What Is the Keto Diet?
The original keto diet, called the ketogenic diet, was created in the 1920s when physicians designed a high-fat diet as a method of treating epilepsy in children.
It turns out they were on the right track because current scientific literature supports the use of the keto diet for that purpose.1 However, this approach is not regularly seen in practice because seizure medications are even more effective for managing epilepsy.2
As soon as the diet and weight loss industry caught wind that people could lose weight by following the keto diet, it exploded in popularity. Keto continues to be heavily marketed as a weight loss solution; you probably even know a handful of people who’ve tried it.
There are several variations of keto, but they all boil down to similar recommendations: avoid carbohydrates and eat high-fat foods.
How Does the Keto Diet Work?
The core principle of the keto diet is to change the primary source of fuel from glucose to fat stores. In the absence of carbs, your body will metabolize fat into ketones and use those for energy instead.
Devoted keto followers will test their urine, blood or breath using various ketone meters. These at-home tests will provide some indication of whether your body has successfully entered ketosis, meaning it is now burning fat instead of metabolizing glycogen stores.
How Do I Enter Ketosis?
Entering a metabolic state of ketosis is hard—really hard. Your body’s primary fuel preference will always be glucose, and going against nature comes with its challenges.
Generally, in order to enter ketosis, you need to keep your net carb intake below 50g per day. For context, one apple contains 14g of carbs. Some people can take up to a week before they enter ketosis, but every metabolism operates differently.
To maintain ketosis you need to continue to restrict carbs in your diet. If you begin to eat carbs, even high-quality carbs, your body reverts back to using glucose for fuel.
<p class="pro-tip"><strong>Learn about </strong><a href="/blog/low-carb-diets-weight-loss">low-carb diets for weight loss</a></p>
Why Is the Keto Diet Popular?
Over the last two decades, low-carb diets have exploded in popularity. People are frustrated with the lack of results in their weight loss efforts, and eliminating sugar sounds like a strategy that can reduce calorie intake.
People may experience a rapid weight loss during the first two weeks of Keto, but scientists attribute this to changes in water weight, not true weight.3
What Is Dirty Keto?
Some versions of the keto diet, called “dirty keto,” encourage people to eat foods that dieters are often told to avoid: cheese, eggs, bacon, and different high-fat meats. It’s easy to understand the temptation to try this diet plan if it promised you would lose weight while eating all these foods!
Even if the weight does come off, the impact of ultra-processed foods on your health is vicious. Ultra-processed foods have been linked to chronic diseases and even increase your risk of certain cancers.4
<p class="pro-tip"><strong>Learn about </strong><a href="/blog/cheese-metabolic-health">cheese and metabolic health</a>.</p>
Is the Keto Diet Related to Atkins and the Paleo Diet?
The Atkins diet is one of the most popular low-carb diets in existence, but it is even more restrictive than keto. Atkins mandates a carb intake below 20g per day, and many people suffer while following the Atkins diet long term.5 It is a grueling pursuit and extremely difficult to follow.
The Paleo or Paleolithic diet was inspired by hunter-gatherers who existed in the Paleolithic Era approximately 2.5 million years ago. Seriously. The principle of the Paleo diet encourages people to choose unprocessed foods as often as possible, often opting for raw foods rather than cooked.
Both of these low-carb diets promise weight loss and improved vitality. However, the scientific evidence to support these claims is absent.
<p class="pro-tip"><strong>Learn about </strong><a href="/topics/natural-nutrition">the benefits of eating whole, unprocessed foods</a></p>
Who Is a Good Candidate for the Keto Diet?
The ideal candidates for the keto diet (as it was intended) are the youth who suffer from epilepsy. Through keto, they experience fewer seizures and rely less on medication to manage their health.
Women who suffer from polycystic ovarian syndrome may benefit from following a keto diet as well. A small pilot study showed that five women who followed the keto diet experienced weight loss and increased insulin sensitivity.6 A study repeated in 2020 showed similar results.7
People who have diabetes, but are not on medications, may also benefit from the keto diet.
