Healthy Hormones

Keto Diet Pros and Cons

​Chances are you have heard about the Keto Diet ​​a lot from friends, coworkers, or family members.  It is also all over the news and social media.

​The popularity of the Keto Diet has soared over the past few years via marketing campaigns and word-of-mouth.

So what is the Keto Diet?  Is it safe?  Does it work?  What foods do you eat ​and what do you avoid?  What are the ​keto diet pros and cons?  What does the research show about it?  When should you consider using it?

I will answer these questions and many more in this article...​


​History of the Keto Diet

​Versions of the ketogenic (Keto) diet have been around for over 100 years.  It was used in the 1800s to help control blood sugar levels in patients with diabetes.  It was introduced as a treatment for epilepsy in children in the 1920s.  It has since been used as a treatment for various conditions, including cancer, dementia, and other neurological disorders.

Over the past 30 to 40 years, its popularity as a weight loss diet has skyrocketed.  It began with the Adkins Diet, which promoted a mostly protein (meat) based diet with moderate fat intake and low carbohydrates.  ​Other diets ​have since been developed such as the South Beach Diet, Whole 30, Paleo, and many others.  

The primary progression of these diets has been in the percentage of fat that is recommended.

​What is the Keto Diet?

​While Adkins, South Beach and other diets ​have a high amount of protein, the Keto Diet gets the majority of its calories from fats.  Protein levels are moderate, while carbs are extremely low (~5% on the traditional Keto).

The concept of the keto diet is to make your body burn fat for fuel instead of glucose.

The preferred fuel for our cells is glucose (sugar).  Glucose is derived from eating foods that contain sugar and carbohydrates.  That glucose is either used immediately for fuel or stored in the liver or muscles as glycogen.

With the keto diet, the body is deprived of the majority of food sources of sugar and carbs.  After 3-4 days, all stores of glucose in the body are used up.  The liver will then begin burning fat for fuel.  A bi-product of this process is the production of ketones (thus the name ketosis).

​Keto Diet vs Low Fat Diet

​Many of the major health organizations (AHA, ADA, etc) still hold the position that too much fat in the diet is a major cause of health issues.  In fact, most still recommend keeping fat intake to no more than 30% of the total calories.

However, many studies over the past decade have called this into question.  Many experts now recommend reducing the carbohydrate intake rather than fat.

So which is better a helping with weight loss?  Low car or low fat?

One study showed no weight loss difference between a low fat and a low carb diet.

Several other studies, however, show that low carb diets result in more weight loss than low fat diets, especially early.  Click here, here, here and here for examples.

​A big problem with most low fat diets is participants tend to replace the fat content in the diet with simple or processed carbs, which is much worse than eating fat.

​Benefits of the Keto Diet

​Potential Negatives of the Keto Diet

  • The keto diet can be hard for some people to follow.
  • The first 5-14 days on the keto diet may cause flu-like symptoms as your body converts to burning fat for fuel.  This is sometime called the "keto flu."  The best way to manage this is to increase fluid intake.
  • Keto may cause low blood sugar, especially initially.  Be especially careful if you are diabetic and taking a medication that lower glucose levels (such as sulfonylureas).
  • It may cause in increased risk for kidney stones.  This is typically more common in the high protein diets like Adkins.
  • Staying on the keto diet for a prolonged period of time can possibly lower bone density.  Another study, however, showed no significant change.
  • It may increase uric acid which can trigger a gout attack.  This is the highest risk within the first few days of starting the diet.  Reducing inflammation in the body will eventually lower the risk for gout.
  • The source of fat and protein in a keto diet is very important.  One study showed an increased death risk from people eating a keto diet that was using animal sources for the fat and protein vs plant-based fat and protein.
  • The keto diet is not recommended during time of rapid growth - pregnancy and breast-feeding.  Children must be closely monitored if on it.
  • It may cause constipation.  Push the vegetables.
  • After stopping the keto diet, ghrelin levels may rise which can increase the appetite temporarily.
  • ​It could potentially lower free thyroid hormone levels.  Monitor your thyroid levels regularly while on the diet, especially if you have know thyroid issues.

​How Long Should You Stay on the Keto Diet?

​The short answer is, it depends.  Some people feel great on the keto diet, while other people can feel fatigued or moody while on it.

Some experts feel that the true benefit of the keto diet would be to go in and out of ketosis, not necessarily stay in ketosis indefinitely.

I typically recommend giving the diet a good 4-6 weeks.  At that time, assess how you feel and monitor your labwork - blood sugar, insulin, thyroid, kidney function, and liver function.

If you feel good, you can continue on it for longer.  If you feel bad, consider slowly adding back some good whole food carbs (fruit, veggies, legumes) until you feel better.

