Keto Diet - what is it and what are the pluses and minuses?


2/28/202311 min read


The ketogenic diet is one of the most discussed topics of a healthy lifestyle or sports nutrition and it can be expected that it will continue to make headlines in nutrition magazines and tabloids for some time. The ketogenic diet has also successfully come to the attention of the general public. Even companies churn out one instant keto diet after another, unfortunately such diets are mistakenly mistaken for protein diets.

The ketogenic diet is simply a phenomenon, and we hear about it from all sides. Are you confused about how it works? After reading our complete review of the ketogenic diet, you will no longer be.

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The keto diet is everywhere you look. What is its origin, and can we lose weight at lightning speed?

Where it came from, it came from. The ketogenic diet is conquering the world and making headlines with miraculous stories not only about weight loss. In fact, it didn't just pop up by accident, ads for instant keto diets attack us from TV, billboards, and internet ads.

If you give a chance to one of the instant keto diets, you are looking for your happiness in vain. Such instant keto diets are usually based on multicomponent protein preparations, which lack a number of important nutrients and lead to malnutrition and the yo-yo effect in the long term.

Where did the ketogenic diet come from and why did it start to be used?

The ketogenic diet appeared in the twenties of the last century when Dr. Russell Morse Wilder began to use it in some cases in the treatment of epilepsy in children. Although he had a lot of success with it, it was forgotten for many years, and it was not until the end of the last millennium that people started talking about it again. At that moment, however, triggered an avalanche of interest that has not faded until now, and so the ketogenic diet is still rushing at us from all sides.

What is the breakdown of nutrients within the keto diet? Fat, fat and just fat again...

... and a little protein. Somehow briefly we could describe the ketogenic diet as a dietary style.

Specific representation of macronutrients within the keto diet. Do you know how many carbohydrates you can?

  • Carbohydrates 0–5 %

  • Protein 15-20%

  • Fats 75-80%

What would the distribution of nutrients look like in terms of weight for Pepa on a ketogenic diet?

Let's imagine a young athlete Pepa, whose daily energy intake is around 2500 kcal. According to the rules of the keto diet Pep's diet can include eggs, meat, leafy vegetables, fatty cheeses, cream, nuts, seeds, or vegetable oils. No rice, pastry, do not look for fruits and sweets. Carbohydrates simply do not belong in a ketogenic diet.

Distribution of 2,500 kcal according to the principles of keto diet:

  • less than 31 g (50 g) of carbohydrates

  • 94–125 g protein

  • 208–222 g fat

With a ketogenic diet, ketosis occurs in our bodies. What is it?

During the keto diet, we have elevated levels of ketones in the blood. Due to this, a number of physiological processes in the human body are affected. How can this happen? Besides fasting or starvation, the ketogenic diet is the only eating style during which the human body switches to a regime of increased levels of ketone bodies in the blood, technically called ketosis.

During ketosis, the body produces substances in the liver called ketones (acetoacetate, betahydroxybutyrate and acetone), which supply the body (including the brain) with energy substrates instead of glucose, which is much less in the body than during normal eating.‑ Why is it profitable? The human body creates ketones from fatty acids, ie from fats, so it becomes something like a fat burning machine. And that sounds amazing, right?

Keto diet as a miracle tool for weight loss? Not. Look for a mere caloric deficit behind everything.

As part of a ketogenic diet, you may use fat as your primary source of energy, BUT the total energy expenditure remains the same as with a normal regimen. This means that at the expense of this, you will burn less carbohydrates.

In short, the law of conservation of energy still applies, and even the ketogenic diet is not a tool for breaking it.

We can burn fat as much as we want, but the condition for weight loss is still a caloric deficit. You can burn fat at full speed from morning to evening, but what good is it if you consume too much of it in your diet? To reduce the amount of fat stored on a ketogenic diet, we need to eat less energy in the diet than we expend in a day. And that's the principle of any other diet, right?

The ketogenic diet is currently considered an effective tool for reducing adipose tissue. But unfortunately, it is no miracle or fat-burning magical fire.

Why can Paoli's keto diet be effective?

  1. Reducing hunger due to eating full foods, influencing the level of ghrelin (a hormone controlling the feeling of hunger) in the blood or the specific effect of the resulting ketones on the feeling of satiety.

  2. Limited fat storage process and promotion of oxidation (burning) of fats.

  3. Increased efficiency of using fats as energy fuel.

  4. The energy required to metabolize proteins (thermic effect) and the energy intensity of gluconeogenesis (the process by which glucose (blood sugar) is formed from other substrates occurs more than usual in ketosis, because some tissues such as the brain cannot use ketones alone as an energy source).

Also, more recent studies from 2021 show that losing weight on a ketogenic diet can be a little easier. The main word is probably a reduced feeling of hunger, which is caused by the formation of cato compounds (primarily betahydroxybutyrate). Still, the key to weight loss is a caloric deficit.

