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Keto Diet: What is it?

by | Mar 18, 2021 | Keto Diet | 0 comments

  1. What is it?
  2. Features
  3. Protocol
  4. How It Works
  5. Keto Metabolism
  6. Uses
  7. Example Daily Menu
  8. Weekly Menu Schema
  9. Results in 21 days
  10. Benefits
  11. Disadvantages
  12. Scientific Updates
  13. Reflections

What is it?

What is a keto diet?

The keto diet is a nutritional strategy based on reducing food carbohydrates. Which ‘obliges’ the organism to produce the glucose necessary for survival and increase fat consumption in adipose tissue itself.

A keto diet means “diet producing ketonic bodies” (a metabolic residue of energy production).

Regularly produced in small quantities and easily disposable with urine and lung ventilation, keto bodies in the ketone diet reach a level higher than average conditions. The unwanted excess of ketonic bodies, responsible for lower blood pH, is called ketosis.

The motor activity also has a positive or negative impact (as appropriate) on the ketoacidosis condition.

The presence of ketone bodies in the blood has several effects on the body; some are considered helpful in the slimming process. Others are of the “collateral” type.

There is not a single type of keto diet, and all food styles that provide fewer calories, carbohydrates, and sometimes protein than is necessary are ketogenic. They are indeed low-carb and potentially ketogenic, for example, the Atkins diet and LCHF (low-carb, high fat – low carbohydrate content, high fat).

Some types of diet are used in clinical trials (e.g., non-drug-responsible epilepsy, severe obesity associated with specific metabolic diseases, etc.). But these systems are mainly exploited in fitness and aesthetic culture.


The keto diet is a nutritional scheme:

  • Low-calorie content (energy-restricted diet)
  • Low Carb Percentage and Absolute Carb Diet
  • High percentage protein content, even if the absolute amount (in grams) is more often of medium size – remember that neoglucogenesis amino acids can be used by the liver to produce glucose
  • High percentage lipid.


What to eat in the keto diet?

The most important thing to get to the state of ketosis is to eat foods that don’t contain carbohydrates, limit those that make a few of them, and avoid foods that are rich in them.

The recommended foods are:

  • Meat, fishery products, and eggs – the basic group I
  • Cheese – II fundamental group of foods
  • Fats and oils for dressing – fifth essential food group
  • Vegetables – VI and VII the basic food group.

The discouraged foods are:

  • Cereals, potatoes, and derivatives – III key group for food
  • legumes – a fourth fundamental group of foods
  • Fruit – VI and VII fundamental food group
  • Sweet drinks, mixed sweets, beer, etc.

Typically, it is recommended to maintain a carbohydrate intake of 50 g/die, organized ideally in 3 portions with 20 g.

A rather strict guideline for a proper diet of ketogenic provides for energy distribution of:

  • 10% carbohydrate
  • 15-25 percent protein (not forgetting that proteins, including glucogenic amino acids, also contribute to sustaining the blood glucose level)
  • 70 percent or more fat.

How do you know you’re in a mess?

Potential state of ketosis, the urine (with appropriate urine strips), blood (ketone blood meter), or breath (ketone analyzer in the breath) may be tested. But you can also rely on specific “detector” symptoms, which do not require any testing:

  • Dry mouth and thirst
  • Increase in diuresis (for acetoacetate filtration)
  • Acetonic breath (for the presence of acetone) escaping through our breath
  • Reduced appetite
  • Weakness.

How many ketones must be in the blood?

There is no real distinction between ketosis and non-ketosis. The level of these compounds is influenced by diet and lifestyle. However, it can be said that there is an optimal range for the proper functioning of the keto diet:

  • Below 0,5 mmol of ketones per liter of blood is not considered as ketosis.
  • Between 0.5 to 1.5 mmol/l is light ketosis.
  • With 1,5-3 mmol/l, the ketosis is defined as optimal.
  • Values of more than 3 mmol/l, in addition to not being more effective, compromise health (especially in the case of type 1 diabetes mellitus)
  • Values over 8-10 mmol/l are difficult to achieve with diet. Sometimes they are produced in diseases or by inadequate physical activity; They’re also related to very severe symptoms.

How It Works

How does the diet work?

