Keto Diet Dangers You Need to Know
How fats burn in the flames of carbohydrates on a low-carb keto diet, participate in the Krebs cycle, turn into ATP, and why ketone bodies are not life-threatening.
The keto diet, the strictest version of the LCHF (high-fat, low-carbohydrate) diet, is up to 20 grams of carbs per day. Most traditional nutritionists believe that following such a diet for a long time is impossible and even dangerous from a biochemical point of view. Their main arguments go like this:
- For the Krebs cycle, the sequence of chemical reactions that produce the most ATP molecules (the universal fuel our cells use), we need to eat more than 20 grams of carbohydrates a day.
- The body cannot use fats from food without carbohydrates-"fats burn in the flame of carbohydrates. To obtain energy from fats, the body must receive a certain amount of carbohydrates - usually, a figure exceeding 100 grams of carbohydrates per day is named. According to classical nutritionists, anything less than this figure will, at best, lead to a loss of strength, nervous breakdowns, and depression.
- At worst: ketone body poisoning and ketoacidosis, a life-threatening condition.
Figuring out how the body can eat ketones and why a person doesn't die from a lack of carbohydrates on a ketogenic diet?
What are ketones?
"Ketones" or "ketone bodies" are substances the body gets from fat and uses as an energy source on a low-carbohydrate diet.
In evolution, the human body has developed many different ways of obtaining energy from nutrients. And the fate of macronutrients (proteins, fats, and carbohydrates) can change depending on their abundance or lack of food. It is the availability of alternative pathways that allow the body to obtain the energy it needs under different conditions: physical exertion, hypoxia, starvation, lack of one or another macronutrient.
Anyone who remembers the basics of organic chemistry at school immediately thinks of a bottle of strong-smelling liquid labeled "acetone. So what, you have acetone in your body and can eat it?
On a proper diet, when the diet contains many carbohydrates, the content of ketone bodies in the blood is small (no more than 0.3 mmol/l), and the proportion of acetone among them is no more than 2%.
The remainder is beta-hydroxybutyrate and acetoacetate. It is these substances that can be used as an energy substrate. Acetone, on the other hand, is excreted unchanged in the urine.
On a high-fat, low-carbohydrate diet, the number of ketone bodies in the blood can be up to 6 mmol/l, acetone up to 0.05 mmol/l.
What is the Krebs cycle, and how do carbohydrates and fats participate in it?
The main result of catabolic processes is energy production. In our bodies, the universal energy source is ATP (adenosine triphosphate), formed due to many functions, such as glycolysis, oxidative decarboxylation of pyruvate, and the tricarboxylic acid cycle (Krebs cycle).
The latter allows the maximum amount of ATP to be obtained. With sufficient carbohydrate intake, acetyl-CoA, also formed from fat, enters the tricarboxylic acid cycle.
This cycle is a closed sequence of conversions of 10 tricarboxylic acids into each other, beginning with the addition of acetyl-CoA to oxaloacetic acid (oxaloacetate) to form citric acid (citrate) and ending with the conversion of malic acid (malate) to oxaloacetate. For this reason, there is a winged expression that "fats burn in the flame of carbohydrates.
When carbohydrates enter the body in small amounts, the workings of the Krebs cycle are altered. The body itself synthesizes glucose from oxaloacetate, making acetyl-CoA unable to enter the Krebs cycle.
And then, the processes of acetyl-CoA conversion into ketone bodies are activated, which are then used as "fuel."
Thus, if carbohydrates (glucose, fructose, etc.) enter the body in small amounts, ketones become energy substrates.
This macronutrient utilization pathway occurs in the ketogenic diet. Limiting carbohydrate intake (sugar, sweets, bread, baked goods, vegetables, fruits) causes fats (oils, whole fat products) to be metabolized through the ketogenic diet pathway.
Special mention should be made of protein intake. Unlike carbohydrates and fats, which can transform into each other, amino acids (the components of proteins) cannot be formed from other macronutrients.
Many amino acids can be broken down to form ketone bodies. But such utilization is a great luxury for the body because of the importance of amino acids in other processes.
Therefore, on a ketogenic diet, you need to ensure enough protein in the diet - 1 gram per kilogram of body weight.
At the same time, excess consumption of protein is harmful - excess amino acids, if the body can not use them for their intended purpose, can be converted into glucose by the mechanism of gluconeogenesis.
Can all organs consume ketone bodies as their primary fuel?
The question arises: is the body's consumption of ketone bodies and glucose equal? Yes, because the participation of acetyl-CoA in the Krebs cycle produces 24 molecules of adenosine triphosphate (ATP), while the breakdown of acetoacetate and beta-hydroxybutyrate produces 23 and 26 molecules of ATP, respectively.
Virtually the entire body can exist, getting energy only from ketone bodies. Moreover, ketone bodies are the preferred source of energy for the brain, muscles, and cortical layer of the kidneys.
Only one organ cannot consume ketone bodies - the liver, which does not have the necessary enzymes (although the ketone bodies themselves are formed in the liver). In the ketogenic diet, there is always a tiny number of carbohydrates in the diet. Calling a keto diet carbohydrate-free is fundamentally incorrect.
Do ketones poison the body?
There are several types of low-carbohydrate, high-fat (LCHF) diets: the classic ketogenic diet, the modified ketogenic diet, the modified Atkins diet, the moderate and liberal LCHF.
The classical ketogenic diet is used for severe neurological diseases (epilepsy, neurodegenerative syndromes, autism), endocrine diseases (type 2 diabetes, hypothyroidism), oncological diseases. In such situations, a strict calculation of meals, measurement of foods to grams, daily 2-3 times the size of blood ketones is required.
This is because a sharp increase in ketone bodies (more than seven mmol/l) can significantly deteriorate well-being, and blood acidification (ketoacidosis) accompanying excessive levels of ketone bodies can lead to severe consequences.
The classical ketogenic diet is administered only in the hospital under medical supervision for 10-14 days, followed by control of blood values at home.
Lighter versions of the diet, including the modified Atkins diet, do not require careful culinary calculation and are limited mainly to reducing the daily amount of carbohydrates to 20 grams with an increased fat intake.
There is no need to measure daily ketone body levels on these diets, as they rarely exceed 3-4 mmol/l.
Lightened keto diets can be practiced on their own as part of a healthy lifestyle.
Unlike strict options, with LCHF, it is possible to return to a traditional diet and then resume the diet without the risk of deterioration. There is no limit to the duration of the diet because even strict versions of the diet can keep patients for many years.