Ketogenic diet: an overview

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What is it?

The ketogenic diet, commonly known as the keto diet, is a high-fat, moderate-protein, and low-carbohydrate diet. When following a keto diet, the daily macronutrient intake is typically:

70-75% of calories from fat (~125-165 grams of fat per day)
20-25% of calories from protein (~80-125 grams of protein per day)
5-10% of calories from carbohydrates (~20-50 grams of carbs per day)

History

The ketogenic diet has been around for nearly a century. Its roots can be traced back to the 1920s when it was first developed as a treatment for children with epilepsy. The idea behind the diet was to mimic the metabolic changes that occur during fasting by forcing the body to burn fat for fuel instead of carbohydrates.

In the decades that followed, the ketogenic diet fell out of favor as new anticonvulsant drugs became available. However, interest in the diet was revitalized in the 1990s, when it was discovered that the diet could also be effective in helping people lose weight.

Since then, the ketogenic diet has become increasingly popular as a weight loss tool, and it has also been studied for its potential therapeutic benefits for a variety of other health conditions, including diabetes, cancer, and neurodegenerative diseases.

In recent years, the ketogenic diet has become a controversial topic, with some health experts claiming that it is not a sustainable or healthy way to eat. However, others argue that the diet can be beneficial in the short-term, especially for people who are looking to lose weight quickly.

Classical keto diet

The classical ketogenic diet is a medical therapy used primarily to treat epilepsy, and it requires strict adherence to a specific macronutrient ratio, with 90% of calories coming from fat, often under close medical supervision. While the term “keto diet” has been popularized in recent years, the majority of people who follow a “keto diet” are not following the classical ketogenic diet.

The keto diet that is commonly followed by the general population is often a less strict version of the classical ketogenic diet. It typically involves a higher protein intake and a lower fat intake, with a macronutrient ratio of around 70% fat, 25% protein, and 5% carbohydrates. This version of the keto diet is often referred to as the “modified Atkins diet” or the “low-carb, high-fat” diet.

What is ketosis?

The ketogenic diet works by inducing a metabolic state called ketosis. Normally, the body runs on glucose, which is derived from carbohydrates. However, when the body is in a state of ketosis, it burns fat for fuel instead of glucose. This shift in fuel source is triggered by a reduction in the amount of carbohydrates in the diet, which forces the body to turn to stored fat for energy.

When following a ketogenic diet, the goal is to reduce carbohydrate intake to a level that is low enough to trigger ketosis. This typically means consuming less than 50 grams of carbohydrates per day. To compensate for the lack of carbohydrates, the diet is high in fat. The remaining calories come from protein.

In a state of ketosis, the liver starts to produce molecules called ketones, which are used as fuel by the body’s cells, including the brain. This shift in energy source can result in a number of potential benefits, including weight loss, improved blood sugar control, and a reduction in inflammation.

How to get into ketosis?

If you are trying to get into ketosis, it is generally recommended that you limit your carbohydrate intake to 20-50 grams per day. This amount of carbohydrate restriction can help to deplete glycogen stores in the liver and muscles, which signals the body to start producing ketones for fuel.

It’s important to note that when you’re trying to get into ketosis, you’ll also need to consume a moderate amount of protein and a high amount of healthy fats to ensure that your body has the necessary building blocks to produce ketones. Eating too much protein can stimulate insulin production and decrease ketone production, so it’s important to keep protein intake moderate.

The time it can take to get into ketosis can be anywhere from a few days to a few weeks when following a low carbohydrate diet. Some people may enter ketosis within a day or two of significantly reducing their carbohydrate intake, while others may take longer.