The mechanism for the functioning of the ketodiet is based on reducing calories and carbohydrates, which, in combination with a fair protein level and a high-fat content. Should improve cell lipid oxidation and, therefore, total fat consumption by optimizing slimming. The production of ketonic bodies, which must be strictly controlled, has moderating appetite stimulation – because of their anorexic effect.

Keto Metabolism

Energy production overview

Cell energy production is achieved by the metabolization of some substrates, primarily glucose and fatty acids. This process mostly starts in the cytoplasm (anaerobic glycolysis – without oxygen) and ends in mitochondria (Krebs cycle – with oxygen – and ATP recharge). Note: muscle cells are also able to oxidize reasonable amounts of branched amino acids. However, there are two key aspects to be emphasized:

  • Some tissues, like the nervous one, work almost exclusively on glucose
  • The correct cell use of fatty acids is subject to glucose, which, if deficient, is produced from the liver by glucogenesis (from substrates such as glucogenic amino acids and glycerol).

Note: glucogenesis alone cannot meet the metabolic requirements of the whole organism definitively in the long term.

That is why carbohydrates, although they cannot be called “essential.” must be regarded as indispensable nutrients and recommended a minimum intake of 180 g/die. (the minimum amount to guarantee the full functionality of the central nervous system).

Residual ketone bodies

Let’s explain how chronic bodies are freed.

During energy production, fatty acids are first reduced to CoA (coenzyme A) and then entered the Krebs cycle. Here they bind to oxalacetate to achieve further oxidation until they release carbon dioxide and water. When the production of acetyl CoA by lipolysis exceeds the absorption capacity of oxalacetate, so-called ketonic bodies are formed.

Note: Each ketonic body consists of two acetyl CoA molecules.

Types of ketonic bodies

Chemical bodies are of three types:

  • Acetone
  • Acetoacetate
  • 3-hydroxybutyrate.

Disposal of ketonic bodies

Ketonic bodies can be further oxidized, particularly by muscle cells, heart, and in a small part by the brain (which uses them mainly with glucose deficiency), or disposed of with urine and lung ventilation. Needless to say, increasing the working load of the kidneys will also increase by increasing the ketonic bodies in the blood.

Suppose the production of ketonic bodies exceeds the disposal capacity of the body. In that case, they accumulate in the blood, resulting in so-called ketosis.

ketosis, ketoacidosis and metabolic acidosis

Also called ketoacidosis, this condition lowers the blood pH by defining the typical pattern of metabolic acidosis (typical for untreated diabetes). In extreme cases, acidosis can lead to coma and even death.

Ketoacidosis and activities

The role of motor activity in ketoacidosis is, in a way, contradictory. On the assumption that keto diet is still a metabolic force – which can lead in the long run to unpleasant consequences. Even in a young and well-trained organism – it is necessary to specify that:

  • On the one hand, intensive physical exercise increases the energy demands of glucose by encouraging the production and accumulation of ketonic bodies.
  • On the other hand, moderate physical activity increases the oxidation of the ketonic bodies by opposing their collection and the adverse effects they may have on the body.


We have already said that the organism still needs glucose and that if it is not used in the diet, it must be produced with glucogenesis. Glucose is also necessary for the completion of lipid oxidation.

Gluconeogenesis is a process that results in glucose being formed from the carbonous skeleton of certain amino acids (known as glucogenic, or which give rise to oxalacetate). To a lesser extent, including glycerol and lactic acid. This process ensures a constant energy supply even in glucose deficiency conditions. Still, it forces the liver and kidneys to work more to eliminate nitrogen.


Application of the keto diet

This food strategy is mainly used in three (very different) contexts:

  • Slimming (better under medical supervision)
  • Food therapy of certain metabolic diseases, such as chronic hyperglycemia, hypertriglyceridemia (only under medical care), arterial hypertension, and metabolic syndrome (never in the liver and/or kidney disease or suffering)
  • Reduction of symptoms associated with child epilepsy (only when the subject is not responding to pharmacological therapy and only under medical check).

Example Daily Plan

Keto diet daily plan example

Examples of daily menus of a keto diet can be found in the article:

To find out more:

Keto Diet Plan Example

Weekly Plan

Weekly plan scheme of the diet

For more information on the weekly plan scheme of a keto diet, please refer to a dedicated article:

To find out more:

Keto Diet and 7-days Plan

Results in 21 days

Results in 21 days of a keto diet

As we’ve said, there are different kinds of a keto diet, and not all of them have the same results.

