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My Real Experience on Keto and Workout

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While this low-carb, high-fat diet is widespread worldwide, there are a few critical points that physicians want you to understand before combining ketosis and workout.

Everyone has heard of the keto diet by now—the one where you can eat as much good fat as you want and almost disallowing carbs.

The keto diet, which was once reserved for people with significant health conditions like epilepsy, has gained acceptance and is particularly well-liked among athletes.

However, while it’s true that working out on keto may offer some performance benefits, scientists advise you to be aware of some extremely essential information.

Keto may affect your workouts. In the words of Ramsey Bergeron, a seven-time Ironman, and Scottsdale-based personal trainer, “you may feel like you’re floating around in a cloud.”

It will take some time for your brain to acclimate to ketone bodies instead of glucose (from carbs).

However, Bergeron advises avoiding activities that require rapid responses, such as cycling on busy highways or climbing steep hills.

Avoid Changing so many things during keto

“Keep doing what you’re doing,” Bergeron encourages. This is primarily due to the first point most individuals don’t feel fantastic on keto at first.

Because of the flu-like haziness and stomach upsets, this initial icky period has been dubbed the “keto flu” in extreme cases.

It usually lasts just a few days to something like a couple of weeks. Still, it is obviously not the best timing to try a new class or set a new personal workout best.

“When my trainees attempt something different, I always propose that they reduce the variables,” Bergeron adds.

You won’t really know what worked or what didn’t if you adjust too many things at once.

Before working out on keto, make sure you don’t starve yourself

The dietitian and health coach at 8fit, Lisa Booth, R.D.N., recommends that people should not restrict their calorie intake too much.

This is particularly important because, according to her, those on a ketogenic diet are more prone to undereating.

Also, limiting an entire food type (in this case, carbs) often results in a natural reduction in calories. And the ketogenic diet seems to have an appetite-suppressing impact.

So you may believe you’re not hungry even if you aren’t pouring enough fuel, which is carbs.

On the other hand, when you severely restrict your caloric intake while still working out, you’ll not only feel terrible, but your results will suffer as a result. 

Cardio can help you lose weight by increasing your fat-burning rate

That’s why so many individuals swear by the ketogenic weight-loss method. Booth explains that when you’re in ketosis, your body isn’t utilizing glycogen as an energy source.

“Glycogen is a carbohydrate reserve found in muscles and tissues. Ketone bodies and fat are used in their place. Ketogenic dieting can boost fat oxidation and spare glycogen.

It can also create less lactate and consume less oxygen. Therefore these will happen if you do aerobic sports such as running or bicycling on top of it.”

As a result, more fat may be burned during aerobic activity. So while it may not harm performance in the short term, he believes it will work in the long term.

Must consume a sufficient amount of FAT

The alternative is that you’ll skip out with all the advantages, and your work may suffer as a result. For Bergeron, not eating enough fat on the keto diet is like performing an Atkins diet with high protein and low carbs.

You’ll be exceedingly hungry, and losing muscle mass is a real possibility if you do this. Most low-carbohydrate diets have a negative reputation for a reason.

The lack of fat to make up for the carbs you’re not eating will make you weary and prevent you from entering ketosis.

According to Bergeron, this is why it’s crucial to get the majority of your calories from healthy fats like grass-fed meats, seafood, avocado, and coconut oil.

Ketogenic exercise can help you lose weight and improve your body composition

According to DrAxe.com fitness expert Chelsea Axe, studies have indicated that ketogenic diets with daily exercise can improve one’s body composition.

You can maximize your weight loss efforts while training in these zones if you follow a ketogenic diet. It has been demonstrated to enhance the body’s ability to burn fat both at rest and during low-to-moderate activity intensities.

In addition, it is discovered that a ketogenic diet improves the hormone “hepatic growth hormone” (HGH), which can help people feel younger and more vigorous.

The findings were reported in the Journal of Endocrinology in 2011. These findings are encouraging for keto and exercise.

However, the research was done in rats and cannot be immediately transferred into human results.

