Ketogenic diet: what is it and how does it work?

The ketogenic diet is a nutritional strategy that provides a low intake of carbohydrates. Perhaps this is why it often sought after by those who want to lose weight? What is keto diet? In reality, it is not the exclusion of carbohydrates that makes the valuable ketogenic diet for weight loss: if it does lose weight, it is because it is low calorie, no other secret.

For athletes, preserving muscle mass is also addressed: can (and how) the keto diet meet the needs of those who train in the gym?

What is the ketogenic diet? What is it about?

A ketogenic diet is nothing more than a diet capable of inducing a specific adaptation of the liver that begins to produce a more significant amount of ketone bodies and shifts the metabolism from the prevalent use of glucose to that of lipids.

More concretely, it is a diet that limits carbohydrates below a more or less low threshold. The intake of proteins and fats is variable depending on the subject and the objectives of the diet. Although proteins can have an anti-ketogenic effect due to their ability to promote insulin, it challenging to counteract adaptation to ketosis if carbohydrates are kept low, even with high amounts of protein.

How does the ketogenic diet work? What is it for?

Under “normal” food conditions and in a state of physiological, nutritional health, the body uses a mixture of fats, proteins, and carbohydrates for energy purposes. However, when carbohydrates remove from the diet or are present only in small quantities (maximum 100 grams per day even if in reality most ketogenic diets provide a much more limited introduction: about 30-50 g / day), stocks carbohydrates in our body tend to run out quite quickly.

As a result, the body adapts and uses an alternative fuel to glucose to a greater extent to provide energy. One such fuel is free fatty acids (FFAs), which most tissues in the body can use.

Most tissues in the body can use by the degradation of hepatic glycogen, then by the increase in gluconeogenesis, which exploits non-glucose precursors, including mainly some amino acids, to produce glucose. However, prolonged and robust gluconeogenesis for too long results in excessive proteins, including muscle, degraded to produce amino acids and subsequently glucose. This is why after about 1-2 days, there is also a sharp drop in gluconeogenesis to reduce protein degradation and preserve lean mass.

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How, then, does the body avoid having problems due to glucose deficiency?

The point is that the glucose requirement itself is significantly reduced due to physiological adaptations to fasting:

1. Reduction of the metabolic rate
2. Greater use of FFAs

The fatty acids, therefore, will try to replace the energy purposes of glucose. However, not all organs can use FFA: for example,  the brain cannot use fatty acids for energy purposes but can adapt to ketone bodies. When the latter is produced in more significant quantities and at a greater rate (ketone bodies come from the metabolism of fats), they accumulate in the blood, inducing a ketosis metabolic state.

Further Decrease about keto diet

Simultaneouslyketosis metabolic stated a further decrease in glucose use and its production and consequently decreased the degradation of proteins used for energy purposes. When adaptation to ketosis leads to less protein being used for energy, there is a positive effect on saving muscle mass.

In any case, it must be clarified that adaptation to ketosis has not been shown to lead to more significant advantages than other low-calorie, high-protein foods. However, it is also not as ineffective as a good portion of the proponents of high-carb diets would like to believe.

There is no metabolic advantage or disadvantage over a   non-ketogenic protein diet for fat loss and muscle protein savings. One of the reasons this dietary approach is adopted is that it is considered an easy diet.

How long does it take to go into ketosis?

In fasting conditions, the glucose contained in the liver and keeps the blood sugar stable keeps us or even earlier if you exercise. If not many carbohydrates are introduced, there is no glucose in the liver, but the cells still need energy! Hence, the body begins to adapt (state of ketosis) to use fatty acids and ketone bodies in place of glucose as an energy source.

The body starts consuming fat as its primary fuel after about three weeks. For this reason, the principles of ketosis (fat consumption, protein saving because gluconeogenesis decreases) only valid when this time frame is reached.

Ketogenic diet and effects on insulin and glucagon

As for the effects on hormones, adaptation to ketosis mainly affects two:  glucagon and insulin.

L ‘ Insulin is a hormone responsible for the storage of nutrients from the blood to target tissues. Still, the more precocious and powerful effect is inhibition of lipolysis in adipocytes of the white level by acting on the hormone-sensitive lipase (HSL). This is an enzyme responsible for the hydrolysis of triglycerides ( TAGs ) into fatty acids and glycerol.