Who Should Not Try Keto
People with diabetes who take blood sugar-lowering medications should avoid the keto diet. The absence of dietary carbs combined with the presence of medications will push you into a danger zone for hypoglycemia (low blood sugar).
The keto diet is contraindicated for anybody who suffers or is currently recovering from an eating disorder. The restrictive nature of the keto diet can exacerbate disordered eating and can cause significantly more harm than good.
Women who are pregnant should also abstain from the Keto diet. While growing your baby, your nutrition and energy requirements are high, and limiting your food options will make it extremely difficult to meet both of your needs.
What Does the Keto Diet Look Like?
The keto diet favors high-fat foods, followed by protein, with as few carbs as possible.
The most commonly restricted foods in the keto diet include:
- All grains, including healthy quinoa and barley
- Baked goods and desserts like ice cream, muffins, and cookies
- All types of bread, bagels, and dinner rolls
- Most natural fruits (especially any fruit that will push your carb intake over 50g per day)
- Sugar-sweetened beverages including juices, pops, specialty coffee drinks, and alcohol
<p class="pro-tip"><strong>Learn about </strong><a href="/blog/low-gi-fruits">low-glycemic fruits</a></p>
Keto-Friendly Breakfast Examples:
- Egg, ham, and cheese roll-ups
- Avocado and egg scrambled with green peppers and cheese
- Peanut butter smoothie with almond milk and cinnamon
Keto-Friendly Lunch Examples:
- Lettuce wraps with grilled chicken, peppers, onion, and cheese
- Smoked salmon and avocado served over salad greens and turnips
- Cauliflower crust pizza with meat toppings, bacon, or simply vegetarian with cheese
Keto-Friendly Dinner Examples:
- Taco-inspired ground beef bowl with shredded cheese, lettuce, sour cream, and tomato
- Zucchini noodles with meat sauce and parmesan cheese
- BBQ shrimp skewers with grilled asparagus and cauliflower rice
Is All the Fat in Keto Healthy?
This is a great question and one that is still being researched. The immediate focus when studying the effects of a high-fat diet will be on cholesterol levels, which we hypothesize will increase.
Following the keto diet for just four weeks can lead to increased levels of low-density lipoprotein (LDL) cholesterol, which is the exact kind of cholesterol that has been linked to heart disease and the buildup of atherosclerotic plaque.8
From a nutritional perspective, the keto diet is unbalanced. Any diet that favors a single macronutrient (in keto’s case it is fat) will leave you exposed and vulnerable to deficiencies in other areas of your diet.
<p class="pro-tip"><strong>Learn about </strong><a href="/blog/macronutrients">balancing macronutrients for weight loss</a></p>
Can the Keto Diet Be Part of a Healthy Weight Loss Journey?
The keto diet is restrictive and intensive, and any signs of long-lasting weight loss results do not exist, yet.
However, there are elements within the keto diet that can be helpful to your weight loss efforts.
Paying closer attention to the foods you include in your diet can be eye-opening, and many people may not even realize they are consuming excess carbs.
Including healthy fats, such as avocado or nuts, with your meals can help you feel more satisfied and less snacky throughout the day. This can reduce the risk of eating excess calories later on.
<p class="pro-tip"><strong>Learn about </strong><a href="/blog/nuts-blood-sugar">the best nuts for managing blood sugar</a></p>
Transitioning Off the Keto Diet
If you decide to try the keto diet, you may wonder if you have to follow the diet forever. Many people intend to follow the keto diet, lose weight, and then return back to their normal eating habits.
Regaining weight after following a restrictive diet is common. Currently, there are no official guidelines on how to transition off the keto diet. The general recommendations are to slowly reintroduce high-quality carbs back into your diet and monitor your weight and health.
<p class="pro-tip"><strong>Learn about </strong><a href="/blog/sustainable-weight-loss">the benefits of sustainable weight loss</a></p>
Does the Keto Diet Have Any Negative Side Effects?
Many people who start the keto diet experience a phenomenon called the “keto flu.” Symptoms can present as early as two to seven days into starting the keto diet.
Those afflicted report feelings of headache, brain fog, fatigue, and nausea. These symptoms should subside as your body adjusts to your new normal eating habits.
