What is The Ketogenic Diet?

The ketogenic diet, or keto diet for short, is a low-carb, high-fat diet that has gained popularity for its potential weight loss and health benefits. This diet encourages the body to enter a state of ketosis, which burns fat for energy rather than carbohydrates. Central to the ketogenic diet’s success is the careful selection of healthy oils and fats, which play a vital role in maintaining overall health and well-being.

The ketogenic diet is a nutrition plan that focuses on consuming a high proportion of healthy fats (70%-75%), moderate amounts of protein (20%-25%), and minimal carbohydrates (5%, max 20-30 grams). By drastically reducing carbohydrate intake and replacing it with fat, the body is forced to enter a metabolic state called ketosis. In this state, the body becomes highly efficient at burning fat for energy, leading to potential weight loss and other health benefits.

Importance of Oils in the Keto Diet

Healthy oils and fats are crucial components of the ketogenic diet. They provide the body with the necessary energy and nutrients while on this low-carb plan. Some of the key reasons for including healthy oils in the keto diet are:

  1. Energy source:

    Since the body relies on fat for energy without carbohydrates, consuming healthy oils ensures that the body has a consistent and stable fuel source.

  2. Nutrient absorption:

    Fat-soluble vitamins, such as vitamins A, D, E, and K, require fat for proper absorption. Consuming healthy oils helps the body absorb these essential nutrients effectively.

  3. Hormone production:

    Fats are essential building blocks for hormone production. Consuming healthy fats supports the production of hormones that regulate various bodily functions, such as metabolism, inflammation, and mood.

  4. Satiety:

    Healthy fats help promote a feeling of fullness, reducing hunger and the likelihood of overeating.

Choosing Healthy Oils for the Keto Diet

When selecting oils for the ketogenic diet, opting for high-quality, minimally processed options is essential. Some of the best choices include:

  1. Coconut oil:

    Rich in medium-chain triglycerides (MCTs), coconut oil is an excellent energy source on a keto diet. MCTs are easily absorbed and converted into ketones, which can help with ketosis.

  2. Olive oil:

    High in monounsaturated fats and antioxidants, olive oil is a staple of the ketogenic diet. Opt for extra-virgin olive oil, which is less processed and retains more beneficial properties.

  3. Avocado oil:

    Another excellent source of monounsaturated fats, avocado oil, has a high smoke point, making it suitable for cooking at higher temperatures.

  4. MCT oil:

    A concentrated source of medium-chain triglycerides, MCT oil, can be added to coffee, shakes, or salads to boost ketone production and support ketosis.

What was the ketogenic diet used for?

Fasting and other diets have been used to treat epilepsy since at least 500 BC. To mimic the metabolism of fasting, the ketogenic diet (KD) was introduced by modern physicians in the 1920s to treat epilepsy. The ketogenic diet was initially utilized to treat epilepsy first by Russell Wilder in 1921.

Additionally, he created the term “ketogenic diet.” The ketogenic diet experienced widespread usage as a therapeutic diet for treating childhood epilepsy for almost ten years until the development of antiepileptic drugs ended its appeal. The ketogenic diet is making a comeback as a quick weight-loss strategy, and this relatively new idea has proven to be highly successful—at least in the short term.

By the end of the twentieth century, this therapy was available in only a few pediatric hospitals. In the last 15 years, there has been an explosion in the use of KD and scientific interest in it.

The mechanism of action of the ketogenic diet appears to be based on a fundamental shift in brain metabolism from a glucose-based energy substrate to a ketone-based substrate. This change is in some way critical to the maintenance of the epilepsy seizure threshold.

The ketogenic diet favorably affects cerebral energetics, and increased cerebral energy reserves may be the most critical factor endowing ketotic brain tissue with increased seizure resistance. Whether these metabolic changes contribute to acute seizure protection is unclear; however, the ketone body acetone has an anticonvulsant effect and may play a role in seizure protection by diet.

The main idea of the ketogenic diet today

The ketogenic/keto diet is a low-carb, high-fat diet shown to help some people lose weight and improve specific other health markers.