The glucagon is a hormone that stimulates the body to use and release the glycogen stored in the liver in glucose. It is important to remember that the hepatic glycogen is not the muscle since it uses only by the muscle fibers for their physiological activity. At the same time, the liver is the organ that sorts the carbohydrates into all the other tissues according to their needs and glucose availability.

When carbohydrates are removed from the diet,  insulin levels drop, and glucagon levels rise. This causes an increase in FFA release by the adipocytes and an increase in the uFA by the liver precisely due to reducing the anti-lipolytic effect of insulin.

This last adaptation then leads to the production of ketone bodies and the metabolic state of ketosis described above.

Benefits and advantages of the ketogenic diet

If you think it can help you lose weight and maintain muscle mass, the ketogenic diet works. However,  the metabolic benefits of ketosis are disproved, so it is wrong to think that a ketogenic diet is no matter how better (or worse) than another fat loss diet – there will be people who are comfortable with a ketogenic approach. And people who would optimize their results by following different dietary strategies.

One of the advantages of the ketogenic diet is the increase in satiety, better food control, and greater compliance with the diet. However, compliance is due to the theoretical satiating effect of nutrients, meals, or diet, and the food choice is consumed moan freely.

A ketogenic diet inevitably precludes consuming a large variety of foods, so it is not always an easy diet for people to follow. It is usually the opposite. Furthermore, the satiating effect of ketogenic drugs appears to be primarily (if not totally) attributed to protein intake, meaning that it is the protein and not the ketogenic itself that has an advantage on this aspect, suggesting that other diets, non-ketogenic, can bring the same benefits on the regulation of hunger and satiety that we find in ketogenic diets.

However, it should be noted that the ketogenic diet is considered safe, the side effects are minimal and temporary. Clearly, like all particular approaches, they provide contraindications in some pathological cases.

Finally, it must be considered that the effectiveness of ketogenic diets also depends on how they are structured since there are different protocols and variants.

Contraindications, harms, and side effects of the ketogenic diet

The ketogenic diet is particularly contraindicated in lipid metabolism disorders as ketogenic dietary protocols provide for an abnormal intake of lipids. Therefore, for all those subjects with carnitine deficiency,  carnitine palmitoyltransferase I  and  II  (the enzyme system that allows the transport of fatty acids into the mitochondrion where beta-oxidation occurs),  3-hydroxy acyl-CoA,  pyruvate carboxylase must not follow a ketogenic diet.

There are also no particular contraindications for a ketogenic diet except to emphasize that the application of this dietary strategy in the presence of some diseases, such as diabetes, is particularly complex and requires careful monitoring and some changes to traditional protocols.

Underlying the concern about kidney damage induced by a ketogenic diet is the belief that a higher protein intake than the RDAs for sedentary subjects (0.8-1g / kg) can cause damage to the renal system and progressive loss of functional capacity. Kidneys. In reality, the scientific literature has long denied these hypotheses, at least for protein inputs (even very high) for a few weeks or months, while very long-term effects are not fully known due to the lack of adequate studies.

Ketogenic Diet: What is the keto diet

One concern often raised by doctors about the potential adverse effects of a low-carb, high-protein diet is the alleged potential liver damage from excess protein.

In reality, scientific research is not very substantial in this regard. In one of the few longer-term studies (only four weeks anyway), no changes in liver enzymes were observed following a ketogenic diet. The other long-term studies concern epileptic children who follow a ketogenic diet, and even in this case, no liver damage has ever occurred.

However, in intellectual honesty, these studies are not 100% reliable. It cannot say with certainty that ketogenic drugs do not have long-term effects (years) on liver function. At the same time, it is unfair to do psychological terrorism on this topic. At the moment, there is no evidence that a ketogenic diet adequately observed can damage the liver.

Insulin resistance

Although low carbohydrate diets, and thus ketogenic diets, generally tend to normalize insulin and glucose levels in the blood, it should bear in mind that when carbohydrates reintroduced, there is an ever, this phenomenon should occur no when carbohydrates reintroduced lead to the conclusion that it is better not to introduce carbohydrates into the diet for life. If anything, it should make nutrition experts think and push to search for other methods to improve glucose sensitivity and the functionality of insulin mechanisms.

