What is a ketogenic diet and is it safe?

by Dr Suk Cho September 13, 2018

What is a ketogenic diet and is it safe?

Ketogenic, ketone, keto or ketosis diet has gained a huge following in the US.  There is firestorm of postings and ads on Facebook and other social media platforms.  The “keto craze” is ramping up on promises of quick weight loss by eating all the fat and protein or taking magic pills to get to ketosis (this is explained further below).  However, some research says this diet is an unhealthy way to lose weight and, in some instances, it can be downright risky.  In this blog article, I will cover what a Ketogenic diet is and clarify any issues based on the research that has been done thus far.


What is a ketogenic or ketosis diet? 

Ketogenic diet is a highly controversial topic in the scientific community, and I will try to break down all the key components here!  There are various versions of ketogenic diets. Basically, they are very low carbohydrate diets with most of the food energy coming from fat and protein.  According to Accurso et al., the dieters must have approximately 50 g of carbohydrates per day or 10% of energy from approximately 2000 kcal diet.  Other experts state that it requires less that 20g of carbohydrates per day (And, it is not per meal).  The purpose of this diet with very low carbohydrates is to promote the state of ketosis, or the fat burning state for one’s weight loss.  Your body uses the carbohydrates you eat for energy, so if we restrict how many carbohydrates we eat, then your body must get its fuel source from fat (or protein).  Those who took Biochemistry 101 will remember the Krebs cycle (or Citric Acid Cycle) which is the biochemical path our bodies use for extracting energy from carbohydrate, amino acids, and fat.  Byproducts of this fat burning state are ketones which are produced and build up in your bloodstream- We will call this as a nutritional ketosis or endogenous ketosis.  These byproducts-ketones are produced endogenously, meaning inside the body.   You can determine if you are in this fat burning state by purchasing urine ketone testing strips.   Ketosis is a mild form of ketoacidosis.  Ketoacidosis mostly affects people with type 1 diabetes. In fact, it is the leading cause of death of people with diabetes type 1. 

The ketogenic diet was developed initially to treat epilepsy in the 1920s.  In 1921, Rollin Woodyatt researched diabetic diets. He reported that ketones like β-hydroxybutyrate and acetones were produced by the liver in healthy people when they were starved or who consumed a very low carbohydrate and high fat diet (70% fat; 20% protein and 5% carbohydrate).  Russell Wilder built on this research and defined the term ketogenic diet to describe a diet that produced a high level of ketones in the blood.  His trial on a few epilepsy patients in 1921 was the first use of the ketogenic diet as a treatment for epilepsy.  This diet was largely abandoned when many new epilepsy seizure’s drugs came on the market.  And, some children who do not respond to these anticonvulsant drugs are still managed by this high fat very low carbohydrate diet.  Other therapeutic uses for the ketogenic diet have been studied for other disorders like Alzheimer's disease, autism, brain cancer, and Parkinson's disease.

There are two popular ketosis methods are being used in the market with various modified versions.  One is endogenous ketosis which triggered through eating very low carbohydrate or eliminate carbohydrate.  Another one is exogenous ketone diet, which is taking exogeneous ketones to trigger ketosis. 


What are exogenous ketones?

Exogenous ketones are a newer supplement having entered the market in just the past few years.  Most exogenous ketones are synthesized and consumed as a supplement.  There are various ketone supplements that are mostly ketone salts like sodium, calcium, or magnesium of Beta-hydroxybutyrate (BHB).  There is a key question if these salts will meet new dietary ingredients (NDI) or one can use them based on grandfathered in rule to use as a dietary supplement based on the products used prior to 1994.  Anyway, the marketers call these exogenous ketones which means that it was originated from outside of an organism.  

You may have heard “drink this Ketone salts and you’ll be in ketosis”.  What they are implying is that after you drink exogenous ketones you will see the presence of ketones when you measure blood ketone levels after an hour or so.  Because ketone strips measure ketones, you will see them on the strips after ingestion of BHB salts which is ketones. The result varies by the individual, but a typical boost is about 30 min - 2 hours.  So, when you see ketone indication on the ketone strip that doesn’t mean you are in nutritional ketosis and be able to stay in a ketosis state.   Your ketone levels will return to your baseline.  Most often, exogenous ketone marketers ask you to be on very low carbohydrate diet as well, so you may be reaching ketosis thru diet instead of exogenous ketone.  So, if you’re not doing endogenous ketosis, your exogenous ketones won’t really do much.  Exogenous ketone pills are not magic pills and you have to still in low carbohydrate diet, so I would not waste your money…


Does ketogenic diet help with weight loss?

Ketogenic diets have been shown to reduce weight quickly.  These Keto diets are probably among the "most studied" approaches to weight loss in recent times.  Some studies, suggest that a ketogenic diet is safe for significantly overweight or obese people and others believe these keto diets are not safe.  There are many research to support the weight loss of ketogenesis diets like Atkins diet.   One benefit is people can lose some initial weight rapidly.  This loss can then help encourage them to continue weight loss program. 