Another option to consider is eating a strict keto diet for about 1 month every 3-4 months, then going back to a whole food, organic diet with more carbs during the other months.

Every body and every system is unique.  You may have to do trial and error until you find what eating plan best fits you.

​​How Do You Get Off of the Keto Diet?

  • Go slow.  Don't just go back to the way you used to eat.
  • Slowly increase complex carbs (fruit, veggies, beans) one meal per day.  If you are tolerating it, you can gradually add them to other meals.  Watch for bloating or gas and slow down adding them if it occurs.
  • Avoid simple carbs and sugars.  Remember, that's probably what got you to the point of needing to start the keto diet in the first place!
  • You might feel more hungry at first and might even have some blood sugar variations.  Watch your blood sugar and avoid the munchies.

Will You Gain Weight After Stopping the Keto Diet?

​The answer is maybe.  If you go right back to your previous poor eating habits, you will likely gain most if not all of the weight that you lost on the diet.

That is why it is so important to transition off of the keto diet slowly and carefully, preferably to a primarily whole food, organic diet.  Continue to avoid sugar and processed carbs (pasta, bread, doughnuts, etc).

If you do this right, your weight will most likely maintain at your goal weight that your worked so hard to achieve while on the keto diet.

​My Guidelines for Using the Keto Diet

  • The keto diet is a great choice for patients with seizure disorder or other neurological or cognitive conditions.
  • Great choice for patients with insulin resistance/type 2 diabetes.  If on diabetes medication, closely monitor your glucose levels and consult with your medical provider before starting the diet.  The medications may need to be reduced rapidly or even stopped.
  • ​Be careful of the sources of fats and proteins.  Plant sources are better than animal sources.
  • Eat plenty of whole, green vegetables.  You need the fiber and it is a healthier source of protein and fat.
  • Hydrate, hydrate, hydrate!  Most of us are dehydrated which will worsen potential side effects of the diet.
  • Consider doing keto for a limited time several times per year.  Eat a whole food, organic, primarily plant-based diet the other times.


​The keto diet is an extremely popular diet that works by reducing the amount of sugar and carbs consumed.  The majority of calories come from healthy fats, while protein intake is moderate.

After a few days, the lack of sugar in the diet forces the body to burn fat for fuel.  This results in the production of ketones.

The keto diet can cause significant weight loss and help reduce appetite.  It has been shown to help treat neurological and cognitive disorders.  It can also help reduce insulin resistance and lower cholesterol levels.

The keto diet can cause significant side effects early in its use.  It may also increase uric acid, worsen constipation, and may have an effect on thyroid levels.

It is important to eat from good sources of fat and protein, especially plants.

Make sure you hydrate well while on the keto diet.

​Now it's your turn...

Have you tried the keto diet?  What results did you have?

Di you have any side effects or other problems?

Leave any comments or questions in the comments section below.

About the Author Dr. Jeff Whelchel

Dr. Whelchel is a family physician who specializes in functional medicine, especially hormone optimization. He has over 20 years experience in private practice managing patients with various medical issues. His passion is helping patients reach their full potential of wellness and quality of life. He grew up in the Texas Panhandle where he currently lives. He is married and has 3 awesome children.

Leave a Comment:

Vanessa Anderson says June 12, 2019

Hey, Jeff! Curious if you have looked at Trim Healthy Mama? I, too, have spent time researching a lot of these “non-traditional” diets. I just can’t reconcile keto as a long-term lifestyle (which I appreciate you addressing, by the way). THM is interesting, in that it looks at the way foods are combined within a single meal. The method is: pick your protein, then add either a healthy fat or a healthy carb–but not both. The premise is: the carbs cause insulin release. If there isn’t any fat in the system, it can’t bind. Likewise, if you have high fat (as in keto) but no carbs, no insulin is secreted. A lot of THM is keto-like, but it is a more sustainable lifestyle long-term. No more yo-yo restrictive dieting. I would be curious to hear your thoughts. From your article, I bet we are similar in our outlook, we are just calling it different things.

    Dr. Jeff Whelchel says June 14, 2019

    Hi Vanessa. I have not studied that particular diet other than glancing at it. The concept sounds reasonable. I think current knowledge starts with the fact that we should reduce our carbs. Protein can be overdone, because it can actually convert into sugar. Any way of eating that is whole food, organic, low sugar, and low or no gluten is going to be beneficial in my opinion. The best diet or way to eat for anyone is the one that they can actually stick with! Thanks for writing.

Nutravolts says September 16, 2020

Thank you for sharing valued content. This is the best website where i found real information. Specially thank to Author.

I am John from Nutravolts. I am owner of Nutravolts. We sell keto diet products in UAE.

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