There is little research regarding the physiological effects of carbohydrates reintroduced after a long period of the ketogenic diet. Plant based protein powder Still, it seems that the initial physiological response given by the reintroduction of carbohydrates is similar to what happens in type II diabetics, that is, fluctuations in the concentration of blood glucose ( glycemia ) and hyperinsulinemia. However, these responses did not occur in all studies. These responses are prevalent in those individuals who previously had (I mean before following the low-carb diet) management problems: glucose and some degree of insulin resistance.

More than a side effect, or possible damage to the body due to the ketogenic diet, it would be more correct to say that in many cases, a ketogenic diet is not an optimal strategy to improve the pathological conditions of insulin resistance, net of any results, about weight loss and fat.

Triglyceridemia and cholesterol

A ketogenic diet high in fat leads most people to have concerns regarding the effects on triglyceridemia,  cholesterolemia, What is keto diet  and the potential increased risk for cardiovascular disease. High levels of total cholesterol but above all high levels of  LDL  (the so-called bad cholesterol ) and low HDL (the so-called good cholesterol) correlate with an increased risk of disease.

Indeed, the first short-term studies showed a sharp increase in blood lipid levels following a high-fat diet. However, some subsequent research showed no relevant changes in blood parameters, and some even showed a decrease in cholesterol levels. Scientific research has therefore not brought conclusive results, and it is wrong to extrapolate conclusions starting from the analysis of only a part of the existing studies on the subject. But why is this research not reliable?

The problem is always the same: these are short-term studies, and therefore not only are they not predictive of anything, but they also tend to present variable conclusions. On the other hand, few long-term studies except those on epileptic children who have followed a ketogenic diet for 2-3 years. However, these subjects do not represent an adequate study model and cannot be used to reach absolute conclusions. However, in their case, the blood lipid levels rise (in fact, it is considered one of the side effects of a ketogenic diet observed over a long period). Such a diet is not meant to be sustained for life, and researchers say any changes in blood lipids can be corrected at the end of the diet.

Long term protective

In support of this thesis, the example of the Inuit often gives. These people follow a very low-carb, high-fat diet for long periods each year, and yet there is no evidence that they develop heart disease faster than other Americans. This suggests other long-term protective effects (albeit with all the appropriate limitations that such epidemiological studies have).

That said, some doctors are voicing their concerns about the rise in degenerative diseases that correlate with high blood lipid levels. However, these conditions take years or even decades to develop. Unless an individual observes an excessively hyperlipidemic diet for 10-15 years without interruption, researchers do not believe there can be any health problems.

Finally, another problem in assessing blood lipid levels lies in the fact that these are dependent on calorie restriction and, above all, on weight loss (however, we are talking about two related aspects). So, we can say that the position of scientific research on the subject is this:

1. If an individual loses weight / fat on low-gluTheir cholesterol levels will drop if / ketogenic diet, their cholesterol levels will drop.
2. If an indie following a ketogenic diet, their cholesterol levels will rise.

Clinical experience tells us that individuals on a hyperlipidemic hypoglycemic diet have a wide varying range of responses: some show a drastic decrease in cholesterol, others an increase. As for triglycerides, What is keto diet? Usually, with the ketogenic diet, there is a reduction in blood levels. This can be explained by the increased use of fatty acids in most tissues, such as skeletal muscle.

Since there is no absolute conclusion about cholesterol levels during such a diet, subjects should monitor blood lipid levels periodically.

Constipation: What is the keto diet

Another criticism made of ketogenic diets is their correlation with constipation. This disorder represents one of the most common side effects found in a diet of this type. Most likely, all of this derives from the low intake of daily dietary fiber: the lack of carbohydrates leads researchers to think that fiber intake is generally low or, in any case, much lower than in those What is keto diet who follow a more balanced low-calorie diet. There is no doubt that fiber is an essential “nutrient” for human health. At the base of this, it is always recommended to use a fiber supplement (sugar-free) to increase the total daily intake.

However, research seems to establish (but not in a specific and absolute way for now) that the added fibers are not as beneficial as the fibers found naturally in foods. My advice, sincerely dictated only by a little common sense, What is keto diet is to foresee the consumption of different portions of vegetables even if you follow a ketogenic diet as they are undoubtedly beneficial for the state of health and also do not contain large quantities of carbohydrates and hardly hinder the adaptation to ketosis.

