Today, there are two main global problems in our world – diabetes and obesity – which affect a huge number of people, primarily in developed countries and in America in particular.
The main cause of both is food.
The standard diet of an average person today includes a large amount of proteins and carbohydrates, which is equally harmful to health, as it leads to the development of insensitivity to two important hormones: insulin and leptin. The result is excess weight, the development of inflammatory processes in the body, and a decrease in the protective functions of cells.
What to do?
There is only one solution: dietary correction. The ketogenic diet is one of the effective ways to normalize weight and improve health. It allows the body to enter a state of ketosis, where fats, rather than glucose, begin to be used as the primary source of energy.
In this article, we will discuss the benefits/ineffectiveness of the ketogenic diet for weight loss and body drying, the types of ketogenic diets, the categories of people for whom it is contraindicated, provide a list of foods that can be consumed on a ketogenic diet and those that must be excluded, as well as touch on some possible side effects and how dangerous they are to health.
Main thoughts:
Benefits of the Ketogenic Diet
The ketogenic diet involves almost complete exclusion of carbohydrates from the diet, moderate protein intake, and a large amount of healthy fats – these are the three key factors for achieving a state of ketosis.
The Ketogenic Diet is Beneficial for Weight Loss
The ketogenic diet is one of the most effective diets for weight loss, restructuring internal processes for efficient fat burning for energy. It is especially beneficial for those who are overweight.
In one experiment, scientists compared the effects of a low-carbohydrate ketogenic diet and a low-fat diet on weight loss in overweight individuals. After 24 weeks, the group on the ketogenic diet lost an average of 9.4 kg, while the low-fat diet group lost 4.8 kg 1, which is almost twice as much!
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Suppression of Inflammatory Processes in the Body
Our body derives energy from two basic components of food: carbohydrates and fats. In critical conditions (such as improper nutrition, cutting in bodybuilding, for example), proteins can also be used, but that is not the focus here.
What distinguishes these two sources of energy? One of the main and fundamental differences between fats and carbohydrates is that during their use for energy (burning), fewer active oxygen-containing byproducts are released, including free radicals. This means that reducing the amount of carbohydrates in the diet lowers the risk of developing chronic inflammatory processes in the body.
Reducing Cancer Risk and a Means of Fighting Cancer
This is one of the remarkable properties of the ketogenic diet.
Dr. Dominic D’Agostino explains the actions of the ketogenic diet in cancer as follows 31:
“All cells in our body use glucose as a primary source of energy, but they can also obtain it from fats. However, cancer cells lack flexibility and cannot use fats for energy. When the body enters a state of ketosis on a ketogenic diet, cancer cells starve to death.”
Increase in Muscle Mass
Scientists say that ketones, which are formed in the body when switching to a low-carbohydrate ketogenic diet, have a similar structure to BCAA amino acids, which means that such a diet can also be beneficial for gaining muscle mass 32.
How exactly?
Ketones preserve a greater amount of BCAA amino acids for building and maintaining muscle mass, performing their functions where possible in the body.
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Appetite Suppression
Hunger is the primary reason we eat. The more we eat, the more calories we consume, the more weight we gain. The ketogenic diet reduces the feeling of hunger, which is largely determined by carbohydrates.
You have probably noticed that if you eat something sweet, shortly after you want to eat again. Why?
The mechanism is as follows. Fast carbohydrates, firstly, are digested very quickly (hence the name), emptying the stomach. An empty stomach starts pressing the “I’m hungry!” button.
Secondly, when a portion of fast carbohydrates (cakes, candies, cookies) in the form of glucose enters the blood, it triggers the release of insulin, whose job is to control blood glucose levels. The action of insulin leads to a sharp decrease in blood glucose concentration, which also “turns on” the feeling of hunger.
What happens on a ketogenic diet: because the amount of carbohydrates is reduced to a very low value, both of the above mechanisms for the onset of hunger stop working.
Reduction of Insulin Levels
As mentioned above, the entry of a portion of carbohydrates into the blood causes the release of insulin. If we regularly feed the body fast carbohydrates, insulin resistance can develop – type 2 diabetes.
Switching to a ketogenic diet or implementing its main principle – reducing the amount of carbohydrates in the diet – helps significantly reduce the risk of developing type 2 diabetes.
According to scientific studies, diabetics who switch to a ketogenic diet become significantly less dependent on medications and can actually restore insulin sensitivity 3.
