The ketogenic diet, or the “keto diet”, is a low-carbohydrate, high-fat diet that has gained popularity in recent years.
As we will cover more in depth in the following sections, the ketogenic diet was developed as a nutrition intervention for epilepsy.
However, it now has become increasingly popular in the fitness and nutrition industry, mainly because of its potential health and weight loss benefits. But this has also come with a lot of controversy due to possible health risks as well.
In this blog post, we will explore the origins of the ketogenic diet, its benefits and drawbacks, its potential impact on exercise performance, how to follow the diet, and we will answer some frequently asked questions.
The Ketogenic Diet – The Origins
The Origins and Definition
The origins of the ketogenic diet can be traced back to the early 1900s when it was developed as a therapeutic intervention for epilepsy.
In fact, the diet was initially introduced by Dr. Russell Wilder at the Mayo Clinic in 1921, and it was based on the observation that fasting can reduce seizure activity in some people with epilepsy (1).
The classic ketogenic diet is a very-low-carbohydrate and high-fat diet, and it also restricts energy content (lower overall calories than a person would normally consume).
Normally, the carbohydrate (CHO) intake is reduced to less than 30 grams per day.
However, some studies suggest that it can vary between 20 to 50 grams per day (2).
To give you an idea, a medium banana has 27 grams of CHO, and one medium zucchini has 6 grams of CHO.
The Findings
Wilder and his colleagues found that this type of diet could mimic the metabolic state of fasting and lead to a reduction in seizure frequency by changing the way the body uses energy.
Normally, the body uses glucose as a source of energy. Glucose comes from carbohydrates, but since these are heavily limited in this diet, the body uses fat as a source of energy, primarily through the breakdown of fatty acids in the liver.
From these fatty acids, the liver produces something called ketone bodies, and most organs can use these ketones as an alternative source of energy. This state is called ketosis (1).
The diet was commonly employed but lost favor once medications for epilepsy became available.
Types of Ketogenic Diets
Now that we covered the basics, let’s discuss the slight differences between three main types of ketogenic diets.
The Classic Ketogenic Diet
This was the diet mentioned in the previous section – the one proposed by Dr. Wilder.
This diet is reduced in calories, and the macronutrient breakdown for this diet is (3):
- 90% of calories from fat
- 6% from protein
- 4% from CHO
For most people, this is a very restrictive diet, especially in protein and CHO. It is not recommended for the average population – remember, it’s entire purpose was to manage childhood seizures.
The High-Protein Keto Diet (HPKD)
The HPKD is a keto diet commonly found in popular ketogenic resources (5). This diet’s breakdown is:
- 60% fat
- 35% protein
- 5% CHO
The Standard Keto Diet (SKD)
This is the ketogenic diet usually used by the “average” person, and not in a clinical setting. For that reason, there is not one single “standard”, but popular resources about the keto diet indicate that the standard macronutrient breakdown is (6):
- 70-80% fat
- 5-10% carbohydrate
- 10-20% protein
If you follow a keto diet already, or if you are interested in following one, this is most likely the breakdown you would be following.
Pros and Cons of the Ketogenic Diet
Now that we discussed the types of keto diet, let’s cover the pros and cons.
Benefits
Weight Loss
It is important to note that weight loss does not equal fat loss. We can lose weight by losing muscle tissue, connective tissue, or water as well.
When starting a ketogenic diet, it is common to lose a lot of weight at the beginning. Usually, this is caused by water loss.
When we eat carbohydrates, they are broken down into glucose, which is stored mainly in our muscles and liver as glycogen.
On average, each gram of glycogen found in muscle is stored with at around 3 grams of water (7). And on average, a person can have ~600 grams of glycogen stored (8). So 600 grams of glycogen could be storing around ~4 lbs. of water alone.
However, ketogenic diets have also been linked to fat loss. The main factor behind it (and the one supported with the most evidence) is appetite suppression (2).
Without getting into too much detail, fat loss is achieved when we are on a calorie deficit – consuming less calories than the ones we “burn”.
