Fat Adapted Athlete: What is the ketogenic diet?

Very low carbohydrate diets have been getting more attention amongst climbers and elite athletes looking for an edge to boost performance. The one question on everyone’s mind: “Can eating a very low carbohydrate diet deliver a performance boost for a predominantly glycolytic sport like climbing?

I came across the concept of a very low carbohydrate diet (ketogenic) when I was in school taking Advanced Nutrition. I was taught that in order to maximize performance for glycolytic exercise you must consume carbohydrates prior to, during, and after exercise in order to increase fuel availability during physical activity and to boost recovery. Anyone who’s run a long distance race knows that you must eat a gel pack every 45 minutes during your race if you don’t want to hit a wall. It just makes sense. Eat some carbs if you don’t want to suck. Right? This line of thinking makes even more sense when you consider that at higher intensities of exercise, such as climbing, our muscles need a rapid fuel source (glucose) in order to continue to output a large amount of force. A bigger pool of glucose to draw from means that we can continue to push hard for longer. So why would anyone ever think that they could drastically decrease their intake of such an important metabolic fuel and expect to be better for it? This is exactly the rationale that has dominated the mainstream field of sports nutrition for the last several decades.

Now, let’s back-up really quick and make sure that everyone is on the same page. I’m a biochemist by training and so I talk like one. I can’t apologize for that, but I will try to make things as clear as possible and not try to bore you.

First, what’s a carb? A carbohydrate is any form of sugar that can be absorbed by our body and used for fuel. Glucose is the main form of carbohydrate used by most cells in our bodies, and so other sugars that are not glucose (like fructose) need to be converted into glucose before they can be added to the body’s total pool of available glucose. Glucose molecules are little cyclic rings of carbon and oxygen that can be linked together like links in a chain. The longer the chain the more complex the carbohydrate is said to be. Starch is one form of complex carbohydrate found in most grains and starchy vegetables like potatoes and squash.

The body can store glucose in a form of starch called glycogen. Individual links in the glycogen chain can be broken off when there is a need for them and consumed as fuel. When your body breaks down glucose for rapid fuel, this is called glycolysis. Glycolytic exercise is when exercise is performed at an intensity level that relies predominantly on glycolysis to supply the majority of energy required to continue that exercise.

Originally, very low carbohydrate diets were formulated as a way to help patients with epilepsy to help prevent the frequency and duration of seizures. The diet was pioneered at Mayo Clinic by Russel Wilder in the 1921 as a way to mimic the therapeutic effects of fasting without restricting calories. Oliver Owen and George Cahill were the first to show that ketone bodies were the molecules that are responsible for supporting the body during periods of starvation and low glucose availability, thus the term ketogenic diet was coined to describe Russel Wilder’s diet. Keto- meaning ketone, and genic- meaning generating. The Ketogenic diet features a very low intake of carbohydrate (<50 grams per day) , a moderate amount of protein (1.5-1.75 grams of protein per kilogram of body weight per day), and a very high fat intake (up to 90% of daily calories as fat) focusing on saturated and monounsaturated fats. You can think of this as a the Paleo diet or the Atkins diet with even less sugar and protein. The diet emphasizes very little processed food, and very high quality food.

So what is a ketone body? A ketone body is meant to describe three water soluble molecules that are generated from fat breakdown in the liver. The three compounds are ß-hydroxy-butyrate (not technically a ketone), aceto-acetate, and acetone. These start to show up in the body after the liver uses up a large portion of its glycogen, but is really a function of lower insulin levels. The exciting thing about ketones is that they can make up for the energy deficit that comes from decreasing the pool of glucose in the body. This allow the body to continue to feed organs that normally rely on blood glucose levels like the brain, protecting the body from harm during starvation.

