A Ketogenic diet is an eating approach that limits the amount of carbohydrates to induce a series of adaptations in the body. When the body is adapted, the liver produces ketones, which are water soluble fat molecules that can be used for fuel in the mitochondria.
Originally designed in 1921 to treat children with epilepsy, the ketogenic diet is being rediscovered by athletes, nutritionists and doctors as a way to lose body fat, increase endurance performance and treat diseases linked to insulin including diabetes, Alzheimer's, and traumatic brain injuries (TBI).
There is a difference between the epilepsy treatment, which is typically called “Medical Ketosis” and non-medical, nutritional ketosis (even though it can be used to treat certain diseases). Medical Ketosis diets are designed to get 80% of calories from fat, 15% of calories from protein and 5% from carbohydrates. This is strictly to treat epilepsy that will not respond to drugs. People without epilepsy will not benefit from having that many ketones in their blood.
Chasing Ketones
Most people want to be “in ketosis” for fat loss, and if they follow the Medical Ketosis macro distribution they will not achieve their body recomposition goals. People spend a lot of money on ketone monitoring kits that cost between $2 and $4 per test strip. This is not worth the money. It is more useful to think about being “low carb” rather than “in ketosis” - if you keep your carbohydrate intake to less that 25 grams NET carbs per day, you are basically guaranteed to be in nutritional ketosis. One reason people find high blood ketone levels so seductive is the enhanced cognitive focus, known as "Keto Clarity" that comes from being in the state of ketosis. You can enjoy the mental focus without measuring your blood ketone levels.
The goal is to change your default setting from “Fat Storage” to “Fat Burning” - and this is governed by insulin. Insulin is the hormone that controls how energy is stored in the cells (among other things).
Simply put, by keeping your carbohydrate intake low, your insulin stays low, and your body starts mobilizing fat for energy rather than storing it. The amount of ketone bodies in your blood don't really reflect how well your body is mobilizing fat. In fact, you might have “low” ketones because your body is burning them efficiently. When people buy “pee sticks” which measures the amount of ketones in the urine and they see there is a lot of ketones, it actually means they are not burning ketones, but producing them and excreting them. When your body is efficient at using ketones, the amount wasted (as seen in the urine) will be very low.
It is helpful to understand that ketones are a result of fat metabolism, not a goal in themselves. When you're burning fat your liver will produce ketones, ketones don't burn fat.
How to eat LOW CARB and become FAT ADAPTED
Measure your NET carbohydrate intake.
NET carbs is Total Carbohydrate minus Dietary Fiber.
For example, a cup of broccoli has about 9g of Total Carbs but 4g of Dietary Fiber, so the NET carb is 5 grams.
Some people may need more carbohydrates than 25 grams NET, depending on their daily energy requirements. For example, athletes who do Crossfit or other high intensity (HIIT) type workouts may need to increase their carb intake to 50g or higher. Triathletes may need even more. It is possible to be “fat adapted” even on over 100 grams of carbs if the body is properly trained.
Most people who are not doing a ton of HIIT level workouts can stick to the 25g NET macro.
There are a lot of macro calculators online but the one I prefer is on the KETOGAINS website.
Once you establish your lean muscle mass, your energy expenditure and your goals (fat loss, muscle gain, maintenance) you are assigned a total number of calories per day and a macro breakdown in fat/protein and carbohydrates. Set your macros in MyFitnessPal, log your daily intake and stick to it.
During the adaptation phase, you are training your body to burn fat. Increasing mitochondrial density is key to successfully transitioning. You can increase mitochondrial density by doing High Intensity Interval Training (HIIT), doing sprints repeats of around 60 seconds, Tabatas, or body weight exercises to failure (ideally a push, a pull and a squat movement - so push-ups/pull-ups/air squats to failure for several rounds). The more mitochondria you have, the more fat you will burn.
TRANSITIONING
The transition to becoming fat adapted can be tough, especially if you eat a lot of processed and sugary foods like ice cream, candy, etc. The first two weeks are typically the hardest but it gets easier after that. It is not recommended that you do a “cheat day” or even a “cheat meal” because it will make it harder to convert. I found it helpful to eat coconut oil during the first three weeks. The fat was very satiating and satisfied my cravings. I filled ice cube trays with liquid coconut oil and then put them in the fridge. I would pop one out and chew it any time I was experiencing cravings and they did the trick. Too much coconut oil can cause GI distress so make sure to take it easy.
