weeks of the diet. Most people’s bodies get used to the ketones and biology changes and enjoy less frequent urination as the diet continues.

7. Muscle Cramps

If you cramp up on keto, don’t panic. The causes are probably easy to fix.

Muscle cramps in keto are typically related to dehydration and depleted electrolytes. (13) Since keto causes frequent urination and you’re losing water weight, keto dieters must replenish lost fluids to avoid muscle cramps (and other dehydration symptoms like headache).

Drink plenty of water and take a high-quality electrolyte supplement with potassium, magnesium, and sodium. 

8. Digestive Issues

Some people experience digestive distress, including constipation or diarrhea, in the first couple of weeks of keto. Keto-related gastrointestinal problems may be caused by:

• Low fiber (most likely)
• Dehydration
• Shifts in your gut microbiome
• Sensitivities to new foods in your diet

Fiber is the indigestible material that feeds gut bacteria and stimulates healthy bowel movements. Inadequate fiber can lead to myriad digestive issues. (14)

When you cut out carbs, you’re also cutting out many fiber-rich foods. Replace high-carb fibrous foods with low-carb fibrous vegetables like kale, broccoli, and asparagus. (Remember, don’t count carb intake from fiber when determining net carbs since fiber doesn’t fully digest.)

For more dietary guidance, check out this list of keto-approved foods.

9. Keto Insomnia

You may have trouble sleeping during keto transition. Usually, it’s because of carb withdrawal. Sugar is physiologically addictive, and cutting it out can cause withdrawal symptoms, one of which is insomnia. (15)

Your body may also be protesting the lack of carbohydrate intake because it hasn’t adapted to burning fat yet. As a result, your brain may release cortisol in the middle of the night, telling you to wake up and find food.

Insomnia usually resolves after 1-2 weeks of keto dieting. In the meantime, you might try melatonin, a safe and effective natural sleep supplement. (16)

10. Mental Clarity

Both glucose and ketones cross the blood-brain barrier to fuel your brain. But sugar causes brain fog and inflammation when you consume too much of it. (17)

Ketones have the opposite effect. In one study, for example, elderly adults achieved better mental performance after ingesting MCT oil, a compound that goes straight to your liver for ketone production. (18)

Mental clarity is one of the most commonly cited benefits of a ketogenic diet. If you feel as though your focus has improved, that could be a positive ketosis symptom.

How Long Keto Symptoms Last

It takes about 2 days to 2 weeks for your body to enter ketosis. Symptoms of transitioning into ketosis may subside as quickly as 2-4 days, but you may experience symptoms for up to 2 weeks. You may boost your ketones in those first weeks with a ketone drink supplement.

If 2 weeks pass, you’re following a healthy keto diet plan, and you’re still facing keto flu symptoms, the keto diet may just not be for you.

Read More: How Long Should You Be On Keto?

Measuring Your Ketone Levels

The signs and ketosis symptoms we discussed above are subjective ways to tell whether or not you’re fat-adapted. If you want hard data on your metabolic state, you can use the following tests to measure your body’s ketone production.

Below are the three most common ketone measurement methods.

Blood Testing

Blood testing is the gold standard and most accurate way to measure ketosis. You can have your blood ketone levels measured at the lab or do it yourself at home with a blood ketone meter and test strips.

Note: At-home methods call for a pinprick and a drop of blood.

Blood testing measures blood levels of beta-hydroxybutyrate (BHB) — your primary energy ketone. Here are what your BHB levels mean:

• BHB levels above 0.7 mmol/L, you’re still transitioning into ketosis
• BHB levels above 1.0 mmol/L, you’re in deep nutritional ketosis

Urine Testing

You can also use test strips to determine the ketone levels in your urine. Urine testing isn’t as accurate as blood testing, but it’s cheaper and more convenient. Plus, it doesn’t require pricking yourself with a needle.

Generally, urine strips turn a certain color (displayed on the bottle) when they make contact with your ketogenic pee. The color indicates your depth of ketosis by measuring levels of acetoacetate — the predominant ketone excreted in the urine.

The best times to measure urinary ketones are early in the morning and after dinner. (19)

Breath Testing

Ketone breath tests measure acetone in your breath. Remember acetone? It’s the ketone that can give you keto breath.

In one study, researchers showed that breath acetone is correlated with blood and urinary ketone measurements. (20)

Ketone breath testing is newer than other methods. It’s less accurate than blood testing, but it’s a convenient and helpful way to test your ketone levels.

Ketosis vs. Ketoacidosis

Ketosis is the goal of the keto diet, but some people confuse it with diabetic ketoacidosis (DKA). Here are the differences:

• Ketosis is your body’s state of burning fat instead of glucose for fuel. It promotes weight loss, mental clarity, and more consistent energy levels.
• Ketoacidosis is the life-threatening state in which your body produces very high levels of ketones, building up acid in your blood. It is most commonly a complication of both type 1 and type 2 diabetes and should be treated as a medical emergency. The keto diet does not lead to ketoacidosis if adhered to correctly, but unhealthy keto practices may pose a dangerous risk. Seek immediate medical attention if you suspect a build-up of acids in your blood.

Talk to your healthcare provider about your unique risks of diabetic ketoacidosis, as well as any major dietary changes you want to make.

FAQs

Do calories matter on a keto diet?

You don’t have to count calories to stay on a keto diet. You only have to count net carbs (total carbohydrates minus carbs from fiber) to maintain ketosis.

You may want to count calories if you are trying to lose weight, though, to keep your caloric consumption below ~2,000 per day. Consuming more calories than you burn can lead to storing fat and gaining weight.Read Next: Carb Blockers — How They Work, Benefits, and Risks

Why do some people take longer to enter ketosis?

There are a number of factors that mean some people take longer to enter ketosis:

• Advanced age
• Low activity levels
• High carbohydrate consumption
• Insufficient fat consumption
• Slow metabolism
• Chronic stress

What are the symptoms of carb withdrawal?

There are benefits to cutting carbs, but there may also be the following symptoms:

• Fatigue
• Headache
• Dizziness
• Nausea
• Diarrhea or constipation
• Mood swings
• Appetite changes

The Bottom Line

There are a variety of different signs and symptoms indicating you’re in ketosis, as well as objective tests to figure out your ketone levels.

Ketone testing can be helpful, but it’s not necessary if you don’t want to go through the trouble. As a rule of thumb, you should be able to get into ketosis after limiting carbs (everyone has a different carb limit) for about two weeks.

Check out this simple, complete guide to starting a ketogenic diet. It’s easier than you might think, and after the initial adaptation phase, there’s a good chance you’ll feel amazing.

If keto flu symptoms persist, consider a more balanced diet called modified keto, which incorporates more carbs while still providing many of the wellness and health benefits of ketosis.

Try our Keto-Boosting Collagen Powder today!