Skip to main content

6 Keto Diet Side Effects: Is the Ketogenic Diet Safe for You?

Keto Diet Basics for Beginners

Before starting a ketogenic diet, it is important to consult your physician first. There are many factors to consider, including your current state of health, age, health history, and genetics. You must know what the main keto diet side effects are before beginning a strict dietary plan.

Health Benefits and Side Effects of a Keto Diet

Radical shifts in your diet can be beneficial. Though, changing your eating habits can also have negative consequences if you are unaware of how your body will react. Some diets that are ideal for one person are not always appropriate for another.

This article provides a summary explaining the ketogenic diet, its possible side effects, and the benefits of going on the diet.


What is the ketogenic diet?

When you go on a ketogenic diet, you are significantly reducing your consumption of carbohydrates and increasing your intake of healthy fats with a moderate amount of protein.

What are healthy fats?

“Healthy fats” include extra virgin olive oil, coconut oil, avocado oil, avocados, nuts, seeds, and fatty fish. However, avoid eating “unhealthy fats” like harmful vegetable oils and trans fats.

What is ketosis?

On a typical high-carbohydrate diet, glucose and sugars from the carbs are used for energy. Conversely, on a keto diet, your body utilizes fat for fuel through a process called ketosis. In ketosis, your liver transforms the fat into ketones. In turn, these ketones are what your body, brain, tissues, and cells use to function.

Therefore, on a ketogenic diet, your body essentially becomes a fat-burning machine by shifting its main energy source.

4 Types of Keto Diets

Not all ketogenic diets are identical. After consulting with your doctor, if you decide to go on a keto diet, you should choose one that you are comfortable with and capable of sustaining.

There are four keto diets that vary in fat, protein, and carbohydrate percentages.

Standard Ketogenic Diet

  • 75% fat
  • 15 to 20% protein
  • 5 to 10% carbs

Targeted Ketogenic Diet

  • 65 to 70% fat
  • 20% protein
  • 10 to 15% carbs

High-Protein Ketogenic Diet

  • 60 to 65% fat
  • 30% protein
  • 5 to 10% carbs

Cyclical Ketogenic Diet

  • 75% fat
  • 15 to 20% protein
  • 5 to 10% carbs

*Cyclical Ketogenic Diet (off days)

  • 25% fat
  • 25% protein
  • 50% carbs
Scroll to Continue

*On a Cyclical Keto Diet, you follow a typical high-fat/low-carb diet for most of the week, followed by 1 or 2 “off days” of lower fat and increased carbohydrate consumption.

Keto Diet Side Effects

Before starting a ketogenic diet, you should familiarize yourself with the possible side effects. Although many people benefit from going on a keto diet, not everyone reacts the same way to it.

Some negative reactions could occur, such as weight gain, digestive issues, vitamin deficiencies, low energy, circulation problems, and other health risks.


Is the ketogenic diet safe for you?

Read the potential health problems associated with a keto diet highlighted below.

1. Increased Weight Gain After Stopping the Diet

Initially, when you begin a ketogenic diet, you will likely notice significant weight reduction in the first couple of weeks. Most of this is from lost water weight. The first week is the most difficult; however, your body will eventually adjust to the new eating regimen.

After a month of following a strict diet plan, you may be tempted to resort back to old eating habits. One cheat day becomes two. Then, before you know it, you have spent a whole week eating higher percentages of carbohydrates.

If you are not careful, this can create a yo-yo pattern in weight fluctuations which is stressful on the body. By shifting your diet back and forth in this way, your metabolism can have trouble adjusting which often leads to weight gain.

Therefore, before starting a ketogenic diet, make sure that it is something that you are capable of sustaining. Most importantly, make sure that your “cheat days” do not become “cheat weeks”.

2. Common Gut and Digestion Problems

You may also experience gut issues or digestive problems while on a ketogenic diet. Since you are restricting carbs, you will eat less starch and whole grains. Both are good for your gut bacteria.

On your cheat days, or whenever you must eat carbohydrates, it would be better to incorporate these types of “healthy carbs” to promote a strong microbiome.

Furthermore, it is quite common for people to suffer from constipation and/or diarrhea because of the higher fiber consumption while on a keto diet.

3. Vitamin and Mineral Deficiency

Strict versions of the ketogenic diet limit the amount of fruit, vegetables, and whole grains that can be eaten. All of these foods are very nutrient-dense, vitamin-rich, and full of antioxidants. By restricting fruit and vegetables at high levels, you may incur vitamin and mineral deficiencies.

Because of this, it is important to check up with your doctor regularly to make sure your body is receiving all of the vital nutrients that it needs. Consider taking a multivitamin or other health supplements while on a keto diet to reduce mineral deficiency risks.