What to eat on the ketogenic diet?

The foods of the ketogenic diet must be free or almost free of carbohydrates: for this reason, attention is paid to products such as meat, fish, eggs, nuts, oil.

Allowed foods

As for protein sources, What is the keto diet? There is no restriction whatsoever, although it is clear that a ketogenic diet will be unbalanced on animal rather than vegetable proteins since the latter often come from sources that are also rich in carbohydrates. Finally, ketogenic diets are high in fat, and the primary sources to consider are nuts, fish, extra virgin olive oil, and all sources of unsaturated and medium-chain fats. However, due to the enormous lipid intake expected, it is often necessary to compromise and accept to consume sources rich in saturated fats, which are also rich in proteins.

Prohibited foods: What is the keto diet

Are implicitly eliminated from the diet (or reduced to the bone) cereals, potatoes,   sugary fruit, and any food rich in carbohydrates. The low carbohydrate intake will be fully (or primarily) satisfied by the consumption of vegetables.

The ketogenic diet for weight loss

The basic argument never changes:  to lose weight and lose fat, you need a calorie deficit, therefore a low-calorie diet. What is keto diet Some characteristics attributed to the state of adaptation to ketosis have made the ketogenic diet more attractive than other low-calorie diets: suppressing appetite and well-being (absence of asthenia and a sense of exhaustion), conditions that people often suffer in an attempt to lose weight.  

In any case, at least as far as the feeling of satiety is concerned, this does not seem due to the state of ketosis as to the effect of proteins. Therefore, this advantage is not an exclusive feature of ketogenic drugs, somewhat of high-protein diets.

For some years now, some researchers have been suggesting that low-carb diets as a treatment for obesity have been based on the simple assumption that individuals tend to eat fewer calories  (and therefore lose more weight/fat) when carbohydrates are limited to a maximum of 30-50 grams per day or less. 

However, the ketogenic diet is not superior to other relatively high-protein, low-calorie diets in terms of fat loss. What is keto diet If anything, it may be better, in some cases, and on some subjects, for the appetite-suppressing effects induced by the high intake of proteins and fats that stimulate satiety more than sugars and for the effect of ketones (although this also is still discussed).

Over time, different approaches to this diet have been developed. Thus cyclical ketogenic diets were born, of which probably the most famous is still the metabolic diet.

Example of a ketogenic diet

Here is an example of a ketogenic diet with some common foods you can eat.

Breakfast: What is the keto diet?

Whole yogurt and milk

Eggs

Cheeses

Ham or bacon (not recommended)

Dried fruit

Smoked salmon

Lunch: What is the keto diet

Meat or fish

Cheese or eggs

Avocado  or olive

Fibrous vegetables (cauliflower, salad, fennel, zucchini, etc.)

Olive oil or butter

Dinner: What is the keto diet

Meat or fish

Cheese or eggs

Avocado or olives

Fibrous vegetables (cauliflower, salad, fennel, zucchini, etc.)

Olive oil or butter

Snacks: What is the keto diet

Dried fruit

Whole yogurt

It is always better to prefer monounsaturated fats and not to overdo it with red meat and animal fats. What is keto diet Even cheeses and their salt content should not exceed the recommended daily dose (3-5g). It is advisable to increase hydration by drinking 3-3.5dl for every 10kg of body weight.

Ketogenic diet scheme

Example 1 – 80 kg male training with weights

Phase 1 Set your total calorie intake	Calculate your TDEE – let’s both 2500 kcal
	Cut calories by 20-25% – 2500-600 = 1900 kcal
Phase 2 Set your protein intake	Multiply the weight in kg by 1.6-2.2 g / kg = 80 × 2 = 160 g
	160 g of protein equals 640 kcal
Phase 3 Set your carbohydrate intake	20g of carbohydrates = 80 kcal
	To take through vegetables
Phase 4 Set your fat intake	Subtract the kcal taken from proteins and carbohydrates from the total calorie
	1900 – 640 – 80 = approximately 1180 kcal
	1180 kcal / 9 = about 130 g of fat

 

So, the ketogenic diet of the person taken as an example will be as follows:

• Protein: 160 grams / day.
• Carbohydrates: 20 grams/day.
• Fat: 130 grams / day.

