Many readers asked me recently to review what they call the “ketogenic diet craze.”
“The Ketogenic Diet” seems to be the new buzzword in the Paleo community this year. Let’s take a look and see what’s going on with this “new” approach.
New Word, Similar Diet
According to the article “The Beginner’s Guide to the Ketogenic Diet” at Ruled.me, here’s the definition of the ketogenic diet:
“A keto diet is well known for being a low carb diet, where the body produces ketones in the liver to be used as energy. It’s referred to as many different names – ketogenic diet, low carb diet, low carb high fat (LCHF), etc.”
Diet Doctor goes a bit further and says:
“A ketogenic diet, or keto diet, is a very low-carb diet, which turns the body into a fat-burning machine. It has many potential benefits for weight loss, health and performance, but also some potential initial side effects.”
A Rose by Any Other Name…
Let me state the obvious: the ketogenic diet is a new word for roughly the same, old, boring, low-carb diet.
Whether you call it ketogenic, Atkins, or very low-carb, ultra Paleo or whatnot, you’re describing an approach that is simply a variation on the same theme.
A ketogenic diet restricts carbohydrates to create a state of ketosis, where the body must rely on fat and ketone bodies for energy.
Recent promoters of the Ketogenic Diet have improved their diet to make it safer, by placing a limit on protein consumption and encouraging the consumption of more plant foods and fewer animal products. But, it’s otherwise the same thing.
For example, in most YouTube videos on the subject where people explain what to eat daily on the ketogenic diet, we do not have anything other than a traditional Atkins Diet. In this video, for example, here’s the daily meal plan:
- Breakfast: four slices of bacon, four whole eggs, chives, and spinach.
- Lunch: Burger with ground beef (20% fat), with mushrooms, cheese, one slice of tomato and onion. Asparagus for vegetables, with olive oil and Parmesan cheese.
- Dinner: chicken wings, “mashed” cauliflower, in butter.
Do you see any difference with the Atkins Diet?
An article by Authority Nutrition is a bit more explicit:
The ketogenic diet (keto) is a low-carb, high-fat diet. It lowers blood sugar and insulin levels, and shifts the body’s metabolism away from carbs and towards fat and ketones.
Different Types of Ketogenic Diets
There are several versions of the ketogenic diet, including:
Standard ketogenic diet (SKD): This is a very low-carb, moderate-protein and high-fat diet. It typically contains 75% fat, 20% protein and only 5% carbs (1).
Cyclical ketogenic diet (CKD): This diet involves periods of higher-carb refeeds, such as 5 ketogenic days followed by 2 high-carb days.
Targeted ketogenic diet (TKD): This diet allows you to add carbs around workouts.
High-protein ketogenic diet: This is similar to a standard ketogenic diet, but includes more protein. The ratio is often 60% fat, 35% protein and 5% carbs.
In the same article, a sample menu is provided:
- Breakfast: Bacon, eggs and tomatoes.
- Lunch: Chicken salad with olive oil and feta cheese.
- Dinner: Salmon with asparagus cooked in butter.
As you can see from this listing, this is very similar to an Atkins Diet.
Atkins Menu Comparison
If you look at what a daily menu on the Atkins diet is like, you’ll find a similarity:
- Breakfast: Tex-Mex Egg Scramble
- Lunch: Tuna and veggie Salad
- Dinner: Beef and vegetables, with avocado
Both diets try to restrict carbohydrates to the strict minimum to create a “state of ketosis.”
Ketosis Is Not Fun
Before we go further, we have to define what is ketosis.
The ketogenic diet means a diet that causes the body to enter a state of ketosis, the same that happens during fasting.
What is ketosis?
Under normal circumstances, the body’s energy comes from blood glucose.
In ketosis, some of the body’s energy comes from ketone bodies, which are a product of fat metabolism.
