The ketogenic diet is a high-fat, low carbohydrate eating approach that mimics the effects of fasting. In fact, during the 1920’s, researchers evaluated the effects of fasting or spending significant portions of time without consuming food on epileptic seizures. What they found was that fasting placed subjects into a state of ketosis or metabolic state where the body runs on fat and molecules known as ketones. In response, the seizures diminished (1).
Other researchers realized that fasting for long durations isn’t sustainable, so they began to theorize different ways to achieve the same effect, without fasting. The result was the birth of the ketogenic diet; a diet focused on eliminating carbohydrates and increasing fat consumption simultaneously (2).
Fast forward 90 years or so and the ketogenic diet is one of the most popular methods for weight loss and improving health. But you need to know how to use it correctly to excel.
What Is The Ketogenic Diet?
The ketogenic diet is a low carb approach to eating which was initially developed for people suffering from epileptic seizures. Since then, researchers have revealed that the ketogenic diet provides a host of other health benefits.
When carbohydrates comprise a majority of our diet, our bodies rely on glucose (sugar) for energy production. However, switching to a fat-based diet while eliminating carbohydrates results in massive changes throughout the body. Most notably, the body transitions from using glucose (sugar) as a primary fuel source to relying almost entirely on fat and ketones, placing you in a state of ketosis.
Once in this state of ketosis, research suggests that the benefits are wide-reaching ranging from weight and fat loss to brain protection and even improving cholesterol status. These benefits make the ketogenic diet an attractive option for many (3, 4, 5).
Know that being in ketosis is the backbone of the ketogenic diet and is responsible for many of the positive benefits of the diet. As you’ll soon understand, there are guidelines that you’ll need to follow to ensure that you’re effectively getting into and staying in ketosis.
What Is Ketosis?
Ketosis is the metabolic state that occurs when you remove carbohydrates from your diet almost entirely. During this time, the body begins up-regulating fat metabolism, making fat the primary source of energy.
When you’re not in ketosis, fat metabolism is pretty straightforward. Fat molecules enter cells known as mitochondria and undergo a process known as beta-oxidation where the molecules are broken down and move on in the energy production process.
On a ketogenic diet though, the process is a bit different. Since the body switches to using fat almost entirely, the liver, (where beta-oxidation occurs) cannot keep up with the amount of fat being metabolized. The result is an accumulation of acetyl-CoA, which is a byproduct of fat metabolism.
These accumulating acetyl-CoA molecules then begin to condense and combine to form other molecules known as ketone bodies. In fact, this process leads to the generation of three different ketones including acetoacetate, Beta-Hydroxybutyrate (BHB) and acetone, which are widely regarded as the reasons the ketogenic diet is so beneficial. But this also comes with an issue: the liver can’t use ketones.
Unfortunately, the liver doesn’t have the necessary enzymes to break down and use ketones, so they need to be shuttled elsewhere. Once synthesized, these molecules enter circulation where they can act on other tissues of the body to provide energy. Once the level of these ketones reaches significance in the blood and becomes a primary source of energy, this is when you’re considered to be a state of ketosis.
The process of transitioning into ketosis looks like this:
The process of getting into ketosis is pretty straightforward and relies almost entirely on eliminating carbs from your diet.
Why Consider A Ketogenic Diet?
Understanding how the process of ketosis works is imperative for success, but it also helps to know why you’d even consider this diet in the first place. In addition to changing your body’s fuel source to fat, the ketogenic diet also offers an array of different benefits you might not receive with other dieting methods.
The most common benefits of ketosis include:
Keto Helps With Weight & Fat Loss
Research suggests that using a ketogenic diet in combination with calorie restriction is a useful tool for weight and fat loss. But this isn’t entirely surprising. When you’re in ketosis, your body is already preferentially metabolizing fat. This means the weight you do lose is likely to come from fat mass (3).
Keto Improves Your Cholesterol
Contrary to popular belief, eating a fat-centric diet improves cholesterol levels. In fact, research shows that eating a ketogenic diet increases HDL cholesterol, otherwise known as “good cholesterol,” while LDL, the type responsible for arterial plaques, is reduced (5, 6).
Keto Protects The Brain
Emerging research suggests that ketones help to protect the brain. In fact, evidence indicates that ketosis improves memory for those who have Alzheimer’s disease and reduces symptoms related to Parkinson’s, suggesting a protective effect of the diet (4, 7, 8).
Keto Reduces Inflammation
Inflammation is a necessary and appropriate response to threats, but chronic and excessive inflammation is a sign of a malfunctioning immune system. Research on the ketogenic diet suggests that removing carbohydrates and focusing on fat often leads to reductions of different markers of inflammation making it an attractive option for those suffering (9, 10, 11).
Keto Improves Memory & Cognition
Fortunately, the brain is entirely adept at functioning on ketones. In fact, it might prefer them. Recent studies indicate that the use of a ketogenic diet significantly improves cognitive function and it seems there is also a correlation between ketone levels. Fundamentally, the cognitive benefits of ketosis develop as you progress through the diet and become more keto-adapted (12).