Keto Diet and H.I.I.T. Workout (High-Intensity Interval Training)

Since the ketogenic diet is high in fat and low in carbs, it has become such a fitness buzzword, many folks believe it would help them slim down quickly.

In addition, new research suggests the ketogenic diet may help athletes perform better in anaerobic conditions.

However, according to the study’s findings, following a ketogenic diet has adverse effects on exercise performance.

According to Edward Weiss, the ‘Ketogenic diet’ is widely used as a catch-all phrase for low-carb diets like Atkins. “However, there is a lot of misunderstanding in the terminology.

People frequently associate the terms “low carb” and “high protein” when discussing diet. This is similar, but it’s distinct because protein levels must be normal to be considered ketogenic.

“Right now, it’s being promoted for weight loss by the general population. It may help with weight loss, according to some research.

However, I’m concerned that all of this may be a sham. Carbohydrates make about 60% of the average American diet.

If you reduce your carb intake, you may find that you aren’t eating as much. “You may only be losing weight by decreasing calories if you remove most eating options.”

The findings could have ramifications for both those trying to lose weight and athletes hoping to better their performance on the field of ketogenic diets.

This raises an important question: What exactly does it mean for people like us?

You probably already know this, but when you’re on a low-carb diet like keto, you’ll have to change your diet to include more carbs as a fuel source to keep you going.

Make adjustments to your ketogenic diet to accommodate your workout schedule

  1. The first thing to remember is that even if you’re following a low-carbohydrate diet like the ketogenic one, you shouldn’t consume too many carbohydrates. Your body will become more adept at using the workout’s available fuel (fats in this example).
  2. Suppose you’re a more active keto dieter. In that case, you’ll be allowed a few extra grams of carbs than the average user, which will offer you an extra surge of energy during your workout. Carbs won’t slow down your keto development because your body will use them up.
  3. Due to your body’s higher metabolism rate, you may find yourself consuming more than usual. To avoid sabotaging your efforts at losing weight, make sure you’re eating the right stuff. As a result, it should go without saying that you shouldn’t work out for the first few weeks after beginning a ketogenic diet.
  4. Until your body adjusts to the increased fuel intake, your performance may be hampered. When your body switches from a sugar burner to a fat burner condition, it will get better.
  5. CrossFit and other high-intensity exercises may suffer if you follow a ketogenic diet. This means that when on keto, you should only do workouts of low intensity.

If you’re doing keto while also working out, pay attention to your body’s signals

This is particularly valid during the first few weeks of a ketogenic diet, but it applies throughout the entire process. A low-carbohydrate diet may be causing fatigue, dizziness, or exhaustion, according to Booth.

“As a person, you have a responsibility to prioritize your health and well-being. If you’re feeling lethargic, try upping your carbohydrate intake. If it reduces stress, the ketogenic diet may not be for you.”

There are numerous reasons why people choose keto or low-carb (L.C.) diets, but one of the most common is better cognition.

That’s why keto brain fog can be so aggravating. I got it. Things don’t go as planned when your intellect isn’t in top form.

Keto makes many people’s minds sharper, but this isn’t true for everyone. While this could imply that a ketogenic diet isn’t for you, it could also indicate an electrolyte imbalance, which is straightforward to remedy.

Low-carb dieters frequently experience various symptoms, including brain fog. These side effects, including headaches, irritability, fatigue, constipation, weakness, and fog of the mind, are known as the keto flu.

Can’t the ketogenic diet help with brain fog? If anything, this is designed to improve one’s mental sharpness.

My Experience

It most certainly can be for particular people. In my experience, when I’m in ketosis, I’m mentally sharper than when I’m not.

I can concentrate for more extended periods, think more clearly, and stay more focused. One of the main reasons I’ve kept on a low-carb diet is because of the advantages it provides cognitively.

Ketone supplementation has been shown to improve cognitive performance in studies that go beyond anecdotal evidence.

So it seems bizarre when the mind slows down on keto. But, contrary to popular belief, this is the case.