Interest in low carbohydrate diets has taken off in recent years in the interest of boosting performance for endurance exercise. Stephen Phinney showed that elite bike racers who ditch the carbs for four weeks preserve their endurance performance but boost their rate of fat burning by almost double [1,2]. The dreaded wall is something that plagues most endurance athletes when approaching the threshold where the body runs out of glycogen and must switch over to fat burning as the predominant form of fuel in order to keep going. As athletes doing long distances get more accustomed to long events their bodies adapt to the stress of glycogen depletion by becoming better adapted to burn fat as a major fuel source during exercise. This effect is enhanced when you ditch the carbs.

I started reading about the ketogenic diet and was really swayed by the idea of the gas tank. Consuming carbs automatically gears your body to burning glucose primarily and fat as a secondary source, limiting the availability of calories in your fat fuel tank until you’ve used up the fuel in your glycogen fuel tank. Being a chemist, putting some solid numbers on the total number of calories that you can burn before you deplete your glycogen was really convincing. On average, the maximum amount of glycogen that your body can store is about 400-500 grams. Now at a caloric conversion rate of 4 kcal/gram of glycogen that gives you a reservoir of 1600-2000 kcals (food calories) available to you at your most saturated state. Now for an individual of just 7% body fat weighing 69 kg (152 lbs) they can store 4.83 kg of fat and at a conversion rate of 9 kcal/gram of fat that leaves them with a little more than 43,000 kcal. That gives you access to 20 times more fuel than you had before. Even if you keep adding to the glucose tank by eating gel packs and drinking sports drinks your body can only absorb sugar so fast before you soil yourself. At 1 gram of glucose absorbed through the intestine per minute, you’re still only adding 10% of your fuel tank back in per hour which pushes back your fatigue window an hour or two at best.

From The Art and Science of Low Carbohydrate Performance - Jeff Volek and Stephen Phinney

From The Art and Science of Low Carbohydrate Performance – Jeff Volek and Stephen Phinney

I love this quote from Volek and Phinney, “It is instructive to point out that ever since the the observation over four decades ago that low muscle glycogen was associated with fatigue, most of the progress has been focused on ways to enhance glycogen levels and carbohydrate oxidation (e.g., carbohydrate loading, use of multiple sources of sugars, etc.). Little effort has been devoted to developing methods to decrease the body’s dependence on carbohydrate during physical activity.”

Well there’s more, and it gets better! Remember that mental fatigue I talked about earlier? Well it turns out that your brain actually runs great on ketones, and most people actually report feeling sharper and more responsive when they are in a ketogenic state. Low carbohydrate diets are actually anti-inflammatory as well because burning fat as the primary fuel source limits the production of free radicals thus reducing oxidative damage throughout the body. There are implications for preventing and treating cancer as well[3].

So how does this work? You just lower your glycogen and you don’t have any performance loss even at high intensity? Well, that’s where the ketones come in. The burning of fat does two things. First, it creates more NADPH, and more FADH2 (energy equivalents) through ß-oxidation (fat burning) in the mitochondria which then help to improve the efficiency of the electron transport chain (energy production). Second, the production of ketones in the liver raises circulating plasma ketones which enter into the mitochondria much more quickly than fat does making up for lower glucose levels, preventing an energy lag from hypoglycemia. Now it should be pointed out that a higher rate of fat burning improves the efficiency of glucose burning as well, so it’s not that a fat adapted athlete doesn’t burn glucose and glycogen, but rather it uses glucose more efficiently thus sparing glycogen.

Using glucose more efficiently? Than sounds kind of cool, so what’s the catch? Well the obvious drawback is maintaining the diet. In order to get into a fat adapted state you need to be eating less than 50 grams of carbohydrate per day with an emphasis on very low-glycemic foods. When you consider that 5 apple slices (not even a whole apple) is 25 grams of sugar this severely limits your options when considering what other sources of food are allowed to fit into your budget. 50 grams is also an upper limit for someone who is continuing to do hard exercise everyday, so the reality is that a normal person would have to eat much less than 50 grams per day.

