Is Keto Diet for Everyone?

Obesity and obesity-related diseases have become emerging issues in global health, and are associated with many underlying factors – genetic, social, psychological, hormonal, environmental (family obesity) and more. To illustrate its detrimental effects on the population, we just need to take a look at WHO statistics, which reveal that adult mortality (due to obesity) is approximately 4 million per year.

(Ironically, at the same time, in some other parts of the world, hundreds of millions of people are suffering from malnutrition and poor diet, the major factors for ill health and premature death).

Unlike some other conditions that require long-term and complex medical interventions, we can manage weight and obesity-related disorders, with adequate nutrition and natural therapies as a primary ‘cure’.

There is a wide spectrum of effective diet regimens that are, at the same time, a bit of good-standard health advice. Among numerous dietary guidelines and recommendations for losing weight, the keto diet has attracted lots of attention since 1920, when it was used as a dietary treatment for children with refractory epilepsy (medication-resistant epilepsy).

What is the ketogenic diet and how it works?

The original keto diet for treating epilepsy is a strict dietary regimen with high-fat (up to 90% of calories) and minimal carbohydrate intake (or, preferably, no carbs at all).

However, there are ‘milder’ types of the keto diet for weight loss, with better overall compliance, such as, for example, Atkins diet, its most common variety. What all of them have in common is a high intake of fat (and protein) and low intake of carbohydrates, which is usually less than 50 g per day.

The high consumption of fats in the ketogenic diet results in ketosis, which is a natural, physiological state of the organism when blood sugar levels are very low and the concentration of ketone bodies is high, which is also seen in intermittent fasting and type-1 and type-2 diabetes.

It is very important not to confuse ketosis with ketoacidosis. Namely, ketoacidosis is a pathological state of the organism (usually seen in type-1 and type-2 diabetes), when the level of circulating blood ketone concentration is very high (exceeding 20 moll/L), thus leading to a reduction in the pH in the blood. Unlike ketoacidosis, ketosis is a controlled metabolic process in which there is no drastic change in pH. Actually, pH remains 7,4. (2)

Glucose and ketones as an energy source

In the ketogenic diet, high consumption of fats and low intake of carbohydrates leads to la ow level of glucose in the body. Because glucose is the main source of energy for the brain, the organism needs to find other sources for energy supply. This is obtained via ketogenesis, i.e., synthesis of ketone bodies from acetyl coenzyme A. This coenzyme is the ultimate degradation product created by the breakdown of fatty acids in the liver cells, because this organ is the primary ketogenic source. The part of it enters the citric acid cycle and is oxidized to the end products of CO2 and H2O.

Under normal conditions, the brain uses glucose as an energy source. But, during periods of intermittent fasting and dieting, its cells develop the ability to use ketone bodies as the ‘fuel’. Ketone bodies – acetoacetate, β-hydroxybutyrate acid, and acetone – used by central nervous system (CNS) and other organs as an alternate energy source, provide even more energy than glucose. (2)

The keto diet for weight loss

Most mainstream nutritionists and scientists agree that a ketogenic diet (or more precisely their popular varieties) leads to significant weight loss. The disagreement is about the exact mechanism through which this is achieved. Possible biochemical pathways, they say, might be a reduction in lipogenesis (the process of fatty acid and triglyceride synthesis from glucose or other substrates), increased lipolysis (the process responsible for the catabolism of triacylglycerol), gluconeogenesis (the process by which the body produces glucose from non-carbohydrate precursors), and/or the thermic effect of proteins. (2)

Additionally, some researchers think that metabolic advantages of the keto diet, such as circulating levels of insulin, might trigger the weight loss process, while others do not share their enthusiasm for the idea.

However, a recent study suggests that ketosis can indeed suppress appetite due to the direct effect of ketone bodies and modifications in the level of some hormones. In comparison, study participants on the ketogenic diet (unlike those on non-keto), felt significantly less hungry.

The diuretic effect (water loss) of the ketogenic diet is also a contributing factor in losing weight. To prevent dehydration, an adequate amount of water (2l per day) is recommended. 

