In 2022, an estimated 22 million Americans turned to the ketogenic (keto) diet to help lose weight and improve health.^[1] While this high-fat, low-carbohydrate eating plan can help you drop pounds, “going keto” also has its challenges and downsides.

Read on to learn more about the keto diet’s pros and cons.

What is the ketogenic diet?

You might be surprised to learn that the keto diet isn’t new. In fact, it’s been around for more than 100 years as a dietary treatment for people with epilepsy who don’t respond to anti-seizure medications.^[2]

Most Americans who go keto today do so to manage their weight. In general, a keto diet is: ^[3]

• High in fats [1] (approximately 75% of daily calories)
• Low in carbohydrates (no more than 5% of daily calories)
• Moderate in protein [2] (no more than 20% of daily calories)

How does the keto diet work?

The goal of the keto diet is to bring on ketosis. When you’re in ketosis, instead of using blood glucose (blood sugar) for fuel, your body breaks down fat into an alternate fuel called ketones. It can take 2 to 4 days for your body to enter a state of ketosis.^[4]

Your liver makes ketones from stored fat. You need to eat more fats on a keto diet to increase this fat storage and help your liver make ketones.[3]  Since carbs can raise blood glucose levels, you need to cut back on carbs [4] to induce ketosis. The same is true for protein: Your body changes amino acid molecules in proteins into glucose.^[5] So, to stay in ketosis, you must also watch your protein intake.

What are the pros of going keto?

Numerous studies indicate that the keto diet can aid weight loss. It may also help if you’re at risk for, or already have, certain chronic conditions like diabetes.[5] 

Findings suggest that a keto diet may:

Promote weight loss

Some people drop pounds quickly—as much as 10 pounds in less than 2 weeks—when they start following a keto diet.^[6] However, much of this early weight loss is due to the diet’s diuretic (fluid excretion) effects. With a typical diet, unused energy is stored as glycogen molecules. Each glycogen molecule is attached to 3 grams of water. When your body burns through carbs, the body flushes out the used-up glycogen and water through urine and sweat.^[7]

Because you’re not actually losing fat, you may regain some of the lost weight as you take in more fluids and continue the diet plan. A meta-analysis of 13 studies found that people who followed a keto diet lost about 2 extra pounds per year compared to those who followed low-fat diets.^[8] A separate study found that following the keto diet may help curb hunger.^[9] As a result, you’re less likely to snack in between meals. You may continue to lose weight as you eat fewer calories.

Lower blood glucose levels

Research shows that cutting back on carbs and following a keto diet can lower blood glucose levels when you have Type 1 or Type 2 diabetes.^[10] It may also be helpful in managing blood glucose levels when you have prediabetes.[11] When you follow a keto diet, it may be possible to reduce how much insulin or other diabetes medications you take. ^[12]

You should consult your health care provider before making major dietary changes. Taking diabetes medications while following a keto diet can cause blood glucose levels to drop too low. Excessively low blood glucose levels (hypoglycemia) can cause headaches, confusion, a fast heart rate, and seizures.^[13] 

What are the cons of going keto?

While the keto diet can be an effective weight loss tool, many people find it difficult to follow such a restrictive diet for a long time. You may gain back lost pounds when you start eating more carbs and protein.  The long-term health implications of the keto diet are unknown due to limited research. ^[14] You should talk to your health care provider before starting a keto diet or making major dietary changes.

Other drawbacks of a keto diet include:

• Digestive and urinary problems: ^[15] Following a high-fat, low-carb diet can increase your risk of digestive issues, including constipation, diarrhea, and bloating. You’re also more at risk for developing kidney stones.
• Increased risk of heart disease: ^[16] A recent review of studies suggests that a high-fat keto diet raises the amount of artery-clogging cholesterol in the blood.^[17] And while some people on keto diets see a drop in high blood pressure, the improvement is often temporary.
• Low nutritional value: ^[18] When you drastically cut back on carbs like fruits and vegetables, you miss out on essential vitamins, minerals, fiber, and antioxidants needed for overall good health.

In summary: Proceed with caution when going keto

Because the keto diet is so high in fat—and limits healthy protein and carbs—you should consult a health care provider before committing to this dietary plan. It can take time to figure out what you can and can’t eat on a keto diet. Your health care provider may recommend seeing a registered dietitian to ensure you don’t miss out on important nutrients. You can also find keto-friendly meal suggestions and recipes on our smartphone app.    

Now that you know more about the keto diet, you may be curious about how to make smart shopping choices. The Sincerely Health nutrition tools in the grocery app can help.

You can start by downloading the Albertsons app. You’ll save $10* on groceries for creating an account. Next, create a personalized Sincerely Health nutrition profile to receive 1,000 points.