And that’s because, regardless of your personal aptitude, the keto diet is a system that requires quite accurate monitoring and control. Moreover, it cannot (or should not) be prolonged too long. They are generally well-tolerated about three weeks, or 21 days.

For this reason, a book entitled “21-Day KetoDiet Weight Loss Challenge” was produced and published: Recipes and Workouts for a Slimmer, Healthier You’. The text contains a hundred recipes and the entire food management over time. Various training protocols facilitate weight loss while keeping the muscle mass as possible.

There is no need to dwell on the evaluation of this method; as I said, a keto diet is a rather delicate system and should not be underestimated. It is therefore impossible to standardize this method for the entire population. Leaving the complete management of the keto diet to consumers is wrong because it is easily misleading. This does not mean that it does not work, but rather that it is not an appropriate solution.


Benefits of a keto diet

The benefits of a keto diet can be:

  1. Facilitates slimming by:
  • Reduction of total calories
  • Maintaining constant glycemia and insulinemia
  • Increase in energy fat consumption
  • Increased overall caloric cost for increased specific dynamic action and “metabolic work”.
  1. It has an anorexic effect
  2. It can help counter symptoms of epilepsy that don’t respond to drugs, especially in children.


Disadvantages of a keto diet

The keto diet can also exhibit several disadvantages, most of which depend on the levels of ketonic bodies present in the blood:

  • Increased filtration of the kidney and diuresis (excretion of ketonic bodies and nitrogen slag)
    • Dryness tendency
    • Increased kidney workload
    • The possible toxic effect on kidneys by ketonic bodies
  • Possible hypoglycemia
  • Possible hypothesis
  • Keto-influenza or keto-flue in English; It’s a syndrome related to the poor adaptation of the organism two to three days after the onset of the keto diet. Includes:
    • Headache
    • Fatigue
    • Vertigo
    • Light nausea
    • Irritability.
  • In the most sensitive sectors, increased possibility of fainting (due to the two previous ones)
  • A greater tendency to:
    • Muscular cramps
    • constipation
    • Heart palpitations
  • Increased liver workload, increased glucogenesis, transamination, and deamination processes
  • In the case of intense and/or prolonged motor activity, muscular catabolism
  • It’s unbalanced, and it tends to limit the intake of some very important nutrients.
  • It may be particularly harmful to:
    • Malnourished persons such as persons affected by a food-behavior disorder (DCA)
    • Type I diabetes
    • Gravis and nutria
    • Those who already suffer from liver and/or kidney diseases.

Scientific Updates

Carbohydrates: do they compromise health and promote mortality?

Looking at and carefully comparing the list of benefits with the list of disadvantages, it seems that the keto diet is not a true “manna from heaven.” In fact, this method is counter-indicated in several situations. It also requires a certain “individual sensitivity”, or the use of analytical tools that ensure that they fit perfectly into the “ideal host”. It is certainly a very cumbersome and unspontaneous strategy. However, it is still widely used in slimming down and in food therapy for chronic hyperglycemia.

Scientific research suggests that, if used correctly, a keto diet can not only be useful but also remedy some of the damage caused by carbohydrate-rich diets obesity, diabetes mellitus type 2, hypertriglyceridemia, etc.

Study PURE of Dehghan et al., 2017

The PURE (Dehghan et al., 2017) is a perspective (or cohort) study that has observed over 135,000 participants from 18 countries for many years. Excluding those with pre-existing cardiovascular diseases (except diabetes), after a 7,4-year follow-up since the commencement of observation, more than 10,000 deaths or cardiovascular events (such as heart attack and stroke) related to the parameters of the start of the study (socio-economic factors, food, and motor activity questionnaires) occurred. Carbohydrate intake has been found to increase total mortality while lipids (unsaturated and saturated) decrease it. No link was found between fat consumption and cardiovascular events or other related mortality, except saturated fats, which unexpectedly associated with a lower risk of stroke.

The release of insulin from glucose intake and the corresponding reporting cascade’s activation can be considered the main reason for the increased yield of carbohydrates to increase mortality. As shown by the high incidence of cancer in diabetics, hyperinsulinemia is a very important malignant growth factor.

