Keto Diet: Does It Work? Expert Reviews And Insights

The ketogenic or keto diet is a low-carbohydrate, fat-rich eating plan that has been used for centuries to treat specific medical conditions. In the 19th century, the ketogenic diet was commonly used to help control diabetes. In 1920, it was introduced as an effective treatment for epilepsy in children who did not respond to medication. The keto diet has also been tested and used in closely monitored settings for cancer, diabetes, polycystic ovary syndrome, and Alzheimer's disease.

The keto diet is gaining popularity as a potential weight-loss strategy due to the low-carb diet craze, which started in the 1970s with the Atkins diet. Today, other low-carb diets, including the Paleo, South Beach, and Dukan diets, are all high in protein but moderate in fat. In contrast, the ketogenic diet is distinctive for its exceptionally high-fat content, typically 70% to 80%, though with only a moderate intake of protein.

The premise of the ketogenic diet for weight loss is that depriving the body of glucose, the main source of energy, leads to the production of an alternative fuel called ketones from stored fat. The brain demands a steady supply of glucose, about 120 grams daily, because it cannot store glucose. During fasting or when very few carbohydrates are eaten, the body first pulls stored glucose from the liver and temporarily breaks down muscle to release glucose. If this continues for 3-4 days and stored glucose is fully depleted, blood levels of insulin decrease, and the body begins to use fat as its primary fuel. The liver produces ketone bodies from fat, which can be used in the absence of glucose.

When ketone bodies accumulate in the blood, this is called ketosis. Healthy individuals naturally experience mild ketosis during periods of fasting (e.g., sleeping overnight) and very strenuous exercise. Proponents of the ketogenic diet state that if the diet is carefully followed, blood levels of ketones should not reach a harmful level, as the brain will use ketones for fuel, and healthy individuals will typically produce enough insulin to prevent excessive ketones from forming.

However, critics argue that the keto diet is an unhealthy and potentially dangerous way to lose weight. Some experts warn that the keto diet can lead to muscle loss, fatigue, and even starvation mode, making weight loss more difficult. There are also concerns about the long-term effects of the keto diet on heart health, nutritional deficiencies, and overall sustainability.

While the keto diet may lead to rapid weight loss, it is important to consider the potential risks and consult a healthcare professional before starting any new diet.

Weight loss

The keto diet is a low-carb, high-fat diet that has been used for centuries to treat specific medical conditions. In the 1920s, it was introduced as a treatment for epilepsy in children. Today, it is gaining popularity as a potential weight-loss strategy.

How it Works

The keto diet forces your body to use a different type of fuel. Instead of providing your body with glucose from carbohydrates, the keto diet relies on the liver to break down stored fat into molecules called ketones. This process is called ketogenesis, where the term "keto" comes from.

To begin using stored fat as fuel, most people need to limit their daily carbohydrate intake to fewer than 20 to 50 grams, depending on body size. This is a highly individualized process, and some people may need a more restricted diet to produce enough ketones. Typically, it takes two to four days to reach a state of ketosis, when fat becomes the main source of energy.

There is evidence that keto diets can help with weight loss. They may help you lose fat, preserve muscle mass, and improve markers of disease. Some studies suggest that a keto diet may be more effective than a low-fat diet for weight loss, even when total calorie intake is matched.

For example, in one older study, people on a keto diet lost 2.2 times more weight than those on a low-calorie, low-fat diet. Triglyceride and HDL (good) cholesterol levels also improved. Another 2007 study found that the low-carb group lost three times more weight than the low-fat group over three months.

Keto diets may also lead to reductions in appetite and food intake. This is important when applying the research to a real-life setting, as it means you can eliminate certain foods and not have to track calories.

Long-Term Weight Loss

While the keto diet has been shown to be effective for short-term weight loss, there is limited research on its long-term effects. Some experts note that while the keto diet may lead to weight loss initially, the loss is unlikely to continue, and it can be hard to follow the diet long-term.

A 2019 review of low-carb diets found that the weight loss effect becomes similar to other dietary approaches after one year. This may be due to the restrictive nature of the diet, which can be challenging to maintain, as well as potential side effects and higher costs.

Who Should Avoid the Keto Diet

The keto diet may not be suitable for everyone. It is not recommended for people with certain medical conditions, such as disorders of fat metabolism, carnitine deficiency, or pyruvate kinase deficiency.