The second problem is that there is an adaptation phase or a break-in time of about two weeks before your body rewires its metabolic machinery to become more efficient at burning fat. So if you’re keen on starting the diet expect to perform poorly for that whole time. Some people mention that they feel anxiety, headache and nausea as they start to withdraw from sugar. Theses are the same symptoms that are experienced by people withdrawing from alcohol, tobacco and other drugs. Interesting…

There is a third point that is worth mentioning here, and this is honestly the most severe drawback, the ketogenic diet is diuretic, meaning that you can become dehydrated more easily. No this is not because you’re eating so much oil that you just lubricate your insides, although that sometimes happens too if you’re not careful. When your body is low on carbs your insulin levels drop and as a result your aldosterone levels also drop. Aldosterone is the hormone that tells your kidneys to hold onto sodium. That means that every time you urinate you’re losing much more salt and you will need to replace it. EVERY DAY. This is not optional, because the consequences of pissing away all of your sodium is that you will start to secrete the rest of your minerals as well, such as potassium and magnesium, so that your body can maintain the ratio of intracellular and extracellular ions. As a result, you can potentially feel really irritable and foggy, lethargic and weak, and you will start to cramp as your muscles do not have the right osmotic pressure to relax and contract properly. This is the major complaint of people who have tried the ketogenic diet.

Mineral imbalances are easy to treat but they are sometimes hard to catch until it is too late. This is especially important for women attempting the diet, because menstruation causes an additional loss of sodium, and this means that women are much more sensitive to the potential to dehydrate on this diet. Supplementation with sodium, potassium and magnesium can eliminate the majority of the flu-like symptoms that are experienced during the adaptation phase. An interesting side note here, anytime someone tells you they are experiencing “detox symptoms” from doing a cleanse, let them know that they have hyponatremia and they need to have some broth or salt water right away and they’ll feel much better.

Some concerns about the use of the ketogenic diet:
Can you get ketoacidosis from eating a ketogenic diet?

–Not unless you have type 1 diabetes. A normal person whose blood ketones are elevated above 5-6 mM will secrete insulin and shut-off or slow down the production of ketones until they come within a tolerable range. Some people claim that “mild acidosis” occurs as a result of elevating your blood ketones a small amount, but those individuals don’t fully grasp the intricacies of acid-base chemistry and the carbonate-blood buffering system that our bodies use to maintain the appropriate blood pH.

Won’t you become deficient in certain nutrients by eating only fat?
–A well-formulated diet will include many vegetables and moderate protein and a large amount of fat. There is plenty of room in the diet to obtain all of the variety that you need to meet all of your macronutrient and micronutrient needs.

Can you give yourself heart disease by eating so much fat?
–The accelerated turnover of fat means that you can eat a higher amount of fat without risk. This is a phenomenon known as the Inuit paradox. Researchers have been baffled at the low incidence of heart disease, atherosclerosis, and heart attack among native tribes, like the Inuit, who consume nearly 90% of their calories as fat. This “paradox” is only a riddle when you view it through the lens of high carbohydrate consumption. It is NOT recommended to eat a high amount of carbohydrates  AND saturated fats. You may also want to get your blood-work done and have your apoE genotype checked to make sure that your cholesterol levels don’t get out of control while on this diet. For most people cholesterol levels improve, but some people do not tolerate this diet very well. As always, consult with an open-minded doctor or certified dietician when considering a drastic diet change such as this one.