Pluses of the keto diet:
  1. The most frequently mentioned benefits of the ketogenic diet include its use in weight loss. Why? A naturally occurring caloric deficit stemming from a reduced feeling of hunger leads to a reduction in fat itself.

  2. Part of type 2 diabetes management. A ketogenic diet is good at controlling blood sugar levels as a result of the cells' increased sensitivity to insulin. In Boden's 2005 study, insulin sensitivity was improved by up to 75%. Although this has been achieved primarily due to a caloric deficit, the ketogenic diet appears to be becoming increasingly popular in the treatment of type 2 diabetes.

  3. Help with neurodegenerative diseases. It has been found that adherence to a ketogenic diet can reduce symptoms and improve cognitive (brain) function in some cases of Parkinson's and Alzheimer's disease.

  4. Complementary therapy in case of cancer. A ketogenic diet can slow down the development of specific neurological cancers. This is achieved thanks to the so-called 'green card'. Warburg effect, in which carbohydrates are preferred as an energy source in cancer cells.

  5. Health of the cardiovascular system. A properly set ketogenic diet (containing mostly healthy fats) can have a positive effect on blood cholesterol levels or blood pressure, according to some studies.

Minuses of the keto diet:
  • Risk of high fat intake in the form of saturated fatty acids. Why is this a problem? Their excessive intake leads to an increase in cholesterol levels and can contribute to cardiovascular disease. Ensure sufficient intake of quality vegetable oils such as rapeseed, linseed, olive or pumpkin. The Czech Republic, Slovakia and Poland have achieved a reduction in mortality from cardiovascular diseases by replacing a large proportion of animal fats with plant variants.

  • The risk of a large intake of harmful sausages. In addition to carcinogenic nitrosamines formed from nitrites used, sausages are a source of other carcinogens (carbonyl compounds or polyaromatic hydrocarbons).

  • Insufficient fiber intake threatens even with a high-quality keto diet. It is necessary to ensure sufficient intake of vegetables, nuts or seeds, which are almost the only source of fiber in the diet. A lack of fiber may be related to a deterioration in the state of the gut microbiome. For example, Zhang (2018) noted a decrease in the number and variety of bacterial strains in the colon in children on a ketogenic diet, which is certainly not positive news.

  • The risk of insufficient intake of vitamin B, magnesium, potassium and other trace elements. Ensure sufficient intake, variety of vegetables and intake of other nutritionally rich substances, such as seeds or nuts.

  • Possible negative effect on muscle mass growth and strength performance. A 2021 study concludes that the ketogenic diet is not very good at building muscle and increasing strength performance. Compared to conventional diet, it leads to worse results.

What does the transition to a ketogenic diet look like? Expect fatigue and irritability, which will disappear after a few days.

When switching to a ketogenic diet, the first days will be challenging and unpleasant. You will probably feel tired, without energy, irritation and reduced resistance to stress may occur. After a few days, these initial symptoms pass, as the body has fully adapted to functioning on ketones at this stage.

How long does it take to adapt to a ketogenic diet?

At least 2-4 days, depending on how quickly you are able to deplete glycogen stores. Adaptation to a low-carbohydrate diet (lowcarb) takes about 5-10 days, in the case of a ketogenic diet you will probably have to wait a little longer (Goedecke, 1999).

Do you want to speed up your adaptation to the keto diet?

Give yourself 1-2 more demanding workouts right at the beginning of the diet. The body will use stored carbohydrates as a source of energy for performance and the transition to ketosis will take place faster.

Will a ketogenic diet make your brain more efficient? Not really...

Among the frequently mentioned benefits of the ketogenic diet is its potentially positive effect on brain functioning and development, as well as on improving cognitive functions.

How is it really? You can't expect any miracles, sudden enlightenment and a higher IQ

  • Brinkworth (2009) decided to test cognitive function on overweight people. After a year of testing, he concluded that the ketogenic diet did not lead to improved cognitive function, i.e. improved memory or accelerated reactions, compared to a conventional lowfat‑ diet.

  • Lacovides (2019), who compared groups of healthy people aged around 30, did not find any positive effects either. One group was on a keto diet and the other on a high-carb diet. There was almost no difference between the groups.

Ambiguous results were found in animal studies (not applicable to humans and can therefore be interpreted in a misleading way), especially mice. In his study, Hernandez observed improvements in cognitive function in mice, and Zhao and Pistell achieved completely different results in their studies. They did not notice any improvement, on the contrary, they concluded that mice on a ketogenic diet have cognitive functions or visual-spatial ideas reduced, among other things, due to higher brain inflammation.

How to understand all this? You can get a powerful brain like a NASA supercomputer with proper nutrition and adequate sleep.

With improved cognitive function as a benefit of the ketogenic diet, it's not so hot. The best factor that can improve brain function and speed of thinking remains proper nutrition, restriction of alcohol consumption and adequate sleep.

The effect of ketogenic diet on sleep is itself a topic that is often researched in scientific studies. While in the short term a ketogenic diet may make it harder to fall asleep (possibly as a result of reduced melatonin production), other studies show that a ketogenic diet may actually help with some sleep problems.