The ketogenic diet is effective for weight loss, fighting cancer and diabetes, reduces chronic inflammatory processes in the body, normalizes insulin levels, and is even beneficial for gaining muscle mass.
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Types of Ketogenic Diet
There are several varieties of the ketogenic diet:
1 Standard Ketogenic Diet (for Everyone)
Recommended for most people (both healthy individuals and those suffering from obesity or diabetes) due to its effectiveness. Its main principle is that 70% of daily calories should come from healthy fats, 25% from protein, and only 5% from carbohydrates 5.
It is important to understand that on a ketogenic diet, fats are the food component that meets energy needs. Therefore, individual energy requirements (depending on the level of physical activity) should be met primarily through fats.
To achieve the effects of a ketogenic diet, it is crucial that the majority of calories come from fats, while the amounts of protein and carbohydrates are limited 6.
The main principle of the ketogenic diet is that the majority of calories should come from fats (~70%) and limited amounts from protein (~25%) and carbohydrates (~5%)
2 Targeted Ketogenic Diet (for Fitness)
This type of ketogenic diet is designed for those who are into fitness.
In this approach, the entire daily allowance of calories from carbohydrates is consumed in one meal 30-60 minutes before training.
The idea is to effectively utilize the energy provided by carbohydrates during the workout without hindering the action of ketones 7.
3 Cyclical Ketogenic Diet (for Professional Athletes)
The cyclical ketogenic diet is intended for professional athletes and bodybuilders. It alternates between a standard ketogenic diet and a high-carbohydrate diet, known in bodybuilding as “carb loading.”
Carb loading in bodybuilding is used to replenish glycogen in the muscles after strength training 10. Glycogen is a source of energy for muscles; it also makes them fuller as it binds water, increasing the volume of muscle cells.
The cycle is carried out as follows: 5 days of a standard ketogenic diet, followed by two days of carb loading. During the ketogenic phase, the carbohydrate intake is about 50 grams, while in the loading phase, it is 450-600 grams.
This type of ketogenic diet is not recommended for those with low levels of physical activity 11.
The cyclical ketogenic diet for professional athletes and bodybuilders involves alternating between a standard ketogenic diet (5 days a week, ~50 g of carbohydrates) and carb loading (2 days a week, ~500 g of carbohydrates)
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4 High-protein ketogenic diet (for weight loss)
This is a variation of the standard ketogenic diet: the amount of protein is increased by 10%, while the share of healthy fats is reduced by 10%.
What this provides: protein is beneficial for weight loss because it provides a greater feeling of satiety, reduces hunger, and has a thermogenic effect (more energy is required for its digestion).
Scientific studies confirm the effectiveness of the high-protein ketogenic diet for weight loss 12.
5 Restricted ketogenic diet (for fighting cancer)
At the beginning, we noted that the ketogenic diet is an effective weapon against cancer. This primarily concerns the restricted ketogenic diet.
When the amount of carbohydrates in the diet and the total calorie intake are limited, glycogen stores (which store excess carbohydrates for delayed use for energy) are gradually depleted, and ketones become the main source of energy for healthy cells. Cancer cells cannot use ketones for energy, which leads to their death 13.
One of the indicative scientific experiments confirming this fact. In 2010, a 65-year-old woman suffering from an aggressive form of brain cancer was advised to switch to a restricted ketogenic diet. Initially, she fasted, drinking only water, and then consumed only 600 calories a day. After two months, her weight significantly decreased, and the level of ketones in her body increased. Moreover, brain imaging using magnetic resonance and tomography showed no presence of a tumor in the brain 14.
The restricted ketogenic diet is effective in fighting cancer. This is explained by the inability of cancer cells to use fats for energy.
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Ketogenic diet during “cutting” in bodybuilding
As for the benefits of the ketogenic diet for cutting, there are too many “buts”.
The biggest of them lies in the contradiction of the fundamental principle of this diet – the almost complete exclusion of carbohydrates – to the goals of the cutting diet, which can only be achieved with the help of carbohydrates.
Carbohydrates during cutting:
- preserve muscle mass from catabolism by supplying energy to the muscles;
- preserve muscle mass from catabolism by preventing the use of amino acids (the building blocks of muscle tissue) for energy;
- stimulate the secretion of one of the most anabolic hormones – insulin;
- carbohydrates in the form of glycogen make muscle cells fuller, increasing their volume, which is an important factor in muscle synthesis, as well as increasing the size of muscles overall;
- ensure the maintenance of the training regimen, which is important for preserving muscle mass.