Do you have an eating disorder?
–Eating habits are such a large part of our culture and our social structure. I like to tell the joke: “You know how you can tell that someone is on the ketogenic diet? They’ll tell you.” Well it’s true, because you have to have an explanation for why you’ll never eat any of the food that anyone offers you. Eating can be a touchy subject, and eating habits more so, especially when it comes to eating disorders. There is a certain amount of risk that each individual must assume when they take on self-experimentation with a new and unknown type of diet. Some might call the ketogenic diet extreme and disordered. The reality is that this diet can be well formulated to meet both caloric and macro- and micronutrient needs. It is up to the individual to educate themselves and make sure they are putting the right foods into their body. Some people eat a strict vegan diet while eating chips and salsa for every meal and that doesn’t mean that the diet itself is unhealthy but rather the implementation is flawed. Again, consulting with someone who is qualified to give you dietary advice is an important step for ensuring that you implement the diet properly.

Now for one of the best secrets ever: How to get into ketosis without restricting carbs!

There exists a certain type of oil that is ketogenic. Many people have touted the benefits of Medium Chain Triglyceride oil as being ketogenic, but it is only mildly so. Someone was nice enough to do the research on which particular component of MCT oil is the most ketogenic one and they isolated it. It’s called caprylic acid or C8 MCT. It can be purchased on Amazon, at a very reasonable price, and it is made here in the USA. This oil will put you into mild ketosis, but if you don’t emulsify it properly it will give you the runs. So I suggest mixing the oil with some raw cacao butter, a bit of sunflower lecithin powder, and your favorite hot beverage, caffeinated or not. This is the best damn version of a bulletproof drink you can possibly make! If you use coffee it tastes just like chocolate with the cacao butter. I’m switching to decaf because of how much I like to drink of this.

Okay, now in reality this will not keep you in ketosis, and it may only give you a small boost to blood ketones. But there is some evidence to suggest that caprylic acid is active in the brain as it is one of the very few fatty acids capable of crossing the blood-brain barrier and therefore can increase neurological energy. I would highly recommend this product if you are trying to get into ketosis, or would like to use this for boosting energy output during exercise.

In the next several posts, which will definitely be much shorter – thanks for sticking with me, I will talk about:

  1. My motivation for choosing a ketogenic diet and my experience with climbing on the diet.
  2. What some of my favorite recipes are.
  3. What I supplement with and why.
  4. What my diet looks like on a typical day.
  5. Why it is that low carb diets are anti inflammatory, with a little primer on metabolism and the electron transport chain.

If you would like to hear about a particular topic or have a question, please let me know in the comments section below!

Next Post: My experience with climbing on the ketogenic diet


3 Replies to “Fat Adapted Athlete: What is the ketogenic diet?”

  1. Pingback: Fat Adapted Athlete: My experience with climbing on the ketogenic diet – The Aspiring Alpinist

    • I’ve been trying to dial in my electrolytes for a while. I have a few strategies that I use for making sure that I get enough. Daily intake of sodium while eating very-low carb should be around 5 grams a day. The best way to hit this target is to salt everything liberally, and to supplement 2 grams a day. 1 tsp of table salt should have about 2 grams of sodium, so 1 tsp of salt into 16-32 oz of water is one way of doing it. I find that salt in water is not the most palatable. Many keto-ers will drink broth or bouillon in the morning. I like the Knorr Vegetable bouillon cubes (nice basil flavor) or any one of the Better than Bouillon flavors.

      Salt supplementation should do a few things. Help you retain water, whet your thirst, and spare the loss of other electrolytes. I find that sodium supplementation by itself is not good enough for me at whetting my thirst, or helping to prevent cramps. I prefer to supplement potassium and magnesium at the same time that I supplement sodium. I find that this helps as I’m constantly struggling to drink enough water and so I loose all of my other electrolytes quite frequently. One consideration here is how much salt in how much water. If it’s too concentrated then it’ll give you the runs. A great recipe for broth is, 1 Tbsp of Beef Better than Bouillon, 2 tsp of Natural Calm, 3/4 tsp of Morton Lite salt into 1 qt of water. If you’ve discovered bulletproof coffee at this point and are looking for a non-caffeinated version, you can blend in some oil and emulsifier into this and it’s great. Also you can throw in a bunch of gelatin to supplement collagen. Boom!

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