4. Lower Energy and Athletic Performance

Recent studies have shown that ketogenic diets can affect your strength and endurance. Especially, athletes who partake in high-intensity sports may be limited to perform at peak levels for extended periods.

Therefore, if you are involved in sports that require prolonged endurance, you may want to think twice about going on a keto diet. It may significantly affect your performance, deplete your energy levels faster, and cause fatigue.

5. Potential Heart Problems and Blood Vessel Damage

On a more serious note, the long-term side effects of a ketogenic diet are unknown.

Some research shows that people who eat minimal carbohydrates can suffer from atrial fibrillation - a heart rhythm disorder. This can increase risks of developing heart conditions or suffering from a stroke.

However, these scientific studies are still in their infancy and many genetic factors could be in play. For the time being, there is not yet a clear cause/effect relationship. More research is required to explore how the keto diet affects heart health.

Similarly, blood vessels in the body could be affected negatively while on a high-fat diet. Though, it is not exactly the fat that is the problem per se. The main concern is when you suddenly shift from eating high-fat foods to high-carb foods that have a high glycemic index (GI).

For example, high-sugar foods like soda, candy, donuts, and other junk food all have a high GI. When you have a “cheat day” and consume these types of sugary treats, it could potentially damage your blood vessels.

Knowing this risk, you may want to stay on a strict ketogenic diet while abstaining from bags of potato chips and chocolate bars every weekend.

6. Risk of Gallbladder Disease and Pancreatitis

High-fat keto diets can increase your risk for gallbladder problems. Excess bile from fat consumption overstrains your liver. If you ever experience a lot of bloating or indigestion during a ketogenic diet, it may indicate that your body will not be able to tolerate it over extended periods of time.

Lastly, if you have a family history of pancreatitis or other serious conditions influenced negatively by high-fat intake, you should consider alternative dietary options.

A ketogenic diet can increase circulating fat in the bloodstream and cause acute pancreatitis - a sudden inflammation of the pancreas. If left untreated, severe pancreatitis could lead to further damage to your heart, lungs, kidneys, and other organs.

That being said, it is important to know your family health history. Again, always remember to consult with your physician before starting a keto diet.


The Health Benefits of a Keto Diet

Despite these negative side effects, the ketogenic diet can have significant, and often life-altering, benefits to your overall health. If your health history is non-conflictive, you are disciplined with your eating habits, and you can abstain from high-sugar foods long-term, then keto could be a solution for you.

Following a ketogenic diet has numerous health advantages. Below is a quick summary of how a keto diet can help alleviate pain, improve bodily functions, and treat chronic diseases.

Ketogenic Diet Health Benefits

  • Reduced Appetite
  • Fast Initial Weight Loss
  • Improved Cholesterol Levels
  • Lower Triglycerides
  • Lower Blood Sugar
  • Lower Blood Pressure
  • Treatment for Chronic Diseases

    • Metabolic Syndrome
    • Type-2 Diabetes
    • Bipolar Disorder
    • Dementia
    • Alzheimer’s
    • Parkinson’s
    • Cancer

Conclusion: Is the ketogenic diet safe?

If you are considering a keto diet, it is important to be aware of the negative side-effects that could potentially occur. Essentially, the main drawbacks of the diet are troublesome if you have a family history of liver conditions. Genetics will also play a key role in determining if it is an appropriate dietary option.

However, people with a healthy background and no conflicting genetic issues will likely do very well on a ketogenic diet. It is safe for the majority of individuals. As long as you can restrict high-GI sugary foods and commit to a strict keto diet over the long-term, then it could be a sustainable lifestyle choice for you.

In sum, a ketogenic diet is definitely worth considering if you want to lose weight, prevent chronic disease, and improve your overall health.

Finally, remember to consult with your health provider before beginning a new diet.

For more diet tips and nutritional advice, visit Health Benefits 101.



Poll 1: Keto Diet Safety

Poll 2: Keto Diet Side Effects

Video: Dr. D'Agostino on Nutritional Ketosis


RoadMonkey on September 27, 2019:

I went on the Atkins diet maybe 20 years ago and lost a lot of weight. I felt healthy and was the right weight for me but I allowed a few cheat days, which turned into cheat weeks! I really should go back on it because I enjoy the ketogenic diet BUT, it's difficult when you live with a person who doesn't need to lose weight and whose diet is probably the exact opposite of keto! Well that's my excuse and I'm sticking to it until I find a way that suits me to incorporate a keto diet for me, while providing him with the carbs he likes and needs. (He has digestive problems that mean that carrots, for instance, are very necessary for him.) I like carrots but can do without them if they aren't around. I think I have also got into the way of eating for eating's sake - habit. Not good. This is a useful summary of the different types of keto diet, I didn't even know there were different types now.

Related Articles