It is not for the faint of heart.  Carnivores get excited about eating a ton of meats like bacon (and there are some studies suggest that eating too much bacon can kill you sooner).  I have tried it and many of my friends have tried it!  It works but it has inherent problems.  The diet is very strict to be able keep it at very low carbohydrate level.  The problem is how long can you keep it up? Also, it doesn’t teach you the portion control that you need for long term benefit.  And, that is why many clinical studies point out that patients on low-carbohydrate diets regain some of their lost weight within a year because of sustainability and not being able to eat a balanced diet.


Are there risks associated with Ketogenic diet?

Keto diets have a proven track record in tackling obesity by helping them to lose weight quickly, and there are some concerns relating to long term safety and risks mainly due to lack of knowledge about the physiological mechanisms involved and no one has studied them for long term to recently.

Critics say the keto-type diets usually work only in the short term and can be unhealthy.  Some nutritionists claim that most of the lost weight is water weight initially.    Once your body enters ketosis, you also begin to lose muscle- muscle of protein is easier to metabolize then the fat.   When one enters starvation mode your body will fight to preserve and may be harder to lose weight at that stage.  It is also believed that Ketogenic can damage the heart, which is also a muscle.

Anyone with type 2 diabetes can benefit from weight loss and a reduced-carb diet because it will improve insulin sensitivity, but research has shown that moderate carbs with vegetables and fruits still can help with diabetes-so you don’t have to be in very low carbohydrate diet like ketogenic diet.  Keto diet may do more harm than good for the majority of patients, especially if they have any underlying kidney or liver issues. 

There are also some studies suggesting that ketogenic diets may increase the risk of insulin resistance that may lead to type 2 diabetes in certain animal model studies.   The researchers found that the main reason for decreased glucose tolerance in the keto diet-fed mice was due to insulin resistance in the liver.

There are also some studies suggesting that ketogenic diets may increase the risk of cancer for eating red meat and saturated fat. 

In a recent land mark study published in a high-quality peer reviewed publication on Lancet-public health, low carb diets like Atkins or ketogenic (keto) diets are shown to have a higher risk of mortality compared to moderate carb groups.  This result was reports after following a group of about 15000 for an average of 25 years.  The researchers found that those who got 45-55% of their energy from carbohydrates (the moderate carb group) had a slightly lower risk of death compared with very low carb groups.



Researchers estimated that, from the age of 50, people in the moderate carb group were on average expected to live for another 33 years.

This was:

  • ~4 years more than people who got 30% or less of their energy from carbs (extra-low-carb group)
  • ~2.5 years more than the 30%-40% (low-carb) group
  • ~1.1 years more than the 65% or more (high-carb) group

The findings were similar to previous studies, which included more than 400,000 people from more than dozen countries.  There are some limitations to the studies but again this suggests that very low carbohydrate diets have inherent problems. 

One should consume good carbohydrates from colorful vegetables, fruit, and whole grains since much research shows that greater consumption of too much animal proteins and fats has been linked to inflammation and ageing in the body.

Losing weight can help prevent diabetes.  Some studies showed that subjects can prevent the progression of developing diabetes through diet and exercise.  These subjects didn’t need to follow the keto program and restrict carbohydrates to just 20g per day to achieve this.

One study from 2003 followed 132 participants; half on a low carbohydrate diet restricting them to less than 30 carbohydrates per day, the other half on a low fat diet. These participants were then followed up with after one year. It was found that over 35% had dropped out, not being able to sustain such restrictive diets even for one year.  Once again, we see that both diets that are too restrictive are not sustainable for a long term. 

With restrictive diet, one will eventually start consuming a more normal amount of carbohydrates again, and immediately go out of ketosis or the fat burning state, and your body starts storing fat again.  In other words, you immediately start gaining weight. So whatever weight you lost on the diet, you gain back right away.  That is what research has shown.   How healthy do you think it is for your body to be in a starvation mode or high fat/protein diet mode (very low carbohydrate diet) to get to a ketosis state? 

In addition, you cannot get all the nutrition you need from this diet. You need foods from all the food groups for a healthy body. Now I can already hear some of you trying to tell me that cavemen didn’t have access to fresh fruit.  They sure didn’t just look how long they lived. What was their average lifespan? We have been evolving.  Someday, I will write on new science frontier called nutrigenomics….

I do believe that the Ketogenic diet can help you lose weight initially.  But one should be able to receive healthier weight loss with reduced calories with high lean protein and healthy loads of complex carbohydrates to that diet so that it is sustainable for long term.  As your body adjust to healthier choices of food and you become more aware of what constitutes a good choice then the diet becomes more enjoyable and one can succeed in maintaining an ideal weight for longer term.  Eating a high protein diet in form of lean meat or high quality protein meal replacements with high dietary fiber can catalyze good habits as well as help with satiety and hunger control.  I am a huge proponent of eating lean meat along complex carbohydrates from vegetables, fruits and whole grains to manage your weight and diabetes.

I hope I was able to shed light on the ketogenic diet debate.



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Dr Suk Cho
Dr Suk Cho

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