Additionally, the keto diet can be difficult to stick to due to restrictive food choices and potential side effects like "keto flu," which can include poor energy, increased hunger, sleep issues, nausea, digestive discomfort, and poor exercise performance.

It is always recommended to consult a doctor or dietitian before starting any new diet, especially if you have medical issues or take medication.

Alternatives to the Keto Diet

There are alternative ways to lose weight that may be more sustainable and healthier in the long run. These include:

• Checking portion sizes and making small decreases, along with increasing vegetable intake.
• Cooking from scratch at home and expanding your knowledge of fresh ingredients.
• Following a Mediterranean-style diet, which includes plenty of fish, nuts, seeds, healthy fats, and vegetables.
• Addressing the reasons why you eat, such as stress or poor sleep, rather than focusing solely on what you eat.

The keto diet can be an effective tool for short-term weight loss, but it may not be sustainable or suitable for everyone. It is important to consult a healthcare professional before starting any new diet, especially if you have medical issues or take medication. There are alternative approaches to weight loss that may be more suitable and healthier in the long run.

Energy levels

The keto diet can have a significant impact on energy levels, with some people reporting increased energy and focus, while others experience fatigue and tiredness.

Initial Energy Levels

When starting a keto diet, it is common to experience a period of adjustment as the body transitions from burning carbohydrates to burning fat for energy. This can result in initial fatigue and decreased energy levels. The duration of this transition period can vary, lasting anywhere from a few days to several weeks. During this time, it is recommended to take it easy and reduce physical and mental activities.

Long-Term Energy Levels

Once the body has adapted to the keto diet, many people report increased energy levels and improved focus. This is because ketones, the byproduct of burning fat, are an extremely potent fuel source for the brain. Additionally, eliminating carbohydrates helps to control and stabilize blood sugar levels, further enhancing focus and brain function.

Factors Affecting Energy Levels

There are several factors that can influence energy levels on a keto diet:

• Gender: Female hormone cycles can affect energy levels, with higher estrogen levels leading to increased energy and lower estrogen levels causing a dip in energy.
• Diet Composition: Ensuring adequate intake of healthy fats and moderate protein is crucial for maintaining energy levels. Consuming too much protein can spike insulin levels and slow down the transition to ketosis.
• Supplements: Taking supplements such as MCT oil, exogenous ketones, or caffeine can help boost energy levels and enhance the effects of the keto diet.
• Individual Differences: The impact of the keto diet on energy levels can vary from person to person. Some people may experience more pronounced changes in energy levels during the transition period.

Health risks

The keto diet is a low-carb, high-fat diet that has gained popularity in recent years as a weight-loss strategy. While it may be effective for short-term weight loss, it also comes with several health risks and side effects. Here are some of the potential health risks associated with the keto diet:

• Dehydration and Gastrointestinal Issues: The keto diet can cause water loss before fat loss, leading to dehydration. It is also associated with common gastrointestinal problems like constipation, diarrhea, nausea, and vomiting.
• Kidney Stones and Kidney Disease: The keto diet's focus on animal-based and high-fat foods can lead to an increased risk of kidney stones and long-term kidney damage, especially in those with existing kidney disease.
• Nutrient and Vitamin Deficiencies: The restriction of many fruits, vegetables, and grains in the keto diet can lead to deficiencies in micronutrients, including selenium, magnesium, phosphorus, and vitamins B and C.
• Liver Problems: The high-fat content of the keto diet can put a strain on the liver, potentially worsening existing liver conditions.
• Heart Disease: The keto diet's emphasis on saturated fats can lead to increased levels of "bad" LDL cholesterol, which is a risk factor for heart disease.
• Ketoacidosis: Ketosis, the metabolic state aimed for on the keto diet, is a mild form of ketoacidosis. While ketosis itself may not be harmful, ketoacidosis is dangerous and can be fatal if left untreated.
• Other Health Risks: The keto diet may also lead to fuzzy thinking, mood swings, reduced athletic performance, and social isolation or disordered eating due to its restrictive nature. It is not recommended for those with certain pre-existing conditions, such as eating disorders, liver or thyroid problems, or diabetes without proper medical supervision.