The importance of carbohydrates and the dangers of a ketogenic diet during body cutting are discussed in detail in the article Diet and Nutrition Program for Body Cutting by Natural Bodybuilder Layne Norton.
Prohibited Foods on a Ketogenic Diet
Before we look at the foods that can be consumed on a ketogenic diet, let’s take a close look at what is currently on our table and what should be definitely excluded.
The prohibited list of foods on a ketogenic diet primarily includes unhealthy, unnatural products, while the allowed list consists of whole, natural foods.
List of prohibited foods on a ketogenic diet:
- sugar;
- starch;
- packaged, processed, refined products (most of what is produced by humans);
- milk: milk contains carbohydrates in the form of lactose; one cup of milk is approximately the daily norm of carbohydrates;
- hydrogenated vegetable oils;
- soy products;
- soda.
Some of the listed products do not contain carbohydrates, but they are simply not healthy or beneficial.
The list of prohibited foods on a ketogenic diet mainly includes unhealthy, unnatural products produced by humans; the list of allowed foods consists of whole, natural products rich in healthy fats.
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Ideal Foods on a Ketogenic Diet
The list of allowed foods on a ketogenic diet includes whole, natural products that adhere to the fundamental principle: almost complete exclusion of carbohydrates, restriction of protein (~1 g per kg of body weight), and a sufficiently large amount of healthy fats.
List of foods allowed on a ketogenic diet that are rich in healthy fats:
- coconut oil;
- animal fats containing omega-3 (salmon, sardines, anchovies, and krill);
- olives and olive oil (check to ensure that the olive oil is not diluted with cheap vegetable oils);
- butter;
- raw nuts (almonds, cashews, hazelnuts, Brazil nuts);
- seeds (sesame, pumpkin seeds, caraway, hemp, flax);
- avocado;
- meat;
- raw cocoa butter;
- organic pasteurized eggs.
Vegetables
When building a menu on a ketogenic diet, it is important to include a large amount of green leafy vegetables, as they are rich in fiber, antioxidants, vitamins, minerals, and phytonutrients (broccoli, spinach, parsley, Brussels sprouts).
Fruits
As for fruits, while they are generally natural and healthy products, on a ketogenic diet most of them need to be excluded, as they contain a high amount of carbohydrates.
You can include a moderate amount of certain berries (blackberries, blueberries, cranberries) in the menu, as they are rich in antioxidants that are beneficial for health.
Beverages
It is essential to consume water. The following are also allowed:
- black coffee (without sweeteners and milk/cream), as it is rich in antioxidants;
- coconut milk;
- herbal teas (which contain antioxidants).
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Who Should Avoid the Ketogenic Diet
It can be confidently said that the ketogenic diet is beneficial for the overwhelming majority of us. But not for everyone.
Pregnant Women
During pregnancy, the need for nutrients significantly increases. Any diets (= nutrient restrictions), including the ketogenic diet, at this stage of life can have negative consequences for both the mother and the child 18.
Breastfeeding
During breastfeeding, carbohydrates are necessary for the mother to produce milk.
Professional Athletes
We mentioned earlier that the cyclical ketogenic diet was specifically designed for professional athletes. However, it is important to keep the following in mind.
The ketones produced in the body on a ketogenic diet can be a truly effective source of energy even for professional athletes, but it takes time (about 4-6 weeks) to reach a state of ketosis. Until that point, energy depletion is unavoidable, as the body has not yet adapted to the new type of nutrition. This can affect athletic performance and results.
Plan your transition to a ketogenic diet in advance to avoid losing shape when you need to show results.
Those with a Removed Gallbladder
The gallbladder contains a concentrate of bile (acids) secreted by the liver, which is necessary for digesting fats. Without it, the fats that form the basis of the ketogenic diet will not be effectively absorbed, leading to a deficiency of calories and nutrients.
Kidney stones (now or in the past)
If you have previously had kidney stones, there is a chance that the ketogenic diet may provoke their formation again. The reason is that ketones stimulate the excretion of uric acid, which is known to be a factor in the formation of kidney stones.
On the other hand, the risk of kidney stone formation on a ketogenic diet can be reduced by consuming enough leafy green vegetables that contain potassium and foods rich in healthy fats, such as avocados, for example. It is also very important to drink enough water.
Adolescence, when the body is still growing
Scientific data confirm that the ketogenic diet can be beneficial for treating certain medical conditions in children (for example, epilepsy 19). However, prolonged nutrient restriction can have a negative impact on growth 20.