“The keto diet is suitable for losing excess body fat without starving and improving type 2 diabetes or metabolic syndrome.”

The idea behind the diet is to put your body in a state of ketosis, where it burns fat for fuel instead of carbohydrates.

The Macros of Ketogenic Diet

ketogenic diet

On a classic ketogenic diet, the carbohydrate intake is typically limited to less than 50 grams per day, with most of the daily caloric intake coming from fat (70-75%) and protein (20-25%).

Foods to avoid and prefer on Ketogenic Diet

Foods high in carbohydrates, such as bread, pasta, and sugar, are avoided, while foods high in fat, such as avocados, nuts, eggs, fish-seafoods, and oils, are emphasized. And also there are beverages, too; water is a good choice on this diet, and coffee, tea, and some herbal tea are the other options.

“It’s important to note that the ketogenic diet should be supervised by healthcare professionals for diabetes patients who require insulin, in people being treated for high blood pressure, in people who are breastfeeding, and it should be approached cautiously, especially for people with existing health conditions. Before starting a ketogenic diet, it’s recommended to consult with a healthcare professional to ensure it’s safe and appropriate for you.

What does “Ketosis” means?

Ketosis is a metabolic state that occurs when the body doesn’t have enough carbohydrates to burn for energy. Instead, it begins to break down stored fat into molecules called ketones, which can be used for fuel. This process is what gives the ketogenic diet its name.

  • When you eat much fewer carbohydrates, your body burns fat for fuel.
  • This can put your body into a metabolic state called ketosis.
  • In this state, your liver converts fat into small energy molecules called ketones, which your brain and other organs can use for energy.
  • A keto diet often drastically lowers insulin levels, which can help you access your body’s fat stores for energy. Many studies show you can lose significant weight on the keto diet without counting calories. The keto diet can have other positive health effects, such as lowering blood sugar levels.

In a state of ketosis, the liver produces ketones from fat. The body uses them for energy instead of glucose, the primary energy source when carbohydrates are available.

This shift in energy source can lead to weight loss, improved insulin sensitivity, and other potential health benefits for people.”

It’s important to note that the level of ketosis can vary depending on factors such as carbohydrate intake, exercise, and individual metabolic differences.

Glucose is stored in the liver and released as needed for energy. However, when carbohydrate intake has been deficient for a day or two, these glucose stores are depleted. The liver can produce some glucose from amino acids, glycerol, and lactate through a process called gluconeogenesis, but not nearly enough to meet all the needs of the brain, which requires a constant fuel supply.

Fortunately, ketosis can provide you, especially your brain, with an alternative energy source.

Ketones, or ketone bodies, are made by the liver from the fat you eat and your body fat.

Test options for ketosis

ketogenic diet

ketogenic diet

You can test your ketone level like;

  • Fasting blood sugar and ketones
  • Before lunch
  • 1 hour / 2 hours after lunch
  • Before dinner
  • 1 hour / 2 hours after dinner

Timeline for ketosis guideline for your body

ketogenic diet

Possible mechanisms of the Ketogenic Diet weight loss effects on obesity:

  1. Reduction in appetite due to higher satiety effect of proteins, effects on appetite control hormones, and a possible direct appetite suppressant action of the ketone bodies
  2. Reduction in lipogenesis and increased lipolysis
  3. The decrease in the resting respiratory quotient highlights greater metabolic efficiency in consuming fats
  4. Increased metabolic costs of gluconeogenesis and the thermic effect of proteins

The Physiology of Ketosis is explained in detail in this clinical study by the Department of Biomedical Sciences, University of Padova.

Keto Flu          Ketogenic diet                                                                                            

Individuals who are addicted to carbohydrates may experience symptoms of the keto flu, as depicted in the picture, within the

 first 3-7 days of starting a ketogenic diet.


Ketogenic diet Evidence for health issues

Scientific Studies for obesity

Over the past few decades, several strategies for controlling obesity and overweight have been proposed. The first studies looked at the effects of diets that only included water and total fasting, either with or without proteins. Sadly, it was discovered that they were linked to adverse events, which caused these strategies to be abandoned.

