While many fad diets have come and gone over the years, the ketogenic diet is still going strong. Backed by decades of research and concrete results, the keto diet is not only an amazing tool for weight loss, but it offers a wide variety of additional health benefits.
The ketogenic diet is built upon the foundation of ketosis – a metabolic process in which the body burns fat rather than carbohydrates for fuel. The by-products of this process, ketones, are responsible for the myriad benefits the ketogenic diet has been shown to provide.
But what exactly does the ketogenic diet look like, and how do you get started? Keep reading to learn the basics of the keto diet, the different versions, and how to get started.
An Overview of the Ketogenic Diet
Simply put, the ketogenic diet is a very low-carb, high-fat, moderate-protein diet. Originally developed in the 1920s for patients with epilepsy, the diet has become incredibly popular for its weight loss benefits as well as its ability to boost energy levels, improve cognitive function, and support a whole host of other bodily benefits.
Since at least 500 B.C., fasting and other dietary regimens have been used in the treatment of epilepsy and similar disorders. The first modern use of fasting for medical treatment occurred in 1911 in a study led by Parisian physicians Gulep and Marie. Though no specific details were given, they reported that 20 children and adults with epilepsy experienced a reduction in seizure severity during periods of fasting. Over the next few decades, other physicians achieved similar results through tests of their own
In 1921, an endocrinologist named Dr. Rollin Woodyatt made an important discovery – that both acetone and beta-hydroxybutyric acid were present in people following a low-carb diet and in people who were fasting. The benefits of these ketone bodies were also being studied by Dr. Wilder at the Mayo Clinic at the time. Wilder was of the opinion that long-term fasting was unsustainable but that a ketone-producing diet could provide the same benefits while being easier to maintain.
And thus, the ketogenic diet was born.
Though Dr. Wilder’s research opened the door, it was another physician at the Mayo Clinic, Dr. Peterman, who first standardized the keto diet. His version of the diet recommended 1g of protein per kilogram bodyweight, 10 to 15 grams of carbs per day, and the remaining calories from fat. Though there have been some alterations, this is very similar to the ketogenic diet as it is practiced today.
The modern ketogenic diet is still used as supportive therapy for epilepsy, but it has become increasingly popular for weight loss. In addition to increasing fat burn, the keto diet can help improve energy and mental focus, support blood sugar control, and help protect against chronic diseases like heart disease, diabetes, and cancer. It is also frequently used as a dietary tool by endurance athletes to reduce fatigue and boost performance.
Though the ketogenic diet can be customized to suit the individual’s needs, there are a few specific points that need to be hit. It should be very low in carbohydrates – no more than 5% of total daily calories – while moderate in protein and high in fat intake. As long as you stay within the recommended macronutrient ratio, there is no need to count calories. Many people also find that, once their bodies become keto-adapted, they feel less hungry and more energized.
The process of becoming keto-adapted can take anywhere from a few days to a few weeks depending on your carb intake. Keep reading to learn more about how to enter ketosis.
How Do You Enter Ketosis and How Long Does it Take?
To quickly review, ketosis is a metabolic state in which the body has adapted to burning fat for fuel instead of glucose. In a traditional diet, the body utilizes glucose as a quick source of energy, only turning to stored fats when blood glucose and glycogen stores are depleted. In a state of ketosis, the body burns fat for fuel in a process that produces ketones, a more efficient source of energy for the body and the brain.
What really happens behind the scenes as your body enters ketosis is this: your liver breaks down dietary fats into fatty acids and glycerol. This process is called beta-oxidation, and it results in the production of three ketone bodies:
These substances are then further broken down into ketone bodies, energy-rich substances that circulate throughout the body via the bloodstream. As blood sugar levels drop and ketone levels rise, the body adapts to burning fat as its primary source of fuel – this is called keto-adaptation. Once the body becomes keto-adapted, you must maintain a state of ketosis to reap the maximum benefit.
But how exactly do you enter a state of ketosis, and how long does it take?
There is no one-size-fits-all equation for ketosis – every person’s body is different, and your results will be determined by your macronutrient ratio. Generally speaking, however, the body typically stores about two days’ worth of glucose in the form of glycogen. If you consume as few carbs as possible (a maximum of 20 grams) for two days, your body may enter a state of ketosis. For most people, however, it takes a week or so of a very low-carb diet to enter ketosis.
Here are some simple tips to help you reach a state of ketosis as quickly as possible:
1. Significantly reduce your carbohydrate intake – you don’t necessarily need to cut out carbs completely, but you should stay below 30g to 35g total carbs and under 20g net carbs per day. (Net Carbs = Total Carbs - Fiber).
2. Modify your protein intake to about 15% to 20% of your daily calorie intake – eating too much protein at first could hinder your results but you’ll want to balance your protein-fat intake once you reach ketosis to maintain lean muscle mass while shedding fat.
3. Start eating more healthy fats – fat should become your primary source of energy, accounting for about 75% of your daily calorie intake.
4. Drink plenty of water to stay hydrated and to control hunger while you make the transition – keeping your body hydrated will help stave off some of the symptoms of keto flu.
5. Divide your calories evenly throughout the day to control hunger – once you reach ketosis you’ll have less hunger and fewer cravings, but you might need to exercise a little bit of extra self-control in the meantime.