How To Practice The Ketogenic Diet
The ketogenic diet is entirely different from other methods of eating since you’ll drastically reduce carb intake and significantly increase the amount of fat you eat.
In the medical world, this means consuming anywhere from 70-80% of your total calories from fat, while keeping protein to around 20% and carbs below 5%. However, in the real world, it’s not always so cut and dry.
Getting 70% of your calories from fat isn’t always the most natural venture, and fortunately not always a requirement. As individuals, we all have different bodies, which come in different shapes and sizes. As a result, our bodies process nutrients differently.
For example, a large person might be able to consume upwards of 100 grams of carbohydrate and stay in ketosis while a smaller person might get kicked out of ketosis after consuming 30 grams. The requirements of getting into this state of ketosis will vary from one person to the next, and there’s no global approach. Remember that getting into ketosis is not an exact science. Each person will respond differently to each approach and will require adjustment.
When practicing the ketogenic diet, half of the equation is to limit the number of carbs you consume. Traditionally, carbs should be the least consumed macronutrient out of the three, making up around 5-10% of your total calories.
This recommendation can vary widely, however. Some people can consume more carbs than others and remain in ketosis while others can’t. Being able to do so will require a bit of self-experimentation.
While most diets recommend a high protein intake, caution must be taken while in ketosis. If protein intake is too high, the body can convert that protein into glucose through a process known as gluconeogenesis.
When this occurs, it’s unlikely that you’ll remain in ketosis. A good starting point is to maintain around 20-25% of your total calories from protein and adjust based on how you respond.
Since carbohydrate and protein intake will be limited, fat intake will become a primary source of fuel. Based on the number of carbs and protein that you can consume, the remainder of your calories should come from fat.
Test For Ketosis
When you’re practicing a ketogenic diet, you need to regularly check your ketone levels to ensure that you’re in the state of ketosis. If you aren’t in ketosis, it’s unlikely that you’re receiving all, if any of the health benefits.
Currently, there are two primary methods for testing ketosis with ease.
Urine Ketone Strips
Urine ketone strips are the most accessible option for testing ketone levels. Traditionally, these strips are used for people with diabetes to test for ketoacidosis, but fortunately, they work just as well for testing ketone levels of healthy individuals.
When using this method, it’s recommended that you test multiple times per day, as ketone strips can sometimes be inaccurate. Although urine-testing strips are the least accurate out of the two methods, it is the most economical.
Blood analysis is a bit more intrusive, but a far more accurate method of testing ketones. Whereas urine strips tell you how many ketones you’re excreting through urine, blood analysis gives you an image of what’s going on in the blood at that exact moment, which provides you with greater control over your ketosis journey.
Know that this method does come with stipulations, though. In addition to a steeper price point, this method also requires a blood draw for each test, similar to how people with diabetes monitor blood sugar. This is something to consider ahead of time.
Fortunately, each of these methods will be suitable for testing ketone levels. Although, if you’re in need of higher accuracy, using blood testing is the gold standard.
What To Eat On A Ketogenic Diet
Could you have ever imagined that bacon might be considered an acceptable food while dieting?
Since the ketogenic diet is rooted in restricting carbs and increasing fat, you’ll need to focus on foods that manage to do both. Some of the most popular ketogenic options include:
- Healthy Oils like Avocado, Olive, and Coconut Oil
- Meats (Grass-fed if possible) & Jerky
- Fatty Fish like Tuna and Salmon
- Leafy & Cruciferous Vegetables
- Butter / Heavy Cream
- Coffee (Black)
- Nuts & Seeds
Mostly, you should focus on natural foods that provide high amounts of healthy fats, while moderating your protein intake. You also want to opt for foods that have a relatively low number of carbohydrates; otherwise, you risk being kicked out of ketosis.
What Foods To Avoid On A Ketogenic Diet
The catch of being able to eat foods like bacon and avocado all the time is that you’ll need to avoid foods rich in carbohydrates continually. Otherwise, you risk being kicked out of ketosis, defeating the whole point of the diet. The most popular foods to avoid includes:
- All Sugars
- All Grains (rice, oats, bread, pasta, pizza, etc.)
- High Carb Dairy (Milk)
- Most Fruits
- Most Processed Foods (candy, cereal, crackers, etc.)
Keep in mind that some other foods might contain significant amounts of carbohydrates in disguise. Foods like condiments and dressings may have deceptively high amounts of carbs, and “sugar-free” options are often loaded with sugar alcohols, which might make staying in ketosis difficult. It’s recommended that you regularly check food labels to avoid accidentally consuming large amounts of carbs.
Understanding The Transition Period
Most people talk up the benefits of the ketogenic diet but often forget to mention that there is a period when transitioning from a carb-centric diet where you might not feel great. This transition is often labeled as the “keto-flu” as many of the side effects mimic those associated with the flu. This isn’t to scare you, but rather provide you with notice that it happens. Preparing yourself ahead of time is the best defense you can have.
Since your body has been functioning on glucose for most of your life, radically reducing carbs and increasing fat at once can cause issues, since the body doesn’t know how to respond. When this happens, you might end up experiencing brain fog, migraines, nausea, fatigue, weakness and a host of other issues for a short period while you transition.