Some people, like “Dr. Myhill,” who has a website that looks like Wikipedia (is she trying to fool people that way?) state things like:
The entire body uses ketones in a more safe and effective way than the energy source coming from carbohydrates – sugar AKA glucose. Our bodies will produce ketones if we eat a diet devoid of carbs or a low carb diet (less than 60 grams of carbs per day).
However, when you check her references, you realize she has no proof for her statements.
It’s important to understand that ketosis is not the primary way of energy production for the body.
It occurs automatically when glycogen stores are depleted — so when the body is running empty on all carbohydrate stores and not enough is provided through eating to replenish them.
Water fasting for more than 3-4 days on water depletes all glycogen reserves in the body and results in ketosis.
Restricting carbohydrates to a strict minimum can also create ketosis.
Being in a permanent state of ketosis is not usual for human beings. Even the Inuits, who consumed a very high-fat, high-protein diet, did not develop ketosis, perhaps to some adaptation to their diet.
Ketosis and Weight Loss
One common misunderstanding is that the ketogenic Diet automatically results in the body burning its fat reserves.
But… that will only happen if there’s a caloric deficit!
If you consume exactly the number of calories that you need on a ketogenic diet, you will not burn body fat. But you will still be in a state of ketosis because the body is forced to burn fat from food to produce ketone bodies.
Ketone Bodies Are Acidic
Water fasting can lead to many health improvements, but it’s a temporary cure.
Ketone bodies are acidic, and the body must buffer the acidity through various ways, which places a burden on the body to maintain proper PH.
How do you know if you’re in ketosis?
You can check your urine using a strip used to measure ketones.
And you can also smell your breath. If it smells like acetone, you may be in ketosis! (When you think of acetone, think of nail polish remover or paint thinner to get an idea of what it should smell like).
It’s possible for the body to adapt to ketosis and after 2-4 weeks manage relatively well on it. But it’s not the preferred state for the human body, and there’s no evidence that any human group has ever lived in a permanent state of ketosis.
Weight Loss Comes From Calorie Deficit, Not Carbohydrate Restriction
The main benefit of the ketogenic diet is, of course, weight loss, and we could even say that most of the other benefits come from weight loss.
- Lowers cholesterol.
- Improves insulin sensitivity.
- Reduces inflammation.
- Reduces your risk of cancer.
- Improves sleep.
- Improves immune function.
- Can eliminate aches and pains.
- Reduces overall risk of disease.
The Ketogenic Diet has been successfully used by many people to lose weight.
Losing weight will lead to many health improvements, no matter what the method.
But, wouldn’t it be better to choose a weight loss method that also improves your health in other ways? One that doesn’t promote disease? One that is sustainable?
Does the Ketogenic Diet Offer a Metabolic Advantage?
I will not deny that drastically restricting your intake of carbohydrate to 5 or 10% of your total calories can lead to some weight loss.
Being in ketosis is a potent appetite suppressant, and most people end up losing weight.
However, the claim made by many proponents of this diet is that it offers some metabolic advantage.
In other words, that if someone goes from consuming 3000 calories a day to:
- 2000 calories on a Ketogenic Diet
- 2000 calories on a low-fat, plant-based diet
… that the Ketogenic dieter would have an advantage over the person on a low-fat diet, consuming the same number of calories.
Is there a metabolic advantage?
The answer is NO!
Most studies on the subject are unreliable because food intake is not precisely controlled. Participants are asked to recall their food intake, leading to inaccurate measurements.
Metabolic ward studies confine participants to a controlled environment.
In a recent study of this kind, a ketogenic diet was found to offer no metabolic advantage over a traditional diet. The ketogenic diet contained only 31 grams of carbohydrates per day! (Versus 300 grams on the control diet).
Ketogenic diets were also shown to cause a small muscle loss, and ultimately slow down weight loss.
Another such study showed that calorie for calorie, low-fat diets result in more body fat loss. This study is interesting because they used a truly low-fat diet (17 grams of fat per day). But, to be fair, the “Reduced Carbohydrate” diet reduced total intake to 141 grams a day, which some might not view as truly ketogenic.