6. Add some low- to moderate-intensity exercise to your day – about 20 to 30 minutes of light exercise can help burn through your glycogen stores to send your body into a state of ketosis just a little bit faster.
7. Consider fasting as an option – the ketogenic diet and intermittent fasting work very well together, so think about giving it a try (learn more in our article here).
8. Try adding exogenous ketones as a supplement – whether you’re struggling to control your carb intake or just want to reach ketosis faster, exogenous ketone supplements can help.
While you follow these steps, it is a good idea to test your ketone levels from time to time. Once you reach a state of ketosis, you can make some minor changes to your diet to make it more sustainable for the long haul to keep your body in a state of ketosis. For tips on how to test your ketone levels, refer to our article about exogenous ketones.
What Are the Different Versions?
The ketogenic diet is a very versatile diet – you can customize it to suit your goals. Historically, the ketogenic diet requires a daily carbohydrate consumption below 30g – it also focuses on “net carbs” in particular. Dietary fiber is indigestible, so you can subtract the grams of fiber from your total carbohydrate intake to find your net carbohydrate intake.
In addition to focusing on net carb intake, you should aim for a specific ratio of fat and protein. There are several versions of the ketogenic diet which require slightly different macronutrient ratios. Here is a quick overview of each plan:
Standard Keto Diet (SKD) – The most common option, the standard ketogenic diet requires a maximum of 20g to 50g net carbs per day, depending on individual needs.
Targeted Keto Diet (TKD) – This version of the diet involves eating 25g to 50g quick-digesting carbs prior to exercise with a high-protein, low-fat meal to follow the workout.
Cyclical Keto Diet (CKD) – In this diet plan, you alternate between days of ketogenic dieting and days of high carb intake (called carb-loading).
For the most part, the standard ketogenic diet is the simplest to follow and the easiest to stick to. The ideal macronutrient ratio for this version of the diet is 5% carbohydrates (no more than 50g net carbs), 15 % to 20% protein, and 70% to 75% fat. The targeted ketogenic diet is very similar, except for the fact that you time your carb intake to coincide with your workouts. You should stay within the 25g to 50g net carb rule but consume those carbs 30 to 60 minutes before exercise.
The cyclical ketogenic diet is a little bit different. For the most part, this version of the diet is popular among athletes and bodybuilders who want to maximize their fat burn without losing any muscle mass. The CKD involves switching back and forth between days of ketogenic dieting (under 50g net carbs) and days of carbohydrate loading. When you are carb loading, you’ll consume between 450g and 600g carbohydrates over a three- to five-day period.
In addition to these three versions, there are a few other modifications of the ketogenic diet to consider. One of them is the restricted keto diet – this is simply the ketogenic diet combined with calorie restriction, and it is intended for therapeutic use. There are also some proponents of a high-protein ketogenic diet, but the general consensus is that eating too much protein can be detrimental to the ketogenic diet. If you consume too much protein, your body has the option of breaking it down and converting the amino acids into glucose that can then be used for energy – this defeats the entire purpose of the ketogenic diet. The keto diet should be high in fat but only moderate in protein intake.
The Keto Diet Food List
Though the ketogenic diet is less restrictive than many diets, you do need to be careful about what you are and are not eating. Remember, the keto diet is high in fat, moderate in protein, and low in carbs. Keep in mind as well that the majority of your fat intake should come from healthy fats, and the carbs you do consume should ideally come from whole foods like fruits and vegetables.
So, what kind of foods can you eat on the ketogenic diet? Here is a quick list:
Healthy Fats – grass-fed butter, olive oil, coconut oil, palm oil, avocado, some nuts and seeds
These lists are by no means complete, but they should give you a good idea what foods you can and cannot eat on the ketogenic diet. Just do your best to stay within your macronutrient ratios while also adhering to these lists and you should have no trouble with the ketogenic diet.
A Day in the Keto Life
The beauty of the ketogenic diet is that you do not have to restrict yourself to low-calorie foods. While you should certainly moderate your carbohydrate intake, there are plenty of delicious food options available – just take another look at the food list provided above!
Though the ketogenic diet is certainly not one of the most restrictive or complicated diets out there, it does take some getting used to. To give you an idea what this diet might look like on a daily basis, here is a sample meal plan for a day in the life of the keto diet:
Option 1: Spinach, mushroom, and mozzarella omelet plus coffee with KnowBrainer (creamer that contains MCT oil and Organic Grassfed Butter)
Option 2: Smoothie made with almond or coconut milk, a handful of blueberries and walnuts
Option 3: Bacon with fried eggs plus full-fat yogurt (low carb) with toasted nuts
Option 1: Mixed greens with grilled chicken breast, sliced avocado, and oil with vinegar
Option 2: Chilled avocado soup made with fresh avocado, chicken broth, and lemon juice
Option 3: Spinach salad with hardboiled egg, crumbled bacon, and feta cheese
Option 1: Grilled fillet of salmon with steamed broccoli or cauliflower rice
Option 2: Seared sirloin steak (grass-fed) with sautéed kale or spinach
Option 3: Ground beef with low-carb tomato sauce and spiralized zucchini noodles
Option 1: Roll-ups with sliced ham, lettuce, tomato, and avocado
Option 2: Cream cheese spread on cucumber slices or with celery sticks
Option 3: Homemade guacamole with sliced zucchini, cucumber, or celery