After the first three weeks of the diet, you increase the carbohydrate intake and reduce the protein intake slightly.

Example 2 – 65 kg woman training with weights

Phase 1 Set your total calorie intake	Calculate your TDEE – let’s both 1800 kcal
	Cut calories by 20-25% – 1800-400 = 1400 kcal
Phase 2 Set your protein intake	We set the protein at 130g because that’s the minimum allowed
	130 g of protein equals 520 kcal
Phase 3 Set your carbohydrate intake	20g of carbohydrates = 80 kcal
	To take through vegetables
Phase 4 Set your fat intake	Subtract the kcal taken from proteins and carbohydrates from the total calorie
	1400 – 520 – 80 = about 800 kcal
	800 kcal / 9 = about 90 g of fat

The ketogenic diet will therefore compose as follows:

• 130 proteins.
• 20 carbohydrates.
• 90 fat.

After three weeks. Dietary protein intake can lower. And fat or carbohydrate intake increased. To meet the determined calorie requirement.

Ketogenic diet in sport

During total fasting for glucose production. The degradation of proteins has led over the years to study. And experiment with two distinctly different approaches to avoid. Or at least reduce this loss. What is keto diet The most intuitive and most straightforward? The approach was to provide glucose to eliminate. The need to use proteins for energy purposes. However, this had a negative and intuitive side effect. The adaptation to ketosis did not occur or took place more slowly.

The second approach was based.  Keto diet recipes, however, on substantially different reasoning. Since in the absence of glucose. Before the body completely adapts to ketosis. A large part of the proteins use for energy purposes. With negative consequences on muscle mass. We solve the problem simply by increasing protein intake. In this way, the muscle mass will affect in a much lesser way.

This intuition does not even present the negative side of the first approach. It is true that proteins also raise insulin. What is keto diet But they do so in a slower way than carbohydrates which leads. To a consistent elevation of blood sugar. In addition, Proteins also stimulate glucagon. In this way, The conditions for establishing ketosis roughly maintain. (The level of proteins that can take before they affect ketosis. Processes are very high if the carbohydrate intake is minimal).

Studies and debates: What is keto diet

After much research. Studies and debates. It concludes that a  protein intake of about 1.5 – 1.75 g / kg. Of ideal body weight would be enough to save most of the nitrogen loss. (And therefore to reduce protein catabolism. muscle ). Especially once one has adapted to ketosis. Therefore, glucose requirements have significantly decreased. (About 30 grams for the brain alone compared to almost 100 grams per day in normal conditions).

Therefore, from this point of view. In any type, Therefore, from a ketogenic diet. Daily protein intake is essential to preserve most of the muscle mass. In general. Regardless of body weight. What is keto diet The minimum amount of protein that must consume during the first three weeks? A ketogenic diet would appear to be around  150 grams per day. As also indicated by Lyle McDonald. While after the first 3-4 weeks protein. Intake can also lower.

In conclusion, ketogenic diets can help maintain muscle mass if the protein intake is adequately correct. Still, in any case, there is no evidence that they are worse or better than other low-calorie diets with suitable protein intake.

Epilepsy and the ketogenic diet

A ketogenic diet is a therapeutic tool that increasingly uses. (I hope it will be more and more widespread. As there are still many pediatricians and neurologists. Who are not sufficiently updated in this sense) in drug-resistant epilepsies. According to a recent  Consensus. The ketogenic diet should consider after having ascertained. The ineffectiveness of the first two antiepileptic drugs used. Or even better. As an adjuvant to drug therapy.

It has now been established that during the developmental age. If correctly conducted. The ketogenic diet does not lead to subversions of the auxological trend. As it believes in the past (that is, What is keto diet the growth of children not compromise). From a strictly clinical point of view. The ketogenic diet appears to associate with a reduction in seizure frequency. More significant than 90% in 30% of patients treated. Independent of age. Type of seizure and etiology.

Conclusions on the ketogenic diet: pros and cons

In conclusion, The ketogenic diet does not show particular contraindications. But not even significant advantages compared to other high-protein diets. Satiety certainly a helpful factor to consider for those. What is keto diet Who wants to lose weight with a low-calorie diet. guarantee by the high protein intake and not by the ketogenic in itself. The potential cons of liver or kidney damage disprove. At least for now. By scientific research.