Here are some tips that can help you more quickly go into ketosis:

Reduce your carbohydrate intake: To enter ketosis, you’ll need to significantly reduce your carbohydrate intake. The less carbs, the faster you may achieve ketosis. Avoid all high-carb foods, including grains, sugar, fruit, and starchy vegetables.
Increase your fat intake: To support ketone production and provide your body with energy, it’s important to increase your intake of healthy fats such as olive oil, avocado, nuts, and seeds.
Stay hydrated: Drinking plenty of water can help support the body’s transition to ketosis and prevent dehydration. Make sure to drink at least 8-10 glasses of water per day.
Exercise regularly: Engaging in regular physical activity, especially high-intensity interval training (HIIT), can help your body deplete glycogen stores more quickly, which can help you enter ketosis faster. Aim to exercise for at least 30 minutes per day, and include both strength training and aerobic exercise in your routine.
Consider intermittent fasting: Fasting for short periods of time (such as 16-24 hours) can help your body more quickly transition to ketosis by depleting glycogen stores and encouraging fat burning.

How easy to break out of ketosis?

As a general guideline, most people need to restrict their carbohydrate intake to less than 50 grams per day to maintain a state of ketosis. Some individuals may be able to consume slightly more, up to 100 grams per day, and still remain in ketosis, but this can vary.

There are several factors that can improve a person’s ability to remain in ketosis. Here are a few examples:

High activity level: People who engage in regular exercise or have physically demanding jobs may be able to consume more carbs and still remain in ketosis. This is because physical activity can increase the body’s demand for energy, which can help to burn off excess glucose and keep ketone production elevated.
Metabolic flexibility: Some individuals may have a higher degree of metabolic flexibility, which means they are able to easily switch between burning glucose and burning fat for fuel. This can allow them to consume slightly more carbs and still maintain ketosis.
Genetic factors: Certain genetic variations may make it easier for some individuals to remain in ketosis despite consuming more carbs. For example, some people may have a genetic variant that enhances their ability to produce ketones even in the presence of higher levels of insulin.
Prior low-carb or ketogenic diet experience: People who have been following a low-carb or ketogenic diet for an extended period of time may have developed greater fat adaptation and metabolic flexibility, which can make it easier for them to tolerate slightly higher carb intake while still maintaining ketosis.

It can take anywhere from a few hours to a few days to exit ketosis after resuming the consumption of carbohydrates in your diet.

If you consume a small amount of carbohydrates, it’s possible to return to ketosis relatively quickly, within a few hours to a day. However, if you consume a large amount of carbohydrates, it can take several days to re-enter ketosis as your body works to burn through the excess glucose and insulin levels return to baseline.

Potential benefits

Health benefits

It’s important to note that many of these benefits are mainly seen in specific populations, and most of the studies done on the ketogenic diet are short-term. Some researched benefits include:

Weight loss: The keto diet can lead to weight loss by promoting the use of body fat for energy, which can lead to a reduction in overall body fat and weight.
Improved blood sugar control: By reducing carbohydrate intake, the keto diet can improve blood sugar control in people with type 2 diabetes.
Increased insulin sensitivity: The keto diet can improve insulin sensitivity, which can lead to better blood sugar control and a reduced risk of type 2 diabetes.
Increased satiety: The high-fat content of the keto diet can lead to increased satiety and reduced appetite, which can lead to weight loss and improved blood sugar control.
Improved heart health: The keto diet may improve heart health by reducing risk factors such as high blood pressure and triglycerides.
Reduced seizures: The keto diet has been used for decades to help reduce seizures in children with epilepsy.

How good is it for weight loss?

Research on the effectiveness of the ketogenic diet for weight loss has produced mixed results. Some studies have found that the diet can lead to significant weight loss, while others have found little to no benefit.

A systematic review and meta-analysis of 13 randomized controlled trials found that the ketogenic diet led to a significant reduction in body weight, body mass index (BMI), and waist circumference compared to a control diet.

Another systematic review and meta-analysis of 12 randomized controlled trials found that the ketogenic diet led to significant weight loss compared to a control diet, but the weight loss was not significantly different from other low-carbohydrate diets.

However, other studies have found that the ketogenic diet is no more effective for weight loss than other diets. A randomized controlled trial of 63 obese adults found that the ketogenic diet did not result in significantly greater weight loss than a low-fat diet.

Another randomized controlled trial of 132 overweight and obese adults found that the ketogenic diet was no more effective for weight loss than a low-calorie diet.