However, consider it in this light. Will lifting weights make you feel better right away if you’ve never done it before?

No, there isn’t. Instead, you’ll probably feel as if someone has thrown you from a moving automobile in a sleeping bag.

It takes time for your muscles to adjust to a strength-training program you’ve started. And you’ll be uneasy while you wait. But, give it some time, and you’ll notice a difference in the way you look and feel.

It takes time for your body to adjust to a ketogenic diet, just as it does for your brain. As a result, you won’t feel like your best self until it adapts.

However, if that happens, you may experience an increase in mental clarity. If you’re mired in a thick fog, this claim appears flimsy. I got it. I produced this essay to address the issue of keto brain fog and provide answers. But first, let’s get a general idea of what brain fog is.


The word “brain fog” is intentionally vague because it implies so many different things. When the circumstances call for it, it could mean:

  • Problem focusing or concentrating
  • Forgetfulness
  • I’m having a grey day.
  • You have the impression of being sluggish or “off.”
  • Being unable to concentrate

The list goes on and on.

Simply put, brain fog is linked with minor cognitive impairment. You aren’t quite yourself during brain fog.

This is true whether you’re alone or with others. Having brain fog can affect your productivity, communication skills, and mood. Others will notice.

It’s one thing to have a tight neck or a hurting knee. It’s another thing entirely to have a mind that isn’t performing at capacity.

As you may imagine, the effects of brain fog careen into every part of life. That’s why it’s so crucial to get it treated. And the first stage in getting brain fog treated is to determine what’s causing it.


Brain fog has a large number of probable reasons. We’ll talk about the keto diet soon, but keto-related brain fog is just one blip in the brain fog cosmos.

If you are having brain fog on keto, it might have nothing to do with keto. Instead, it can be a lack of sleep, a lack of activity, a dietary deficiency, or a health ailment.

Poor Sleep

Poor sleep is an excellent place to start looking. Sleep deprivation is well-documented to affect focus, attentiveness, memory, and reasoning ability.

Moreover, these symptoms can arise after just one night of short sleep.

Over Exercise

Don’t forget about exercising too. All sorts of physical exercise, it’s been established, cause suitable modifications in brain function.

Conversely, a sedentary individual is doing oneself cognitive damage by staying inactive.

Vitamin Deficiency

Several vitamin deficits might also produce brain fog. The most common is undoubtedly a deficit in vitamin B12, a chemical important for brain function.

Why is B12 insufficiency so common? One reason is that we produce less stomach acid as we age, which limits the amount of B12 we can receive from food.

For a deep dive into this topic, I recommend this essay by functional medicine practitioner Chris Kresser.

Dietary Supplements

Moving on, medications or dietary supplements may also cause a state of mental confusion. This can range from significant professional measures (like chemotherapy) to supplement usage, like melatonin to enhance sleep.

But, again, different substances impact different persons differently.

Finally, the symptom of brain fog is related to various health disorders. These include:

  • Head injury
  • Fibromyalgia
  • Diabetes\sAllergies
  • Gut dysbiosis (S.I.B.O. or candida)

The last bullet—gut dysbiosis—deserves a more significant explanation. As you may know, the stomach and brain are strongly related.

Therefore, the gut (and the creatures that dwell there) are a vital element of your neurological system.

When the gut microbiota goes astray, cognitive health might go with it.

For example, brain fog is a widely reported symptom of both small intestine bacterial overgrowth (S.I.B.O.) and small intestinal fungal overgrowth (S.I.F.O.) (S.I.F.O. is often an overgrowth of a yeast called candida).

By reducing the favorite food of harmful microorganisms (carbs), the keto diet may help with S.I.B.O., and S.I.F.O. Check our article on Keto for Gut Health to learn more.


Before dealing with brain fog on keto, I want to address a seeming contradiction. Keto is designed to boost cognitive function, not throw you in a cloud.

So which one is it? Does keto cause or treat brain fog?

Possibly both. It depends on the context.

When keto causes brain fog, it tends to happen during the transition from high-carb to low-carb dieting. This adjustment might be challenging. More on that soon.