Your nutrition profile allows you to:

• Set specific nutrition goals.
• Earn 10 points for items you purchase for a maximum 100 points per order (that’s 10 items at 10 points each).

FAQs about the keto diet

How long does the keto diet take to work?

Some people lose up to 10 pounds in less than 2 weeks when they start following a keto diet.^[19] But you may regain some of the lost weight as you take in more fluids and continue the diet plan.

Does the keto diet work long term?

Many people find it difficult to follow such a restrictive diet for a long time. You may gain back lost pounds when you start eating more carbs and protein. Experts are still researching the diet’s long-term health implications.

Sign up for Sincerely Health and create a nutrition profile to help you get healthy today!

Download your app on the App Store today

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[1] Harvard Kenneth C. Griffin Graduate School of Arts and Sciences. Keto – It’s Probably Not Right for You. Last reviewed May 10, 2023. https://sitn.hms.harvard.edu/flash/2023/keto-its-probably-not-right-for-you/#

[2] Epilepsia. History of the Ketogenic Diet. Last reviewed November 4, 2008. https://onlinelibrary.wiley.com/doi/10.1111/j.1528-1167.2008.01821.x.; Epilepsy Foundation. Ketogenic Diet. Last reviewed October 25, 2017. https://www.epilepsy.com/treatment/dietary-therapies/ketogenic-diet

[3] Food Insight. What to Know Before You Go Keto. Last reviewed February 14, 2023. https://foodinsight.org/keto-diet-101-what-to-know-before-you-commit/

[4] Harvard Health Publishing. Can the Keto Diet Help Me Lose Weight? Last reviewed March 28, 2024. https://www.health.harvard.edu/newsletter_article/can-the-keto-diet-help-me-lose-weight

[5] Harvard T.H. Chan School of Public Health. Diet Review: Ketogenic Diet for Weight Loss. https://nutritionsource.hsph.harvard.edu/healthy-weight/diet-reviews/ketogenic-diet/

[6] StatPearls. Ketogenic Diet. Last reviewed June 16, 2023. https://www.ncbi.nlm.nih.gov/books/NBK499830/#

[7] Harvard Kenneth C. Griffin Graduate School of Arts and Sciences. Keto – It’s Probably Not Right for You. Last reviewed May 10, 2023. https://sitn.hms.harvard.edu/flash/2023/keto-its-probably-not-right-for-you/#

[8] British Journal of Nutrition. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. Last reviewed May 7, 2013. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/verylowcarbohydrate-ketogenic-diet-v-lowfat-diet-for-longterm-weight-loss-a-metaanalysis-of-randomised-controlled-trials/6FD9F975BAFF1D46F84C8BA9CE860783

[9] Obesity Reviews. Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Last reviewed November 17, 2014. https://onlinelibrary.wiley.com/doi/10.1111/obr.12230

[10] Nutrients. Low-carb and Ketogenic Diets in Type 1 and Type 2 Diabetes. Last reviewed May 2019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6566854/

[11] PLoS One. A Randomized Pilot Trial of a Moderate Carbohydrate Diet Compared to a Very Low Carbohydrate Diet in Overweight or Obese Individuals with Type 2 Diabetes Mellitus or Prediabetes. Last reviewed April 9, 2014. https://pmc.ncbi.nlm.nih.gov/articles/PMC3981696/

[12] Cleveland Clinic Health Essentials. Here’s the Deal with the Keto Diet and Type 2 Diabetes. Last reviewed July 24, 2022. https://health.clevelandclinic.org/is-the-ketogenic-diet-safe-for-people-with-diabetes

[13] Cleveland Clinic. Hypoglycemia (Low Blood Sugar). Last reviewed January 31, 2023. https://my.clevelandclinic.org/health/diseases/11647-hypoglycemia-low-blood-sugar

[14] Current Problems in Cardiology. Ketogenic Diet and Cardiovascular Risk : State of the Art Review. Last reviewed March 2024. https://www.sciencedirect.com/science/article/pii/S0146280624000410

[15] StatPearls. Ketogenic Diet. Last reviewed June 16, 2023. https://www.ncbi.nlm.nih.gov/books/NBK499830/#

[16] Current Problems in Cariology. Ketogenic Diet and Cardiovascular Risk : State of the Art Review. Last reviewed March 2024. https://www.sciencedirect.com/science/article/pii/S0146280624000410

[17] Current Problems in Cariology. Ketogenic Diet and Cardiovascular Risk : State of the Art Review. Last reviewed March 2024. https://www.sciencedirect.com/science/article/pii/S0146280624000410

[18] StatPearls. Ketogenic Diet. Last reviewed June 16, 2023. https://www.ncbi.nlm.nih.gov/books/NBK499830/#

[19] StatPearls. Ketogenic Diet. Last reviewed June 16, 2023. https://www.ncbi.nlm.nih.gov/books/NBK499830/#

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