Build your own keto diet, it's easier than it may seem!

Putting together your own keto diet isn't difficult. The basis of success is choosing the optimal amount of nutrients, which is based on your daily caloric intake. You do not eat numbers in the diet, so it is also necessary to pay attention to the correct composition and selection of foods. Even in the case of a ketogenic diet, we follow the basic recommendations that remain the same for all eating styles.

Don't know your caloric intake? Then you can use nutrition calculators like IIFYM, Precision Nutrition or tools from the U.S. Department of Health and Human Services. You can also use the calculation in the article titled How to lose weight as quickly as possible? We have a step-by-step guide for you

How to convert calories into individual macronutrients?
  • You should eliminate carbohydrates almost completely. Their only permissible source is vegetables, ideally green or low-carbohydrate. The amount of carbohydrates per day should not exceed 50 g. Make sure you have enough different vegetables to cover your micronutrient ration.

  • You should not neglect proteins here either. Insufficient protein intake can be critical to your athletic results. Consume daily at least 1.3–1.5 g of protein per kilogram of weight. Depending on your sports workload, you can get up to doses over 2.0 g of protein per kilogram of weight, thanks to which you will ensure sufficient regeneration for the body. A dose of around 2.0 g of protein per kilogram of weight is standard used in a number of studies in athletes and should not cause problems with the retreat of ketosis. As a rule, you will be forced to cover your protein intake with quality products such as meat, dairy, eggs, fish, nuts and protein.

  • The largest part of the energy intake is taken up by fats. You can easily calculate their amount by leaving about 70-80% of your calculated energy intake to fats, depending on your protein needs.

  • When compiling a menu, do not be tempted to low-nutritional foods. When choosing fats, prefer vegetable oils to animal fats. Instead of sausage or fried cheese, try a vegetable salad with oil dressing, roasted meat with homemade mayonnaise or grilled salmon. You will also receive fats together with proteins from meat and dairy products. Next, choose nuts, avocados, and other high-quality vegetable oils.

  • Fill snacks with nuts, nut butters or seeds and enjoy these foods in quantities that you would not even dream of in a normal eating regime.

Illustration menu keto diet

Energy: 2,571 kcal (10,800 kJ), Carbohydrates: 40 grams (160 kcal or 680 kJ), Protein: 117 grams (468 kcal or 1,989 kJ), Fats: 213 grams (1,917 kcal or 8,094 kJ), Fiber: 18 grams

  1. Breakfast: 2 whole eggs, roasted green beans (50 g) and baby spinach (50 g) in rapeseed oil (30 ml), cherry tomatoes (100 g)

  2. Snack I: 2 walnuts (20 g) and cucumber (200 g)

  3. Lunch: beef back roast (100 g), rapeseed oil (20 ml), blue cheese (30 g), avocado (100 g), baby spinach (80 g), onion (20 g), iceberg lettuce (50 g), cherry tomatoes (50 g)

  4. Snack II: hard-boiled egg, feta cheese (25 g), 1/2 pack cottage cheese (75 g), cheddar (75 g), extra virgin olive oil (10 ml)

  5. Dinner: roasted salmon with skin (130 g), extra virgin olive oil (30 ml), iceberg lettuce (50 g), cherry tomatoes (40 g), onion (20 g), feta cheese (25 g)

What to make of it?
  • The ketogenic diet is based on high fat intake and carbohydrate restriction. Thanks to this, the body goes into a state of ketosis.

  • In ketosis, the body replaces the lack of carbohydrates by producing ketone compounds mainly from stored fat, primarily betahydroxybutyrate, acetoacetate and acetone.

  • A ketogenic diet can be beneficial for use in reduction programs, mainly due to reduced hunger and support of fat burning.

  • Fat loss is not caused by the magic fire of ketosis, but by naturally reduced energy intake.

  • Pay attention to the intake of high-quality fats based on unsaturated fatty acids, try to limit industrially processed fats or excessive intake of saturated fatty acids.

  • When adhering to a ketogenic diet, it is important to take care of the intake of nutritionally valuable foods that will allow the body sufficient intake of vitamins, minerals and trace elements that are indispensable for the functioning of the human body.

  • A ketogenic diet can be a suitable supplement to the treatment of a number of neurodegenerative diseases or specific forms of cancer.

  • Avoid powdered forms of the ketogenic diet. Unlike a properly set keto diet, these lead to too drastic a caloric deficit, not to mention a lack of fiber or essential fatty acids (omega 3). Do not expect miracles, the ketogenic diet is an effective tool for reducing diets only if you know how to use it. Choose nutritionally valuable foods and make sure that fats are properly selected primarily from plant sources in their natural form, thanks to which you will reduce the risk of cardiovascular disease.

  • Do you not like the ketogenic diet and the related limited choice of foods? Don't despair, the ketogenic diet is not superior to any other eating styles, so you have a free hand in choosing your diet plan that you will be able to follow long-term.