So, a ketogenic diet can help you reduce your calorie intake by (2):
- Reduced appetite due to higher satiety effect of proteins
- Effects on appetite control hormones
Improved Blood Sugar Control
The ketogenic diet has been shown to improve insulin sensitivity and blood sugar control, making it a good option for people with type 2 diabetes.
However, keep in mind that the number one factor in improving insulin sensitivity for type 2 diabetes is weight loss, which can be achieved with any diet as long as there is a calorie deficit (9).
Neurological and Autoimmune Diseases
Ketogenic diets can improve the cognitive abilities and quality of life of patients ranging from mild to severe Alzheimer’s disease (10). However, more research needs to be conducted.
Drawbacks
Keto Flu
When first starting the ketogenic diet, some people experience symptoms such as headaches, fatigue, and nausea, which are collectively referred to as “keto flu.” This is likely due to the body adjusting to the new metabolic state.
Difficulty with Adherence
The ketogenic diet can be difficult to adhere to, particularly for those who are used to consuming high-carbohydrate foods. The diet also limits food choices.
Nutrient Deficiencies
Because the ketogenic diet limits certain food groups, it can lead to nutrient deficiencies if not carefully planned. It is important to ensure adequate nutrient intake through supplements and careful meal planning.
Muscle Loss in Resistance Training
The research about this topic is very complex and science-heavy, so we will simplify the findings. If you want to read the article, you can check reference 11.
For most gym goers, this is the conclusion: you can absolutely build muscle and get stronger in a ketogenic diet. However, if you are an intense bodybuilder or powerlifter, you could not get as optimally muscular or strong.
When you are training at those high levels, it involves the anaerobic system, and carbohydrates are usually needed to achieve maximum performance in these sports (especially when training close to failure).
How to Follow the Ketogenic Diet
Calculate your Macronutrient
You can look online for a “keto macronutrient calculator” to get an idea of how many grams of each macronutrient you should be consuming each day. However, it is strongly recommended to work with a dietitian or healthcare professional.
Plan and Prepare your Meals
Here you can find an article with keto food list ideas. Always keep in mind that if you do consume too much protein instead of fat, you will likely not be in ketosis.
Also prepare your meals in advance to make sure you always have healthy, keto-friendly meals on hand.
Dining Out
Eating out can be challenging when you’re following a ketogenic diet. Look for keto-friendly options like grilled meats or salads, and don’t be afraid to ask your server to make modifications.
Consider Supplements
Talk to your healthcare provider or a registered dietitian to determine if you need them and identify which supplements may be right for you.
FAQ
Is it safe to follow a ketogenic diet long-term?
First, it is important to note that a ketogenic diet may not be safe for some people, even in the short term. This is why it is important not to start this diet alone without any supervision.
Unfortunately, long-term research on the keto diet is limited.
Can I follow a vegetarian or vegan ketogenic diet?
A vegetarian diet is possible, in theory. Here is an article listing some vegetarian, keto-friendly foods. However, this would require even more close supervision and it may be difficult to adhere to it.
A vegan keto diet is likely not possible.
Can I drink alcohol on a ketogenic diet?
You can drink alcohol and still be on ketosis. As always, if you do decide to drink, drink in moderation and every so often. Here is an article detailing the grams of carbohydrates in common alcoholic beverages.
How do I know if I’m in ketosis?
The best way is to measure ketone levels directly, but there are also some symptoms that could help you know if you are in ketosis. Check this article for more information.
Conclusion
The ketogenic diet is a high fat, moderate protein, and low carbohydrate diet. It can be helpful for those trying to lose weight and it can even have therapeutic effects.
However, as with any diet, there are some drawbacks as well: such as difficulty adhering to it, and possibly not being the most optimal diet for advanced bodybuilders or powerlifters.
This post was written by Irene Mejia, RD and Sports Nutrition Specialist.
References:
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3826507/
3. https://onlinelibrary.wiley.com/doi/10.1111/j.1528-1167.2005.00282.x
4. https://pubmed.ncbi.nlm.nih.gov/24386671/
5. https://www.health.com/weight-loss/keto-diet-types
8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019055/
9. https://health.clevelandclinic.org/diabetes-and-weight-loss-what-you-need-to-know/