Other potential negative side effects of keto include:
- Diarrhea (from excessive fat intake)
- Constipation (due to the low fiber intake)
- Brain drain or brain fog
- Keto breath: a distinct type of halitosis characterized by a fruity odor or nail polish remover scent
- Nutrient deficiencies
The keto diet is a low-fiber diet. People who suffer from gut conditions may want to stay away from keto. Low fiber intake has been linked to an increased risk of diverticulitis9 and colon cancer.10
So, Is Keto Worth Trying?
Looking strictly at the scientific evidence, keto is not worth trying. By diving into restrictive diets, you expose yourself to other health problems which can interfere with your long-term weight loss goals.
However, there are valuable takeaways from the keto diet that can be applied to a healthy weight loss journey. There is a benefit to bringing more awareness to your diet and your carb choices.
Cutting back on ultra-processed carbs will help stabilize your blood sugars, may help improve cardiovascular health, and could reduce your risk of certain cancers while supporting weight loss.
You can use your continuous glucose monitoring (CGM) device to monitor how dietary changes impact your glucose levels. Instead of going full tilt keto, can you opt for a gentler approach and join the keto-curious group instead.
Choose your carbs intentionally and refer back to the data in your CGM to make educated choices. The data should increase your confidence that the foods you choose to eat align with your health goals.
<p class="pro-tip"><strong>Learn about </strong><a href="/blog/what-is-a-continuous-glucose-monitor">how continuous glucose monitors work</a></p>
Get more information about weight loss, glucose monitors, and living a healthier life
Topics discussed in this article:
- Wheless J. W. (2008). History of the ketogenic diet. Epilepsia, 49 Suppl 8, 3–5. https://doi.org/10.1111/j.1528-1167.2008.01821.x
- Kapur, J., Elm, J., Chamberlain, J. M., Barsan, W., Cloyd, J., Lowenstein, D., Shinnar, S., Conwit, R., Meinzer, C., Cock, H., Fountain, N., Connor, J. T., Silbergleit, R., & NETT and PECARN Investigators (2019). Randomized Trial of Three Anticonvulsant Medications for Status Epilepticus. The New England journal of medicine, 381(22), 2103–2113. https://doi.org/10.1056/NEJMoa1905795
- Masood, W., Annamaraju, P., & Uppaluri, K.R. Ketogenic Diet. (Updated 2021 Nov 26). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Retrieved June 6, 2022, from: https://www.ncbi.nlm.nih.gov/books/NBK499830/
- Fiolet, T., Srour, B., Sellem, L., Kesse-Guyo, E., Alles, B., Mejean, C., et al. (2018). Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort. BMJ, (360), k322. https://doi.org/10.1136/bmj.k322
- Mahdi G. S. (2006). The Atkin's diet controversy. Annals of Saudi medicine, 26(3), 244–245. https://doi.org/10.5144/0256-4947.2006.244
- Mavropoulos, J. C., Yancy, W. S., Hepburn, J., & Westman, E. C. (2005). The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: a pilot study. Nutrition & metabolism, 2, 35. https://doi.org/10.1186/1743-7075-2-35
- Paoli, A., Mancin, L., Giacona, M. C., Bianco, A., & Caprio, M. (2020). Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. Journal of translational medicine, 18(1), 104. https://doi.org/10.1186/s12967-020-02277-0
- Burén, J., Ericsson, M., Damasceno, N., & Sjödin, A. (2021). A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial. Nutrients, 13(3), 814. https://doi.org/10.3390/nu13030814
- Anderson, J. W., Baird, P., Davis, R. H., Jr, Ferreri, S., Knudtson, M., Koraym, A., Waters, V., & Williams, C. L. (2009). Health benefits of dietary fiber. Nutrition reviews, 67(4), 188–205. https://doi.org/10.1111/j.1753-4887.2009.00189.x
- Aune, D., Chan, D.S.M., Lau, R., Vieira, R., Greenwood, D.C., Kampman, E., et al. (2011). Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies. BMJ, (343). https://doi.org/10.1136/bmj.d6617