It’s worth noting that the studies that show a significant weight loss with the ketogenic diet are usually of short duration (12 weeks or less) and more research is needed to determine the long-term effectiveness of the diet for weight loss. Factors such as adherence, calorie intake, and physical activity level can also play a role in the effectiveness of the diet for weight loss.

Potential risks

Health risks

The keto diet may not be suitable for everyone especially if you have any pre-existing health conditions. That being said, many of the health risks have been extrapolated, and the actual long-term effects and risks are not well understood. Some potential health risks include:

Nutritional deficiencies: The diet is relatively restrictive and can result in a lack of certain nutrients, especially if a person is not careful to eat a varied and balanced diet. This can include deficiencies in fiber, vitamins and minerals.
Kidney damage: The high protein and fat intake on the keto diet can put a strain on the kidneys, particularly for people with pre-existing kidney problems.
Liver damage: The keto diet may also put a strain on the liver, especially if a person has pre-existing liver disease.
Increased cholesterol: The high-fat content of the keto diet may lead to an increase in LDL cholesterol, which can increase the risk of heart disease.
Constipation: The low-fiber content of the keto diet can lead to constipation.
Ketoacidosis: In rare cases, the keto diet can lead to a dangerous condition called ketoacidosis, particularly in people with type 1 diabetes.

Keto flu

The “keto flu” is a term used to describe a group of symptoms that some people may experience as their body adjusts to a ketogenic diet. These symptoms can include:

Fatigue: As the body switches from burning carbohydrates for energy to burning fat, some people may experience fatigue.
Headache: Some people may experience headaches as their body adjusts to the new diet.
Nausea: Some people may feel nauseous as their body adjusts to the new diet.
Dizziness: The body may feel lightheaded or dizzy as it adjusts to the new diet.
Insomnia: Some people may experience insomnia as their body adjusts to the new diet.
Muscle cramps: Some people may experience muscle cramps as their body adjusts to the new diet.
Poor focus and concentration: Some people may experience poor focus and concentration as their body adjusts to the new diet.

These symptoms are caused by the body’s adjustment to the new diet, as it switches from burning carbohydrates to burning fat for energy. The symptoms usually occur within the first few days or weeks of starting the diet and typically go away within a week or two.

Here are some tips to manage keto flu:

Stay hydrated: Drink plenty of water and other fluids to stay hydrated and help your body adjust to the new diet.
Take electrolytes: The keto diet can cause an imbalance of electrolytes in the body, so taking supplements like sodium, potassium, and magnesium can help to alleviate symptoms of the keto flu.
Get enough sleep: Getting enough sleep can help to alleviate fatigue and improve overall well-being.
Increase physical activity: Gentle physical activity can help to alleviate fatigue and improve overall well-being.
Gradually transition to the diet: Gradually transitioning to the keto diet can help your body adjust more easily to the new diet.
Consult with a healthcare professional: Consult with a healthcare professional before starting the diet, especially if you have any pre-existing health conditions, they can help you to manage the keto flu symptoms and to ensure that the diet is safe for you.
Be patient: Remember that the keto flu symptoms are temporary and usually go away within a week or two. Be patient and stick to the diet, your body will eventually adjust to the new diet.

Is keto bad for your heart?

Some studies have suggested that the keto diet may increase the risk of cardiovascular disease due to the high intake of saturated fats. Saturated fats have been linked to increased levels of LDL cholesterol, or “bad” cholesterol, which can contribute to the development of heart disease.

A meta-analysis of randomized controlled trials published in the British Journal of Nutrition in 2013 found that the keto diet was associated with a significant increase in LDL cholesterol levels compared to a low-fat diet. However, the same study also found that the keto diet was associated with a significant increase in HDL cholesterol, or “good” cholesterol, and a significant decrease in triglyceride levels, which are both considered positive markers for cardiovascular health.

Overall, the research on the relationship between the keto diet and cardiovascular disease is still limited and conflicting. While some studies have suggested that the diet may increase the risk of heart disease, others have found no significant association.