Fortunately, some practices can reduce the severity of symptoms:
Rather than eliminating carbs and dramatically increasing fat overnight, a smarter approach is to transition gradually. Start by reducing carbohydrates by 25% per day and adjust accordingly. At the same time, try incorporating high-fat food options into your diet.
Doing so makes the process much more comfortable and usually reduces the severity of symptoms associated with the transition.
When you severely restrict carbs, one response of the body is to increase excretion of water, leading to dehydration, which can cause many of the side effects associated with keto-flu. Take special care to remain hydrated during the transition period as well as after you’ve successfully transitioned.
An unfortunate side effect of increased water excretion is that you also lose electrolytes like sodium and potassium, which can contribute to the flu. Try using an electrolyte supplement alongside your increased water consumption (13).
During the transition period, it might seem difficult to exercise but doing so is recommended. Exercise can increase levels of ketones in the blood, especially if you’re restricting carbs. Doing so might reduce the severity of symptoms in addition to speeding up your transition (14).
The ketogenic diet is a dieting method focused on increasing the consumption of dietary fat while severely restricting carbohydrates. When you drastically restrict carbs, this forces your body into a state of fat burning, known as ketosis.
Amazingly, ketosis provides a host of positive health benefits ranging from effortless weight loss to potentially protecting the brain from threats like Alzheimer’s and Parkinson’s disease.
Know that the ketogenic diet is unique from other forms and requires a particular level of attention, such as regularly testing your blood and consistently checking food labels. Not to mention, there is a transition period that comes with its own requirements, but fortunately, this is short lived.
Once you’ve made it past the transition period, you’ll be in a perfect position to thrive on the ketogenic diet.
- Wheless, J. W. (2008). History of the ketogenic diet. Epilepsia, 49(s8), 3-5.
- Woodyatt, R. T. (1921). Objects and methods of diet adjustment in diabetes. Trans Assn Amer Phys, 36, 269-292.
- Johnstone, A. M., Horgan, G. W., Murison, S. D., Bremner, D. M., & Lobley, G. E. (2008). Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum–. The American journal of clinical nutrition, 87(1), 44-55.
- Gasior, M., Rogawski, M. A., & Hartman, A. L. (2006). Neuroprotective and disease-modifying effects of the ketogenic diet. Behavioral Pharmacology, 17(5-6), 431.
- Sharman, M. J., Kraemer, W. J., Love, D. M., Avery, N. G., Gómez, A. L., Scheett, T. P., & Volek, J. S. (2002). A ketogenic diet favorably affects serum biomarkers for cardiovascular disease in normal-weight men. The Journal of nutrition, 132(7), 1879-1885.
- Dashti, H. M., Mathew, T. C., Khadada, M., Al-Mousawi, M., Talib, H., Asfar, S. K., … & Al-Zaid, N. S. (2007). Beneficial effects of ketogenic diet in obese diabetic subjects. Molecular and cellular biochemistry, 302(1-2), 249-256.
- Reger, M. A., Henderson, S. T., Hale, C., Cholerton, B., Baker, L. D., Watson, G. S., … & Craft, S. (2004). Effects of β-hydroxybutyrate on cognition in memory-impaired adults. Neurobiology of aging, 25(3), 311-314.
- Vanitallie, T. B., Nonas, C., Di Rocco, A., Boyar, K., Hyams, K., & Heymsfield, S. B. (2005). Treatment of Parkinson disease with diet-induced hyperketonemia: a feasibility study. Neurology, 64(4), 728-730.
- Hao, J., Liu, R., Turner, G., Shi, F. D., & Rho, J. M. (2012). Inflammation-mediated memory dysfunction and effects of a ketogenic diet in a murine model of multiple sclerosis. PloS one, 7(5), e35476.
- Gasior, M., Rogawski, M. A., & Hartman, A. L. (2006). Neuroprotective and disease-modifying effects of the ketogenic diet. Behavioral Pharmacology, 17(5-6), 431.
- Yang, X., & Cheng, B. (2010). Neuroprotective and anti-inflammatory activities of ketogenic diet on MPTP-induced neurotoxicity. Journal of molecular neuroscience, 42(2), 145-153.
- Krikorian, R., Shidler, M. D., Dangelo, K., Couch, S. C., Benoit, S. C., & Clegg, D. J. (2012). Dietary ketosis enhances memory in mild cognitive impairment. Neurobiology of aging, 33(2), 425-e19.
- Chatterjee, R., Yeh, H. C., Edelman, D., & Brancati, F. (2011). Potassium and risk of type 2 diabetes. Expert review of endocrinology & metabolism, 6(5), 665-672.
- Langfort, J., Pilis, W., Zarzeczny, R., Nazar, K., & Kaciuba-Uściłko, H. (1996). Effect of low-carbohydrate-ketogenic diet on metabolic and hormonal responses to graded exercise in men. Journal of physiology and pharmacology: an official journal of the Polish Physiological Society, 47(2), 361-371.