The reason is that the ketogenic diet reduces the secretion of insulin-like growth factor (IGF-1) – a hormone that plays an important role in the formation of bones and muscles in children and adolescents.
Lean body type
Those who naturally have a lean body type (body mass index less than 20) should also avoid the ketogenic diet, as it may provoke even greater weight loss, which would be harmful rather than beneficial to health.
Anorexia
Anorexics on a ketogenic diet can die very quickly, as they already restrict their caloric intake for fear of gaining weight, and fats – the basis of the ketogenic diet – are their number one enemy.
Is the ketogenic diet useful for treating anorexia? Possibly. But it must be done under the supervision of a doctor and psychiatrist.
The ketogenic diet is contraindicated for: pregnant and breastfeeding women, professional athletes during competitions, those who have had their gallbladder removed or have kidney stones, adolescents during periods of rapid growth, lean individuals, and anorexics.
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Possible side effects of the ketogenic diet
The ketogenic diet has countless health benefits for most people. However, like any intervention in the usual diet, it can have some unpleasant side effects.
Side effects of the ketogenic diet:
Unpleasant breath
The reason for this effect is acetone – one of the types of ketones produced during ketosis in the body. It is excreted in urine and partially through the lungs with exhaled air.
The smell is unpleasant, but on the other hand, it is a sign that the ketogenic diet is working 2. You can get rid of it by brushing your teeth or using mouthwash.
Feeling of fatigue
At the very beginning of the ketogenic diet, you may experience a feeling of fatigue. This is the most common reason why many people stop following it, without reaching the point where the benefits of ketosis begin to manifest 23.
The reason for fatigue is the transitional period of the body adapting to using fats as the primary source of energy instead of carbohydrates. The adaptation process does not happen overnight and can take about 30 days 24.
Frequent urination
Excluding carbohydrates from the diet on a ketogenic diet leads to the depletion of glycogen stores in the muscles and liver, which is accompanied by the excretion of water that glycogen binds. During the first few days after starting the ketogenic diet, this can lead to frequent trips to the bathroom.
With the drop in blood insulin levels, excess sodium may also be excreted in urine 25.
Digestive issues
Any drastic changes in diet can lead to digestive problems. The ketogenic diet is no exception.
Constipation is one of the most common complaints among those transitioning to a ketogenic diet. Typically, they resolve after a few weeks once the body adjusts to healthy food 26.
Strong cravings for sweets
Strong cravings to eat something sweet are a natural consequence of deviating from a beloved habit, as well as switching to using fats for energy.
Do not succumb to the false sense of hunger for sweets: it will be very strong only at the very beginning of the transition to the ketogenic diet.
Hair loss
Do not panic if you notice more hair falling out on your brush at the beginning of following the ketogenic diet. This is most likely a result of drastic changes in diet, which is a stress for the body. As you adapt to the diet, this side effect should disappear 28.
Overall, learn to listen to your body. Any oddities that happen to you are signs sent to you to pay attention to them. Some indicate that something is wrong, while others are the consequences of breaking established bad habits.
Possible side effects when transitioning to a ketogenic diet are a result of drastic changes in nutrition, and all of them should pass over time. Among them are: bad breath, frequent urination, fatigue, constipation, strong cravings for sweets, and hair loss.
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Frequently Asked Questions about the Ketogenic Diet
– How to start a ketogenic diet?
To put your body into a state of ketosis, first review everything you are currently eating. Be sure to eliminate sweets, sugary drinks, and processed/refined/human-made foods.
The next step is to include whole, natural foods rich in healthy fats, containing a moderate amount of protein and minimal carbohydrates in your diet.
– How long does it take to achieve a state of ketosis?
Each person reacts differently to the ketogenic diet. During the first few weeks, you may experience some side effects of the ketogenic diet, such as constipation, fatigue, and frequent urination. As you adapt to the diet, you will start to feel better. On average, the adaptation period lasts about 30 days.
– How many carbohydrates can be consumed on a ketogenic diet?
For a standard ketogenic diet, the caloric intake from carbohydrates should not exceed 5% of the total caloric intake. For athletes, this value can be higher without negatively affecting the state of ketosis; they are recommended to follow a targeted ketogenic diet or a cyclical one.
– When will the positive effects of the ketogenic diet start to manifest?
The positive effects of the ketogenic diet can be felt as early as after the first week, when the body begins to release glycogen and the associated water, but the reduction in body fat will be minimal 29. Over time, more excess fat will gradually be lost, provided that the diet is followed.
