Keto Diet

The keto diet has become very popular in recent years. There are many papers, articles, and texts written about it, but also plenty of disagreement among doctors, dietitians, athletes, and the general public. While some consider it a magic cure and an excellent way to lose unwanted weight, others find it dangerous to health, immunity, and mental performance.

If you came here looking for a quick answer, I am afraid there isn't one. Research indicates that the keto diet is highly effective if your only goal is rapid body fat loss, but it warns about insufficiently studied long-term health consequences, as well as the danger of the "yo-yo" effect. Additionally, experts emphasize the importance of a controlled transition from a ketogenic diet back to a normal one, along with the necessity of constant monitoring by a doctor or dietitian. There are high hopes for using this extreme dietary approach in treating and preventing various, primarily psychological, conditions such as childhood epilepsy. On the other hand, in cases of long-term chronic illnesses and disorders, such as diabetes or impaired liver function, it can lead to complications and adverse effects.

A Few Explanations Before Getting Started

Before breaking down the keto diet, it is essential to understand a couple of metabolic and energy processes in our body, primarily carbohydrate metabolism.

Carbohydrates are found in most foods people around the world consume daily, such as bread, rice, milk, pasta, potatoes, beans, and other fruits and vegetables. They represent the primary energy source for the functioning of the human organism and are the preferred fuel source utilized by the brain and muscles. Humans store a very limited supply of carbohydrates in the body in the form of glycogen, which is kept in the liver and drawn upon whenever needed. Additionally, the body is capable of producing carbohydrates on its own, but not in sufficient quantities to meet all of its metabolic demands.

During fasting or starvation, these reserves are quickly depleted, and the body transitions to an alternative energy source: fats. The amount of fat we can store, as well as its energy value, is much larger than the capacity and value of carbohydrates, which is why fats are considered the body's long-term energy vault.

However, the brain cannot feed directly on fatty acids, and during prolonged fasting, the body cannot produce enough carbohydrates to meet its needs. Because of this, the production of ketone bodies is triggered. Ketone bodies are molecules produced by the liver from stored fat reserves, which are rapidly burned during this process. When the body starts producing ketone bodies, they replace carbohydrates as the primary energy source, and the body is said to be in a state of ketosis.

What Is the Keto Diet?

The keto or ketogenic diet refers to a nutritional regimen that induces the production of ketone bodies in the organism. An insufficient intake of carbohydrates—less than 50g per day, which is less than the amount found in a single large potato—for 3 to 4 days triggers a physiological response similar to fasting. This results in the production of ketone bodies and accelerated fat utilization to meet the body's specific energy needs. A keto diet essentially covers any dietary plan that limits carbohydrate intake enough to achieve and maintain ketosis. Keto diets typically consist of a high fat intake, moderate protein intake, and a minimal amount of carbohydrates.

Types of Keto Diets

Due to differences in culture, religion, and financial means, multiple nutritional plans that induce ketosis have developed worldwide over the years. Variations in these plans include different ratios of carbohydrates, fats, and proteins, fluid restrictions, food group distributions, and allowed caloric limits.

Some of the most notable variants include:

Standard Ketogenic Diet (SKD) – a diet with a very low carbohydrate intake, making up less than 10% of daily energy needs. For comparison, official Dietary Guidelines for Americans recommend getting 45% to 65% of daily calories from carbohydrates. In addition, the standard keto diet derives more than 70% of its energy from fats and around 20% from proteins. In the past, it often included fasting as a preparation phase along with restricted calorie and fluid intake, but today most medical centers no longer enforce these strict measures.

Cyclic Ketogenic Diet (CKD) involves periods of low carbohydrate intake (under 15%), followed by periods of high carbohydrate refeeds (up to 70%). The idea is to maintain ketosis for a brief period, followed by a phase to replenish muscle glycogen and restore hormone levels. For example, 5 days of low-carbohydrate eating followed by 2 days of high-carbohydrate intake, so that one week constitutes a full cycle. It is worth noting that during the high-carb days, calorie intake should still remain moderate, especially if weight loss is the primary goal.

Targeted Ketogenic Diet (TKD) – is specifically tailored for individuals engaging in high-intensity physical training. It is highly similar to the standard ketogenic diet, but allows carbohydrate consumption around workout windows—mostly right before—so that they are immediately burned off during exercise.

High-Protein Ketogenic Diet – is designed for individuals looking to drop their body fat percentage while building or maintaining muscle mass. It is structurally similar to the standard version, but proteins are increased to cover about 35% of total energy needs. The carbohydrate ratio remains between 5% and 10%, while the rest of the daily requirements are covered by fats.

In the following sections, we will explore the positive, and then the negative effects of the keto diet on overall health. If you feel that the keto diet might be suitable for you, I strongly advise consulting with me or another trusted professional. This will help you minimize unnecessary risks and select the most appropriate dietary protocol for your specific body. The keto diet represents an extreme way of eating and should never be taken lightly.