Most people find it psychologically easier to abstain from eating unhealthy/non-keto foods than to try to eat moderate amounts. There are plenty of keto-friendly breads and desserts to keep you satisfied. Just remember that if you are eating a lot of dietary fat, you may be in ketosis, but you're not burning your stored fat. For body recomposition, this bears repeating: DIETARY FAT WILL PREVENT YOU FROM BURNING STORED FAT. So stick to your macros!
Hitting your macros is important, especially for protein and carbohydrates.
Carbohydrates are a LIMIT – stay under 25 NET grams per day
Protein is a TARGET – hit your protein target to preserve muscle, have healthy skin, organs, etc.
Fat is a LEVER – you get energy from fat and carbohydrates, if you limit carbs, you'll need the fat calories to live an active healthy life! Do not exceed your fat macros if you want to change your body composition. You might actually want to restrict fat as well as carbs for a period once you are certain you are fat adapted. This will allow you to burn more stored fat - i.e. you are in a caloric deficit, but burning your stored fat to meet your energy needs. If you find yourself lethargic, eat a little more dietary fat to see if you're just not getting enough calories to power you through your day.
Cooking
Eat as much variety of real, whole, unprocessed foods as possible.
Proteins: every kind of meat, fish and organs meats such as liver and kidney are IN
Fats: cooking/eating ghee, olive oil, avocado oil and macadamia nut oil are IN.
Do not use any other kinds of oil such as vegetable oil, canola oil, safflower oil, etc.
Carbohydrates: leafy green veggies such as kale and bok choy, cruciferous veggies like broccoli, cauliflower, and Brussels sprouts. Cooking vegetables is preferred to eating them raw. Cooking makes greens more digestible and releases more nutrients. Remember to subtract the fiber from the total carbs.
Avoid soy and it's derivatives (soybean oil is added to a lot of things). Raw nuts are good, nuts which have been coated in soybean oil and safflower oil are OK but not ideal. Choose raw (nuts) when possible.
MCT oil is a great supplement and will help put you into ketosis but be careful about how much you take at a time, it can cause GI distress.
REMEMBER: When you are reading about keto diets on the internet, they will make you think that the goal is to produce a ton of ketones and that you have a free pass to eat as much fat as you want. Ketones are a byproduct of fat metabolism, not the goal! If losing body fat is the goal, then fat metabolism is what you're after. You metabolize fat when your insulin is low and your body switches to predominantly burning fat for fuel instead of carbohydrates. You also need to eat in a slight caloric deficit so that you are burning fat to meet the the additional energy demand.
Exogenous Ketones: You can buy (expensive) exogenous ketones that will boost the amount of ketones in your blood. This might be useful during the transition, but probably unnecessary. If you are looking to boost cognitive function, exogenous ketones might also be useful although you can probably get a similar boost for much less money with MCT oil. Excess ketones can actually be converted to fat, so if you're taking exogenous ketones with the idea that it's going to help you get lean, it's probably not going to help. They might be a good appetite suppressant, but usually a well formulated diet of healthy fats and adequate protein keeps hunger to a minimum. Building more mitochondrial density is actually a better way to increase fat burning rather than supplementing with ketones.
Electrolytes: One very important supplement you will need to take are electrolytes. As insulin lowers, absorption electrolytes decreases and blood pressure can drop, Here is what is recommended by Ketogains/Lyle McDonald:
- 5000 - 7000 mg of sodium (not just salt)
- 1000 - 3,500 mg of potassium
- 300 - 500 mg of magnesium
I use Salt Stick electrolyte capsules which work great.
Useful links:
- KetoGains is a site for weightlifters AND beginners alike. They run a Boot Camp that is a great way to change your lifestyle with coaching and support.
- TuitNutrition article on measuring ketones (whole site is great but this is a must-read)
- 2 Keto Dudes are lively and informative; a great place for beginners
Disclaimer: I am not a doctor or a nutritionist. This information is based on my own experiences and research. Consult your doctor or nutritionist!