Keto diet plan

Foods to have

The following types of foods are typically allowed on a ketogenic diet:

Meat and poultry: Beef, pork, chicken, turkey, and other meats are allowed on the keto diet.
Fish and seafood: Fish like salmon, tuna, trout, and shellfish like shrimp, crab and lobster are great options.
Eggs: Eggs are a great source of protein and healthy fats, and can be eaten in many different ways.
Low-carbohydrate vegetables: Leafy greens, broccoli, cauliflower, bell peppers, and other low-carbohydrate vegetables are allowed on the keto diet.
Healthy fats: Healthy fats like olive oil, coconut oil, avocado, nuts and seeds are an important part of the keto diet.
Dairy: Cheese, butter, cream, and full-fat yogurt are allowed on the keto diet.
Berries: Berries are a good source of antioxidants and are lower in sugar than other fruits, so they can be consumed in moderation.
Nuts and seeds: Nuts and seeds like almonds, macadamia nuts, sunflower seeds, and pumpkin seeds are allowed on the keto diet.

Foods to avoid

The following types of foods are typically avoided on a ketogenic diet:

Sugars: All forms of added sugars, such as table sugar, honey, syrups, and sweeteners are avoided on the keto diet.
Grains: All forms of grains, including wheat, rice, oats, and barley, are avoided on the keto diet.
High-carbohydrate fruits: Fruits like bananas, oranges, apples, and grapes are avoided on the keto diet.
Starchy vegetables: Vegetables like potatoes, sweet potatoes, and corn are avoided on the keto diet.
Legumes: Beans, lentils, and peas are avoided on the keto diet.
Processed foods: Processed foods like chips, crackers, and snack bars are avoided on the keto diet.
High-carbohydrate condiments and sauces: Condiments and sauces like ketchup, barbecue sauce, and teriyaki sauce are avoided on the keto diet.
High-carbohydrate drinks: Drinks like juice, soda, and sports drinks are avoided on the keto diet.

Can I have popcorn?

Popcorn can be part of a keto diet, but it’s important to choose the right type and limit your portion size to fit within your daily carbohydrate limit.

Air-popped popcorn is the best choice for a keto diet, as it is low in carbohydrates and calories, and contains fiber that can help you feel full. One cup of air-popped popcorn contains about 6 grams of carbohydrates, including 1 gram of fiber, making it a reasonable snack option on a keto diet.

Limit your portion size to a cup or two of air-popped popcorn to avoid going over your daily carbohydrate and calorie limits.

However, it’s important to avoid pre-packaged popcorn that contains added sugars, such as caramel corn or kettle corn. These types of popcorn can be high in carbohydrates and may not fit within your daily carbohydrate limit on a keto diet.

Example 7-day keto diet plan

Day 1:

Breakfast: 2 scrambled eggs with avocado and bacon
Lunch: Caesar salad with grilled chicken and a creamy Caesar dressing
Dinner: Baked salmon with broccoli and butter

Day 2:

Breakfast: Spinach, mushroom and feta omelette
Lunch: Tuna salad with mixed greens, and a creamy mayo dressing
Dinner: Beef stir fry with mixed vegetables and a teriyaki sauce

Day 3:

Breakfast: Greek yogurt with berries and chopped nuts
Lunch: Chicken Caesar salad
Dinner: Pork chops with a creamy mushroom sauce and a side of green beans

Day 4:

Breakfast: Bacon, avocado and egg breakfast bowl
Lunch: Greek salad with grilled chicken and a lemon vinaigrette
Dinner: Beef and broccoli stir fry with sesame oil and soy sauce

Day 5:

Breakfast: 2 boiled eggs and a coffee with some coconut oil
Lunch: Grilled chicken breast with a side salad
Dinner: Baked salmon with a side of asparagus

Day 6:

Breakfast: Greek yogurt with berries and chopped nuts
Lunch: Tuna salad with mixed greens, and a creamy mayo dressing
Dinner: Chicken and vegetable stir fry with a side of cauliflower rice

Day 7:

Breakfast: 2 scrambled eggs with avocado and coffee with heavy cream
Lunch: Caesar salad with grilled chicken and a creamy Caesar dressing
Dinner: Beef and broccoli stir fry with sesame oil and soy sauce

