An Overview of the Keto Diet

Medically Reviewed By Amy Richter, RD

The ketogenic, or “keto” diet, is an eating plan that focuses on consuming healthy fats and some protein while limiting carbohydrates. Some evidence suggests that it may help people lose weight, regulate their blood sugar, and even reduce seizures. Though it may provide some benefits, the keto diet can also be difficult to follow and may result in nutrient deficiencies or symptoms like nausea and vomiting. The keto diet should be undertaken with the supervision of a qualified healthcare professional.

Read on to learn more about the keto diet.

What is the keto diet?

A salad with salmon and a hard-boiled egg
Nadine Greeff/Stocksy United

The keto diet is a dietary regimen that recommends:

  • high consumption of healthy fats
  • moderate consumption of protein
  • low consumption of carbohydrates

The idea behind the keto diet is that by reducing your carbohydrate intake to a minimum, your body will enter what is called “ketosis.” Ketosis is a metabolic state in which your body burns stored fat for fuel instead of carbohydrates.

This process then leads to ketogenesis, or the production of ketones, which are molecules that become an alternative energy source for the body and brain.

The main goals Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source of the keto diet are to reduce overall body fat and improve metabolism, which is how the body turns the food you consume into energy.

Types of keto diets

There are different types Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source of keto diets based on the distribution of fats, protein, and carbohydrates:

  • Standard ketogenic diet: This typically contains 70% fat, 20% protein, and only 10% carbohydrates. 
  • Cyclical ketogenic diet: This involves increasing your carbohydrate intake significantly in between keto diet cycles. For example, one keto cycle may consist of 5 days following the recommended eating plan. Next, you follow a high carbohydrate diet for 2 days.
  • Targeted ketogenic diet: This diet allows you to include extra carbohydrates, particularly during periods of intense physical activity.
  • High protein ketogenic diet: This contains 60% fat, 35% protein, and 5% carbohydrates. 

What can you eat on the keto diet?

The keto diet promotes high fat and moderate protein intake.

Healthy fats

The keto diet emphasizes eating lots of healthy fats, found in foods like:

  • avocados
  • nuts and seeds
  • olive oil
  • fatty fish like salmon

Protein

Protein food sources include:

  • meats
  • fish
  • eggs
  • dairy products like cottage cheese

Protein is a key part of the keto diet but is consumed in moderation to prevent Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source excessive gluconeogenesis. This is a process where the body produces glucose, or sugar, from non-carbohydrate substances.

Low carbohydrate foods

You can also eat low-carbohydrate foods such as:

  • broccoli
  • cauliflower
  • zucchini
  • spinach

Learn more about 10 keto-friendly fruits.

What should you limit on the keto diet?

The keto diet typically restricts carbohydrate intake. In particular, this includes foods high in starches or refined sugars, such as:

  • bread and pasta
  • potatoes and other starchy vegetables 
  • legumes such as beans and lentils
  • sugary sodas
  • honey and syrups
  • juices and cocktails
  • other beverages with added sugars

What are some potential benefits of the keto diet?

The following are some potential health benefits of the keto diet.

Weight loss

The keto diet may be beneficial for those wanting to lose weight.

A 2020 analysis of several studies Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source noted that keto diets were more effective in reducing body weight in people with overweight and obesity than low fat diets.

Another research analysis Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source noted that the keto diet may reduce the amount of a type of fat called triglycerides in the blood and lower body weight in people with type 2 diabetes.

Regulation of blood sugar levels

The keto diet may help regulate blood sugar levels, according to a 2020 analysis of clinical trials Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source . This could benefit people with type 2 diabetes or insulin resistance when the body’s cells don’t respond to insulin as they should and, therefore, can’t effectively use glucose.

Reduction of heart disease risk

The keto diet may reduce the risk of heart disease in a few ways.

A 2023 research review Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source found that the keto diet may:

More research is needed to determine the keto diet’s exact heart benefits.

Treatment of epilepsy

The keto diet was originally developed Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source to reduce the frequency and severity of seizures associated with refractory epilepsy, which is epilepsy that doesn’t respond well to medications. Since then, some research has shown Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source that it may benefit certain people with epilepsy, including both children and adults.

However, more research is needed to evaluate the effectiveness of the keto diet on various types of seizures at different severities.

Learn more about the keto diet and epilepsy.

Are there risks associated with the keto diet? 

Though the keto diet may offer various potential benefits, it is important to approach it with caution and undertake it only with the help of a registered dietitian or other healthcare professional. The following are some potential risks and challenges associated with the diet.

Nutrient deficiencies

Due to its emphasis on some foods and restrictions around others, the keto diet may not promote a well-balanced eating plan. This may lead to nutrient deficiencies, making it unsuitable for groups like children and people who are pregnant or nursing.

Adherence difficulties

It may be difficult to follow the strict rules of the keto diet. Not following the diet closely may then reduce its potential benefits.

Chronic conditions

A 2020 research review Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source noted that the keto diet may not be suitable for people with some acute or chronic conditions, including those who are:

Side effects

The same review highlights that some side effects, collectively known as the “keto flu,” may occur when you start the keto diet. These include:

Follow the keto diet only if you have access to a registered dietitian or other qualified healthcare professional.

Summary

The keto diet emphasizes fat and protein intake while limiting carbohydrates. Some evidence suggests that it may help with weight loss, regulate blood sugar levels, reduce heart disease risk factors, and manage epilepsy.

However, more research is needed to determine the exact benefits of the eating plan. In addition, the diet isn’t suitable for everyone and may increase your risk of nutritional deficiencies and side effects like dizziness or fatigue.

Talk with a qualified healthcare professional before trying the keto diet.

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Medical Reviewer: Amy Richter, RD
Last Review Date: 2024 Jan 24
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