Type-2 diabetes and the keto diet

As mentioned before, increasing obesity and insulin resistance are the major risk factors for type-2 diabetes and cardiovascular disorders. Carbohydrate intolerance due to insulin resistance occurs when the body’s cells stop responding quickly and effectively to insulin signals (which regulates blood sugar concentration), following carbohydrate intake. Because our body cannot “allow” too much sugar in the blood, it is forced to release more insulin. Over time, the beta cells in the pancreas that synthesize insulin ‘wear-out’ and, consequently, type-2 diabetes develops.

What happens next is that our body can’t utilize the carbohydrates (mostly made from simple sugar) to produce energy.

Observational studies show that when the intake of carbohydrates is restricted, the signs and symptoms of insulin resistance are improved or even disappear. Although there is some risk of developing hypoglycemia (low blood glucose), the study showed that glycemia remains within the physiological level due to its formation from non-carbohydrate substrates (gluconeogenesis is more intense during the ketogenic diet). Along with glycemic, other biochemical parameters, such as hemoglobin A1c and insulin sensitivity, are also improved. (1) (2)

The ketogenic diet and cardiovascular disorders

It is important to understand the effects of the ketogenic diet on the total lipid profile. The results of the research presented (2) show a decrease in total cholesterol and triglycerides, and an increase in HDL (‘good cholesterol’). Also, the increase in the size of the LDL is also a beneficial factor (because smaller LDL particles are more atherogenic, i.e., bind more readily to the vessel wall and contribute to the formation of atherosclerotic plaque).

Additionally, the ketogenic diet is thought to directly lower the level of total cholesterol by inhibiting the enzyme necessary for the synthesis of endogenous cholesterol (cholesterol synthesis in our body). This enzyme is activated by insulin, and when there is not enough glucose in the circulation, there is no signal for insulin synthesis, and consequently, the enzyme is inhibited. This can potentially reduce cardiovascular risk. However, attention should be paid to the type of fat in the diet. (2)

Is the keto diet safe for everyone?

No, it is not. Contraindications and side effects of this extreme regimen can seriously affect your health, it is best to talk to your doctor before embarking on any type of diet! Some researchers argue that this diet can be useful for overweight individuals with metabolic syndrome, insulin resistance, and type-2 diabetes and other pathological conditions such as polycystic ovarian syndrome, acne, neurological diseases, and cancer. (2)

Contraindications

The ketogenic diet is contraindicated (which means that the diet should not be used in certain conditions) in patients with pancreatitis, liver failure, and disorders of fat metabolism: primary carnitine deficiency (the body’s inability to use fats) and carnitine palmitoyltransferase deficiency (the body’s inability to convert certain fats long-chain fatty acids into energy), carnitine translocase deficiency (genetic, life-threatening disorder in fatty acid oxidation), porphyria (skin and nervous system disorders) or pyruvate kinase deficiency (hereditary metabolic disorder). (1)  

Side effects

There are some adverse effects related to the ketogenic diet that should not be dismissed: constipation, headache, halitosis, muscle cramps, rash, and general weakness. Although this might sound a bit discouraging, it is important to know that those unpleasant sensations are transient and can be treated. Drinking appropriate amounts of water and taking supplements with magnesium and potassium (only if prescribed by the doctor) may help reduce these symptoms. Also, as the excretion of sodium is changed when the carbohydrate is restricted, adequate sodium intake is also recommended. (1) (2)

A smaller number of studies show significant complications due to dehydration, electrolyte disturbances, and hypoglycemia (low sugar blood level)(3). Severe hypoglycemia can be seen in patients with diabetes when medications are not adequately adjusted before starting the diet. (1)

However, its ‘milder’ varieties, based on (refined) low-carbohydrate intake, might be a useful tool to treat obesity and many other obesity-related disorders.

In the meantime, scientists and doctors continue to pieces together the patterns of the best diets and eating habits, nutritive components of foodstuff, and eating frequency, which would make us not only thinner and more attractive but also improve the quality of our lives.

By  S. Petrovic, MSc in Pharmacy

Edited by  editor@reteller.net

Acknowledgments:

1. Wajeed Masood; Kalyan R. Uppaluri. “Ketogenic Diet.” 

2. A Paoli, et al. “Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets.” Eur J Clin Nutr. 2013 Aug; 67(8): 789–796.

3. Yancy WS, Jr, Olsen MK, Guyton JR, Bakst RP, Westman EC. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial. Ann Intern Med. 2004;140(10):769–77.