Transition phase aside, being in ketosis has been found to provide cognitive benefits. Consider the following reported examples:

Boosting ketone levels with MCT oil improved working memory and attention in older individuals.

The ketogenic diet shows promise for enhancing cognition in Alzheimer’s and Parkison’s disease patients.

Epileptic children treated with a ketogenic diet show better alertness, cognitive function, and conduct.

Ketone-fed rats navigated a maze faster than non-keto animals.

Add this material to the ocean of joyous accounts (including mine) on keto for cognition, and you have a compelling argument that ketosis improves brain function, at least in certain people.

Okay, let’s speak about brain fog now.


A lot of individuals abandon keto due to keto flu. And of all the keto flu symptoms, cognitive fog may be the most irritating.

Here are the two leading causes and what to do about them.


Most episodes of keto brain fog are transient. We’re talking a week or fewer following the initiation of keto dieting.

Why does brain fog pop up around this time? And why does it go away? To answer, we need to understand how the brain uses energy.

The brain uses a lot of energy. The mushy hunk of gray matter is barely 2 percent of your body weight yet wants 20-25 percent of your nourishment. It’s greedy.

Glucose is your default brain fuel. When glucose is available, the brain runs almost entirely on this simple fuel. It can also run on lactate and pyruvate, but glucose handles most of the strain.

When you switch to a keto diet, you limit carbs virtually to nil, substantially reducing your incoming glucose supply.

Your body has glucose backup systems—glycogen (stored glucose) and gluconeogenesis (made glucose)—but these processes can’t make up for the shortage.

As a result, the brain receives less glucose. Which doesn’t sit well with the brain. So it’s got a lot less oomph. A mental blur is a physical sign.

That’s where ketones come in. On a keto diet, your liver burns fat to make ketones. When ketones are elevated (called ketosis), your brain runs primarily on ketones instead of glucose. So ketones are your backup brain fuel.

But the change from glucose to ketones doesn’t happen quickly. It could take a day, or it could take a week or more. So, in general, higher-carb starting points will require a more extended transition period.

The remedy: Time. A week or so of keto diets and the cognitive fog should resolve. But time isn’t also the answer—I suffered brain fog well after my change because I wasn’t obtaining sufficient fluids, notably salt.


On a keto diet, fluid and electrolyte demands go up. Why? Think insulin.

When you restrict carbs, insulin (the master energy hormone) stays low. Low insulin helps burn fat and signals your kidneys to expel more fluids and electrolytes—primarily sodium.

Brain fog, migraines, and other cognitive problems can follow if the water and sodium aren’t supplied. These are symptoms of both dehydration (water loss) and hyponatremia (low sodium) (low sodium).

In my experience, water intake isn’t a problem for most persons. Sodium consumption is. That’s because a whole food keto diet is inherently low in salt. (Salt is 40 percent sodium).

Plus, salt gets blasted as being hazardous for your heart, despite evidence to the contrary.

The Remedy

Shoot for 5 grams of sodium (2.5 tablespoons salt) each day on a keto diet. This involves drinking electrolyte water and being generous with the salt shaker.


First of all, remember that brain fog isn’t always tied to keto. Maybe you simply need more sleep, more exercise, or more clarification on a health condition.

If you’re foggy during your first week of keto, don’t panic. It’s typical and probably will resolve naturally within a few days.

If the brain fog persists, it may be a hydration issue. Be sure to get lots of electrolytes, especially sodium and potassium. Take these together with fluids to replace what’s lost on keto.

Once you’re keto-adapted and sufficiently hydrated, your keto brain fog should lift. You may even feel mentally boosted. Enjoy it.


Shakir Hasan is a fully qualified personal trainer and award winning writer, with a decade’s worth of experience under his belt. He has helped hundreds of people to meet their dietary and fitness goals, writing exercise and nutrition plans to suit any and every requirement. Shakir founded ThisIsWhyIamFit as a way to share his vast knowledge of exercises, diets, and general fitness advice.