Strangely, total fasting was effective and generally tolerated despite the radical approach. At that time, a clear link was established between protein-calorie malnutrition and increased morbidity and mortality among hospitalized patients.

Initial research suggests that VLCKD (Very Low Carbohydrate Diet) could revolutionize the treatment of type 2 diabetes as well. As a result, VLCKDs should be considered an excellent first step for patients with obesity or type 2 diabetes who have been appropriately selected and motivated. They should be administered as part of a multicomponent strategy and under close medical supervision.

An alternate theory holds that dietary elements significantly influence the hormonal reactions that lead to obesity and that specific types of carbohydrates can change the homeostatic mechanism that prevents weight loss. According to the carbohydrate-insulin model (CIM) of obesity, a high-carbohydrate, low-fat diet leads to postprandial hyperinsulinemia, which encourages fat deposition and lowers the levels of circulating metabolic fuels (glucose and lipids). This causes people to feel more peckish and slows their body’s overall metabolic rate.

According to this theory, overeating is not the leading cause of obesity but rather one of its effects. The most potent anabolic hormone, insulin, encourages glucose uptake into tissues, limits the release of fatty acids from adipose tissue, prevents the liver from producing ketones, and promotes fat deposition and glycogen deposition.

Dietary carbohydrates, which are diverse in their glycemic load (GL) and glycemic index (GI) (an indicator of how quickly blood glucose rises after intake), are the primary catalyst for insulin production (derived from carbohydrate amount and glycemic index). The latter is the most accurate predictor of blood glucose levels postprandial following CHO consumption. Since carbs are the primary source of glucose, cutting back on them may result in lower insulin needs, improved insulin sensitivity, and a drop in postprandial glycemia. Accordingly, LCD may benefit the treatment of metabolic disorders and the etiology of obesity.

In a systematic review of 13 RCTs of ketogenic versus low-fat diets (N = 1577, 61% women, BMI 30 to 43 kg/m2), those on ketogenic diets lost 0.9 kg more than those on low-fat diets at 12 to 24 months (statistically different).

A systematic review of 11 RCTs (N = 1369, 71% women, BMI 30 to 36 kg/m2) found at 6 to 24 months that the ketogenic diet group lost 2.2 kg more than the low-fat diet group (statistically different, but results were inconsistent). Higher-quality studies showed no difference.

The purpose of a meta-analysis was to investigate whether individuals assigned to a VLCKD (i.e., a diet containing no more than 50 g of carbohydrate per day) achieve better long-term body weight and cardiovascular risk factor management compared with individuals assigned to a conventional low-fat diet (LFD; i.e., an energy-reduced diet containing less than 30% energy from fat). Individuals who participate in VLCKD achieve more significant long-term weight loss than those who participate in LFD; therefore, VLCKD may be an alternative tool for obesity.

Ketogenic diet and diabetes

In today’s world, the prevalence of type 2 diabetes mellitus (T2DM) has reached epidemic proportions. Clinical studies have demonstrated that cutting out carbohydrates and losing weight can reduce hyperglycemia, obesity, and T2DM in people with T2DM, which is linked to obesity.

Insulin resistance is the main feature underlying type 2 diabetes (T2D). A key feature of insulin resistance is the impaired ability of muscle cells to take up circulating glucose. A person with insulin resistance directs a more significant proportion of dietary carbohydrates to the liver, where much of it is converted to fat (i.e., de novo lipogenesis) rather than being oxidized in skeletal muscle for energy, thereby functionally manifesting insulin resistance as ‘carbohydrate intolerance.” When dietary carbohydrate is restricted to a level below which it is not significantly converted to fat (a threshold that varies from person to person), the signs and symptoms of insulin resistance improve or often disappear altogether. Still, there is also a continuum in the general population that disrupts insulin action in cells to varying degrees, which can cause a wide range of signs and symptoms.