This study demonstrated that calorie for calorie, restriction of dietary fat led to greater body fat loss than restriction of dietary carbohydrate in adults with obesity. This occurred despite the fact that only the carbohydrate-restricted diet resulted in decreased insulin secretion.
In the same vein, but not as scientific, is a BBC documentary called “The Truth About Sugar,” where two identical twins go on two different diets: one is truly low-carb, and one is truly low-fat, high-carb.
The BBC documentary used to be available on YouTube, but I can’t find the full video now.
Both twins lost weight, but the twin eating the “sugar diet” lost more body fat, in spite of lower total weight loss.
The Low-Carb Twin:
– Became pre-diabetic
– Lost to the low-fat twin in a cycling challenge
– Lost to the low-fat twin in cognitive tests
– I think also lost more muscle mass at the end (if I can find the original video, I could confirm that).
Some might argue that their diet was not healthy because the low-carb twin did not even eat vegetables. He also ate a very high-protein diet, and in a more careful ketogenic approach, one would place a limit on protein. But, it’s clear by ALL standards that he ate a ketogenic diet. The low-fat twin did not have a very healthy diet either, but his health ended up better in every way.
Looking at the Alleged Benefits of a Ketogenic Diet
I reviewed most of the popular articles on the ketogenic diet and looked at each and many claims, and the research they used to back them off.
Let’s look at the most common claims one by one:
Is there evidence that ketogenic diets are better than a healthy plant-based (low-fat) diet for weight loss?
One study compared the Ornish Diet, the Zone Diet, with a Ketogenic Diet. The Ketogenic diet did the best regarding weight loss. But what’s my problem with this study? It was not done in a controlled environment, and instead used the usual tricks of “coaching” participants to follow their diet.
Whenever researchers compared a low-fat to a low-carb diet in a metabolic ward environment, we’ve seen that there was no advantage to restricting carbohydrates.
But it’s possible that Ketogenic Diet may be useful to some people in losing weight because of the potent appetite suppression induced by ketosis.
In that case, the worry becomes health in the long-term.
On a ketogenic diet, you’re eliminating some of the healthiest food items (fruit, beans, etc.) while overeating animal protein. As we’ve seen, most people who follow Ketogenic Diets end up eating lots of bacon, eggs, meat, and fish. Almost all studies done on these diets show an increase in LDL cholesterol.
Type 2 Diabetes
There is no proof that ketogenic diets are of any help in type 2 diabetes beyond the benefits that come from weight loss itself. Ketogenic diets can help diabetics, but the benefits come from weight loss, not the diet itself.
To prove that a diet can help diabetic patients without counting on any weight loss benefits, you would have to design a study where patients do not lose any weight during the study while changing the types of food they eat.
This study was done with a high-carbohydrate, low-fat plant-based diet.
What’s surprising about this study is that it showed what a low-fat plant-based diet could do without any weight loss whatsoever!
Many of the participants could discontinue insulin therapy altogether just by changing the foods they ate. Again, without losing any weight!
To my knowledge, this has never been never done with a ketogenic diet. Until then, we can assume that all the glucose management benefits from ketogenic diets come from the weight loss alone.
Ketogenic Diets usually lead to weight loss, which is something positive when it comes to heart health. Any amount of weight loss often leads to lowering of cholesterol in the short-term. Low-carbohydrate diets appear to impair artery function (see here and here.)
Most studies I have seen on the ketogenic diet, cited for their benefit, do not show significant improvements in blood lipids. HDL tends to be somewhat higher, but also total cholesterol and LDL (see here).
The most important fact though, is that there’s not a single study or even smallest amount of evidence to show that you can achieve powerful heart health benefits, such as the ones in the Ornish and Esselstyn studies, on a ketogenic diet.