Positive Effects of the Keto Diet

Obesity

A study published in 2020 examined the impact of the keto diet on body composition and strength in women. It concluded that the keto diet helps reduce body fat and maintain lean muscle mass when combined with resistance training. However, it proved ineffective for increasing overall muscle mass.

A systematic review of several studies investigated the long-term effects of low-fat versus low-sugar diets over a period exceeding one year. It showed that low-carbohydrate dietary interventions, like the keto diet, achieved significantly better weight loss results compared to low-fat setups. Individuals following the keto diet lost up to 4.5 kg within the first 2 weeks. It must be noted that the keto diet has a strong diuretic effect, so this large initial drop can often be attributed to water weight loss.

A 2014 study concluded that a ketogenic diet can assist in appetite control and boost oxidative pathways, thereby promoting reductions in body weight. The authors noted in their conclusion that when correctly implemented under expert supervision, the ketogenic diet can serve as a highly valuable tool for managing obesity.

Sugars

One of the indirect benefits of the keto diet is the naturally reduced consumption of refined sugars. The profound capacity of refined carbohydrates—like those found in sweets and white flour—to trigger negative health outcomes was overlooked for a long time. However, today we know that high consumption of refined sugars is linked to a 44% higher susceptibility to weight gain and metabolic syndrome, alongside a 26% increase in the risk of developing diabetes.

Epilepsy

The profound impact of the ketogenic diet on clinical nutrition has been known for over 100 years. This represents perhaps the most well-established medical application of this diet. There is a large volume of clinical data demonstrating highly consistent efficacy. Roughly 10% to 15% of children placed on a keto diet are completely seizure-free a year later, 30% experience a greater than 90% reduction in seizure frequency, while 40% to 50% find the diet either ineffective or too difficult to sustain and drop out within the first 6 months.

Blood Biomarkers

A cohort of participants prescribed a very low-carbohydrate diet achieved superior long-term results in reducing body weight, triglycerides, and diastolic blood pressure, while experiencing larger increases in both LDL and HDL cholesterol, compared to a group assigned to a standard low-fat diet.

Type 2 Diabetes

Adhering to a diet characterized by a very low carbohydrate intake leads to a reduction in blood glucose, lowered circulating insulin levels, and a decrease in insulin resistance. In diabetic patients, this can translate into a reduced dependence on medication. It is necessary to state that clinical experts are still actively debating the absolute long-term impacts of this diet on diabetic patients.

Negative Effects of the Keto Diet

In a 2018 Canadian publication, researchers reviewed a vast array of literature centered around ketogenic diets. They concluded that side effects are frequent and include: constipation (33%), bad breath (30%), muscle cramps (28%), headaches, diarrhea, general weakness, and skin rashes.

Due to these side effects, most ketogenic diet trials suffer from small sample sizes and high dropout rates during monitoring, which significantly limits the long-term validity of the findings. Additionally, for safety reasons, most clinical trials are not conducted for longer than 2 years, leaving open the question of what happens past this timeline.

Recent research indicates that this style of eating is not sustainable and should be discontinued after a few months up to a maximum of two years. This raises the possibility that despite the initial weight loss success, the desired outcomes may not stick long-term, causing patients to rapidly regain weight once they stop the diet. Independent of the diet's duration, transitioning from a ketogenic back to a normal diet must be structured, controlled, and gradual to prevent setbacks.

A critical issue with all low-carbohydrate approaches is the inadequate intake of fruits, vegetables, and whole grains. This restriction can lead to various vitamin and mineral deficiencies essential for proper bodily function. Correct supplementation can mitigate these negative effects.

Meat preparation can introduce another health issue. When meat is prepared at high temperatures, such as through frying or grilling, it forms advanced glycation end-products. When ingested, these compounds increase inflammation and oxidative stress within the body, leading to accelerated biological aging and a heightened vulnerability to age-related diseases.

Furthermore, some papers suggest that the positive impacts of the keto diet on conditions like epilepsy can be achieved through alternative, more diverse, and sustainable approaches, such as the Modified Atkins Diet.

Conclusion

To conclude, I would like to emphasize that moderation and caution are the absolute cornerstones of any diet meant to be practiced long-term. While ketogenic diets clearly assist in achieving rapid short-term goals and managing specific clinical conditions, they can lead to long-term health complications and rebound weight gain. Furthermore, the frequent discomforts often drive individuals to abandon the diet early. Instead of sudden shifts and adopting extreme dietary styles, I highly recommend balancing your macronutrients so that all essential food groups have a place on your plate, alongside consulting professionals before making major lifestyle changes. A diverse, balanced diet always has been—and will remain—the healthiest way to nourish your body.

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