Long-term effects

The long-term effects of the keto diet are still unclear, and there is limited research on its safety and efficacy. However, here is a summary of the potential long-term effects:

Weight Loss and Regain:

The keto diet can lead to rapid weight loss, but this may be due to the release of stored water and muscle loss. Most people regain weight after stopping the diet, and the type of weight gained back is predominantly fat, which affects metabolism and makes future weight loss more difficult.

Nutritional Deficiencies:

The keto diet restricts fruits, vegetables, whole grains, and legumes, which are good sources of fiber and essential vitamins and minerals. This can lead to nutritional deficiencies, including fiber deficiency, which is crucial for gut health and has broader implications for overall health.

Athletic Performance:

Some research suggests that keto may negatively impact athletic performance due to the body being in a more acidic state when in ketosis. This could limit the body's ability to perform at peak levels, despite the weight loss that may be beneficial for speed and endurance.

Blood Vessels:

A "cheat day" on the keto diet, which includes a high-sugar treat, can have long-term consequences for blood vessels. This is because a sudden blast of glucose while on a high-fat, low-carb diet can damage blood vessels, according to researchers from the University of British Columbia.

Heart Health:

There are concerns about the long-term effects of a keto diet on heart health. Studies suggest that people on low-carb diets are more likely to develop atrial fibrillation (AFib), which increases the risk of blood clots, stroke, and heart failure. Additionally, a long-term diet high in saturated fat, which is common on keto, can increase unhealthy cholesterol levels (LDL), further elevating the risk of heart disease.

Cancer and Overall Mortality:

Research has found an association between low-carb, high-fat diets and an increased risk of dying from cancer and all other causes. Additionally, a study found that low-carb dieters who consumed large amounts of meat and dairy had a higher risk of early death compared to those consuming moderate amounts of carbs or plant-based protein.

In conclusion, while the keto diet may lead to rapid weight loss in the short term, there are potential long-term health risks. These include nutritional deficiencies, negative impacts on athletic performance and heart health, and increased risk of cancer and overall mortality. More research is needed to fully understand the long-term effects of this restrictive diet.

Nutritional concerns

The keto diet is a low-carb, high-fat diet that shares similarities with the Atkins and low-carb diets. It involves drastically reducing carbohydrate intake and replacing it with fat. The keto diet is extremely strict and difficult to maintain. To achieve ketosis, the diet requires 75% of calories to come from fat, 5% from carbohydrates, and 15% from protein.

High saturated fat content

The keto diet is associated with an increase in "bad" LDL cholesterol, which is linked to heart disease. McManus recommends keeping saturated fats to no more than 7% of daily calories. The diet also encourages the consumption of saturated fats from oils (palm and coconut), lard, butter, and cocoa butter.

Nutrient deficiencies

The keto diet restricts fruits, vegetables, and grains, which may lead to deficiencies in micronutrients such as selenium, magnesium, phosphorus, and vitamins B and C.

Liver problems

The high-fat content of the keto diet may put additional strain on the liver, potentially worsening existing liver conditions.

Kidney problems

The kidneys help metabolize protein, and the high protein content of the keto diet may overload them.

Constipation

The keto diet is low in fibrous foods like grains and legumes, which can lead to constipation.

Fuzzy thinking and mood swings

The brain functions optimally when it uses sugar from healthy carbohydrates as its energy source. Low-carb diets may cause confusion and irritability.

Weight regain

Critics of the keto diet argue that it is not a sustainable way to lose weight. Clinical reviews suggest that patients on low-carbohydrate diets tend to regain some of the lost weight within a year.

Social isolation and disordered eating

Strict diets like keto could lead to social isolation and disordered eating patterns.

Not suitable for everyone

The keto diet is not recommended for individuals with certain conditions, including those involving the pancreas, liver, thyroid, or gallbladder. It is also not advised for pregnant or breastfeeding women and those with eating disorders.

Side effects ("keto flu")

Adopting the keto diet can lead to side effects commonly referred to as the "keto flu," including fatigue, mental fogginess, irritability, upset stomach, dizziness, decreased energy, and mood swings. These symptoms typically occur during the initial phase of the diet as the body adjusts to using ketones as its primary fuel source.

While the keto diet may offer some health benefits, it also presents several nutritional concerns and potential side effects. It is crucial to consult a healthcare professional before starting this or any other restrictive diet to ensure it is safe and appropriate for your individual needs.

Frequently asked questions