Reduction of glucose absorption

From a therapeutic perspective, if carbohydrates are important factors in promoting mortality, the reduction of total income and the inhibition of the absorption and metabolism of carbohydrates should prolong life.

Acarbose is an inhibitor of alpha-glucose, an intestinal enzyme that releases D-glucose from complex carbohydrates (mainly starch). It’s been used to treat diabetics to limit the absorption of carbohydrates in the gut since the 1980s. In line with the role of carbohydrates in compromising health, acarbose has proven to prolong life in mice (Harrison et al., 2014)

Kidney 2 sodium-glucose co-transporter inhibitors (SGLT-2) promote the removal of D-glucose from the blood through urine. These newly developed inhibitors are used to treat diabetics. The potential effects on the lifespan of human beings or organisms have not yet been published, but appear to be justified.

Diabetic metformin, currently under investigation regarding the extension of life span (TAME study), reduces glucose (gluconeogenesis) production from the liver and results in a reduction in glycemia.

Nutrient combination

In mice, the near-complete removal of carbohydrates (< 1%) to obtain a keto diet has improved life expectancy compared to a high-carbohydrate diet. On the other hand, Roberts et al., 2017, observed that reconstituting even 10 percent of energy in simple sugars disappears from this positive effect. By replacing sugars with complex carbohydrates, the parameters improve significantly; It’s the sugar that has the worst effect. It has been shown that combining a high-fat diet with medium percentages of simple sugars produces negative results. However, the worst has come from a very high level of fat and sugar. Also, there was an extension of the lifetime of mice by replacing nutrient proteins with carbohydrates, independent of total calories (Solon-Biet al., 2014). These studies suggest that food sugar can be a significant but not unique limiting factor for rodent health.

Criticism of the study

The study was also criticized for manipulating the statistical effect of its results. In particular, the nutritional habits dependent on the income and geography of specific subgroups would not apply to Western high-income companies (which had been included in the PURE). In fact, Dehghan et al. (2017) did not analyze what specific sources of carbohydrates (refined sugar/carbohydrates or whole cereals) can contribute to the harmful effects of glucose. And how income can influence the quality of dietary choices. However, an additional revision on family income and wealth and the socio-economic status of the respective country was later proposed. Demonstrating that these variables had no influence on the study’s main findings (Appendix, p. 34, Dehghan et al., 2017).

Conclusion of the study

The PURE study team believes that the current nutrition recommendations, especially for refined carbohydrates and sugar, should be radically reconsidered. Also, pharmacological options to simulate low-carbohydrate nutrition (i.e., without the need for an effective reduction in carbohydrate intake) should be considered a useful and practical approach to changes in nutrition habits for the general population.


Keto diet: would you?

Avoiding glucose from the diet and forcing the body to use the cheapest amino acids is a rather “questionable” strategy. Because it poisons the whole organism. It tends to needlessly strain the liver and kidneys, making the nervous system and the muscles less efficient.

On the other hand, keto diets’ potentially serious adverse effects are more limited than many believe. Or rather, the short-term keto diet alone does not cause renal insufficiency, liver failure, reduction of basic metabolism and thyroid impairment, bone demineralization, etc. What could happen in the long term remains the subject of studies. Of course, a keto diet must not be understood as a definitive food strategy, especially given the contraindications it can have in certain situations.

But there is no doubt that all this works, besides keeping the glycemic-insulin levels low (responsible, along with the excess caloric, for adipose storage). Increases the amount of burned calories, stimulates hormone secretion, and the production of metabolites that promote fat disposal and suppress appetite. For all these reasons, the “slimming” effect of the keto diet is, on balance, high.

The keto diet works right away but puts the organism under continuous and unhealthy stress. If poorly designed, particularly when misallocated or excessively restrictive, the diet must be abandoned and replaced by other less dangerous and equally effective food strategies.

Although it’s also used in epilepsy treatment that doesn’t adequately respond to drugs, a keto diet can be particularly damaging in other settings. It is one of the most widespread ‘extreme’ food strategies in certain dietary disorders (DCAs). If carried out by a person suffering from type 1 diabetes mellitus (though there would be no reason for it). It requires a lot of attention and medical support because it could have serious health consequences. Also, because it is heavily unbalanced, it can compromise the nutrition demand of the pregnant woman or the nanny.

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