Snack ideas

Here are some keto-friendly snack ideas:

Cheese sticks or slices
Nuts such as almonds, pecans, or macadamia nuts
Olives
Jerky or beef sticks (make sure to check the ingredients for added sugars)
Nut butter (such as almond or peanut butter) with celery sticks or cucumber slices
Pork rinds
Guacamole with veggie sticks
Sliced deli meat with cheese or wrapped around pickles or cucumber slices
Coconut chips or flakes
Pickles or pickled vegetables
Kale chips
Edamame beans (in moderation, as they do contain some carbs)
Dark chocolate (at least 70% cocoa solids)
Low-carb veggies such as cherry tomatoes, bell peppers, or cucumber slices with hummus or tzatziki dip
Chia seed pudding made with coconut milk and vanilla extract

Supplements on keto

Most people don’t require supplements while on the keto diet, and if you’re starting out, you probably don’t need them. However, some commonly used supplements while on the keto diet include:

Magnesium: Magnesium is an essential mineral that can be lost through the diuretic effect of the keto diet. Magnesium deficiency can lead to symptoms such as muscle cramps, fatigue and headaches. Magnesium supplements can help to replenish magnesium levels and alleviate these symptoms.
Electrolyte supplements: Other electrolytes, such as sodium and potassium, can also be lost through the diuretic effect. Electrolyte supplements can help to replenish electrolytes and alleviate symptoms of the keto flu such as fatigue, headaches, and muscle cramps caused by electrolyte imbalances.
MCT oil: MCT oil is a type of saturated fat that can be easily converted into ketones by the liver, which can be used as an energy source. MCT oil can help to increase ketone levels and provide an alternative energy source for the body.
Fish oil: Fish oil supplements can provide a source of omega-3 fatty acids, which can help to support heart health and reduce inflammation. Omega-3 fatty acids can help to reduce inflammation and support heart health, which can be beneficial for overall health and well-being.
Vitamin D: Vitamin D is important for bone health and can be difficult to obtain through the keto diet alone, especially if you’re avoiding dairy. Vitamin D supplements can help to ensure adequate intake and support overall health.
Fiber supplements: The keto diet can be low in fiber, which can lead to constipation. Fiber supplements can help to alleviate this symptom and support digestive health.
Probiotics: Probiotics can support gut health and digestion. They can help to balance the gut microbiome, which can improve digestion and support overall health.

Supplements to avoid

Keto gummies

Keto gummies are marketed as a convenient way to supplement a ketogenic diet, but are not as beneficial as they seem. We suggest you avoid any keto gummies, as their cons often outweigh their pros. Here are a few reasons why keto gummies may not be useful for the ketogenic diet:

May promote weight gain: Keto gummies are often high in calories and sugar, which can lead to weight gain if consumed in excess.
May not be keto-friendly: Some keto gummies may contain added sugars and other ingredients that are not keto-compliant, which can kick you out of ketosis and make it harder to lose weight and achieve other benefits of a ketogenic diet.
Limited Nutritional Value: Keto gummies often contain minimal amounts of beneficial nutrients and are primarily made up of sugar alcohols and artificial sweeteners which can have negative effects on health.

BHB

BHB, or beta-hydroxybutyrate, is a ketone body that is naturally produced in the liver when the body is in a state of ketosis, such as during a ketogenic diet. BHB supplements are marketed as a way to increase ketone levels and enhance the benefits of the ketogenic diet. However, research suggests that supplementing with BHB may not be useful for those following a keto diet.

Firstly, the body already produces BHB naturally when it is in ketosis, so supplementing with BHB may not offer any additional benefits.

Secondly, BHB supplements are often marketed as a way to “boost” ketone levels, but it’s important to note that the benefits of the ketogenic diet do not come solely from high ketone levels.

The ketogenic diet works by reducing carbohydrate intake, which forces the body to use fat as its primary fuel source instead of glucose. This metabolic shift leads to many health benefits, including weight loss, improved blood sugar control, and reduced inflammation.

Simply increasing ketone levels through supplements may not offer the same benefits as following a well-formulated ketogenic diet.