In other words: you can reverse heart disease on low-fat, plant-based diet. There’s no evidence you can do the same on the Ketogenic Diet.
So which diet do you think is best for your heart?
Mental Clarity on Ketosis
In an article on the Ketogenic Diet, Dr. Axe writes:
Both in terms of how it feels physically and mentally, along with the impact it has on the body, being in ketosis is a very different than a “glycolytic state,” where blood glucose (sugar) serves as the body’s energy source. Many consider burning ketones to be a much “cleaner” way to stay energized compared to running on carbs and sugar day in and day out.
What’s very strange in this description is that Dr. Axe tries to imply that the body can just as efficiently run in a state of ketosis as when using its regular fuel: glucose. There is no such thing as a “glycotylic state, ” but rather it’s the usual process of energy production under normal circumstances when we have access to some form of carbohydrates!
The claim that it’s a “much cleaner way to stay energized” has absolutely no scientific basis, which is why there is no proof backing up this ridiculous statement.
It’s possible that entering a state of ketosis intermittently, through fasting or dietary restriction, may boost cognitive function, as some studies seem to suggest that (such as this one) . This could even improve memory function and prevent Alzheimer’s disease.
Fasting seems to be a more normal and healthy way to benefit from occasional states of ketosis, and it offers many other advantages as well that a Ketogenic Diet can’t begin to approach.
Being in a permanent state of ketosis doesn’t any proven benefits on cognitive function, and I would expect the opposite to be true.
Ketogenic diets have been successfully used in the treatment and prevention of seizures in epilepsy.
But, it’s important to note some researchers who have used these diets to treat epilepsy in children also recognized that this was a temporary treatment. They found that it can initiate heart disease in children.
On the whole many questions remain, such as this study indicates.
Poorly Designed Studies
You might come across many studies on the Ketogenic Diet, where they compared a very low-carbohydrate diet to a low-fat diet. However, the flaw in most of these studies, such as this one is that:
- The low-fat diet isn’t low-fat at all (30% fat). In this study, it states: Foods encouraged during the low fat diet included whole grains (breads, cereals and pastas), fruit/fruit juices, vegetables, vegetable oils, and low fat dairy and meat products.
- They’re not comparing the ketogenic diet to a truly healthy plant-based diet.
- They’re usually not done in a controlled environment, and instead, rely on participant compliance at home, and perhaps home-deliveries of meals and other help to follow the diet.
Conclusion (for Now)
I have a few more articles coming up on the ketogenic diet, where I will address more interesting questions on this topic.
In spite of everything I wrote, I’m not completely against this approach if it can help some people losing weight.
My problem is that many of claims made on the ketogenic diet are simply not true.
By eating a ketogenic diet, you are not learning habits that will help your health in the long-term. You are not training your taste buds to enjoy whole, simple plant-foods and you are not eating a nutrient-dense diet.
A plant-based diet appears to be much more effective in reversing Type-2 diabetes and heart disease.
Every calorie of animal food consumed is of lower nutrient-density as the same amount of calories in fruits and vegetables.
Most people will end up eating too much animal protein on this diet, even though you could technically make it vegan. This could lead to increased LDL cholesterol and risk of heart disease.
It’s important to mention that ketogenic diets are also much harder to follow than healthy plant-based diets. There are also many risks associated with these diets that simply don’t exist when using the plant-based approach that I didn’t even mention (all of which are documented):
- Digestive problems (diarrhea, constipation, nausea, vomiting, and heartburn)
- Kidney stones.
- Thinning hair.
- Low energy levels.
- Poor concentration.
- Impaired mood
- Menstrual irregularities
- Nutrient deficiency.
- Poor growth in children.
- Increased risk of infection.
Although a ketogenic diet can be relatively safe in the short-term if done properly, there are good reasons to believe that it will lead to poor health in the long-term if one consumes a significant portion of their calories from animal foods and foods high in saturated fats and cholesterol.