A study by Dr. Bruce R. Bistrian, Cancer Research Institute, Boston, reported Insulin withdrawal and significant weight loss within a few weeks in T2D patients fed a very low-calorie, low-carbohydrate diet. A study by Gumbiner, B, Department of Medicine, Monroe Community Hospital, Rochester, NY, provided obese T2D patients with two types of hypocaloric (650 kcal) diets for three weeks that were similar in protein content. However, one had a much lower carbohydrate content (24 versus 94 g/day). As expected, the lower carbohydrate diet resulted in significantly higher circulating ketone concentrations (∼3 mmol/l), closely associated with lower hepatic glucose production. Interestingly, there was a strong inverse correlation between circulating ketones and hepatic glucose production, suggesting that higher ketone levels are associated with more favorable effects on glycemic control in diabetic patients.

Recently, Guenther Boden, MD, Temple University Hospital, performed an inpatient study in obese T2D patients who received a low-carbohydrate diet for two weeks. Plasma glucose decreased from 7.5 to 6.3 mmol/l, hemoglobin A1c dropped from 7.3 to 6.8%, and insulin sensitivity improved dramatically (75%).

So individuals with metabolic syndrome, insulin resistance, and T2D (all diseases associated with carbohydrate intolerance) can expect both symptomatic and objective improvements in disease risk biomarkers when they follow a well-formulated, very-low-carbohydrate diet. Glucose control improves not only because less glucose is supplied but also because systemic insulin sensitivity improves.

Ketogenic diet on longevity and cancer

Another beneficial effect that has been postulated is related to longevity. Although available data are limited to animal models, a ketogenic diet has increased AMPK in mice and inhibited the mTOR/AKT pathway. A ketogenic diet also decreases the serum ratio of IGF/IGF-binding protein 3 in mice, with beneficial effects on metabolic syndrome and cancer risk.

The Ketogenic Diet’s advantages

  • İmprovement of insulin sensitivity
  • Therapeutic effects
  • Appetite reducing
  • Stabilizing cholesterol levels
  • Weighing lost
  • Managing DM, IR, epilepsy, etc.

Low-carb diets vs. Ketogenic diet

Low carbohydrate diets come in various forms, with the keto diet being a specific type that has unique characteristics. Optimal carb intake can vary based on insulin tolerance and activity level, but the following are the common carb limits:

  • Keto diet: Typically under 20g net carbs per day, although some may consume up to 25g or 30g net carbs
  • Low carb diet: Typically under 50g net carbs per day
  • Moderate low-carb diet: Typically under 100g net carbs per day

Some people choose to count carbs carefully, while others simply focus on eating foods that are low in carbs or suitable for the keto diet. By comparison, the Dietary Guidelines For Americans suggest a standard American diet should consist of between 225 and 325 grams of carbohydrates per day.

The main difference between these diets is the carbohydrate intake. In a low-carb diet, one usually consumes 50-150 grams of carbohydrates daily, while in the keto diet, the daily carbohydrate intake is limited to less than 50 grams.

Another critical difference is protein intake. In a low-carbohydrate diet, protein intake can be high, but protein intake should be moderate at about 20% of the total calories in a keto diet. This is because excessive protein intake can prevent ketosis.

When individuals with type 2 diabetes consume less CHO, their body weight decreases, and their glycemic control improves; this impact is more substantial when a deficient carbohydrate diet is followed (KD). However, LCD and KD might not be suitable for everyone. It’s essential to weigh the advantages of weight loss and better glycemic control against the potential increase in cardiovascular risk brought on by the unfavorable lipid profile seen with KD, especially in people with type 2 diabetes. Additionally, long-term adherence to low-CHO diets continues to be problematic.

It’s important to note that healthcare professionals should supervise the ketogenic diet for diabetes patients who require insulin, people being treated for high blood pressure, in people who are breastfeeding. It should be cautiously approached, especially for people with existing health conditions. Before starting a ketogenic diet, it’s recommended to consult with a healthcare professional to ensure it’s safe and appropriate for you.