Ketogenic Dieting: The Best Option Since Carb Loading for Athletic Endurance

As most runners, athletes, or other fitness enthusiasts can tell you: what you eat has a big impact on your training. For example, you have probably heard about the endurance benefits many runners experience from carb loading in preparation for a race. Carb loading is a great technique, and plenty of runners have used it successfully for years. However, the recent popularity of low carbohydrate diets – even among athletes – begs the question: could people experience similar endurance benefits as carb loading, but on a ketogenic or ketonic diet?

Whether you’re running outdoors, on a treadmill, or doing other workouts with or without equipment, you know you need to eat what’s right for you. This article will explore how a low-carb, ketogenic diet could benefit your training and endurance.

What is Ketosis?

The ketogenic diet is named for ketones. Ketones are your body’s by-product of consistently burning fat for fuel. Your body enters this ketogenic state, or ketosis, when there isn’t enough glycogen available from carbohydrates in your diet.

In the presence of adequate glycogen, your body will always burn that before it begins burning fat. This is why many cardio enthusiasts say you won’t begin burning fat for approximately 20 minutes into your workout – your body has to burn the glycogen first. Ketones, like glycogen, are also a fuel source for the body. Ketosis enables your body to function even without glycogen or carbohydrate fuel.

How is Ketosis Beneficial?

When your body is in ketosis, your blood sugar is regulated at a lower level. As you may already know, the higher your blood sugar, the more insulin is floating around in your body, and insulin is the fat storage hormone. So it stands to reason that lower blood sugar, and thus lower insulin, means less fat on your body. And in a state of ketosis, your body is burning fat 24/7 for everything – physical activity as well as mental.

As long as you are keeping protein at moderate levels and getting enough good-quality fat in your diet, plus plenty of fresh veggies, you should be giving your body all the nutrients it needs to function – and function well – while in ketosis.

It’s also interesting to note that many cancers feed and grow by using glucose for fuel. While normal cells have the flexibility to burn ketones instead, cancer cells don’t(1). This discovery, along with other cellular effects have led to the use of ketogenic diets to treat cancer(2), along with diabetes(3) and neurodegenerative diseases(4) such as Alzheimer’s.

What is a Ketogenic Diet?

A ketogenic diet is just what it sounds like: a way of eating that reduces carbohydrate intake enough that the body adjusts to the lack of glycogen by burning ketones for energy. As mentioned before, ketones are a byproduct of fat burning, so having them around for your body to burn is definitely great sign of fat loss.

Before you begin a ketogenic diet, it’s best to consult your doctor and do some of your own research. For those who wish to embark on this lifestyle change, knowing what to do really isn’t very difficult. Basically, a ketogenic diet is higher in healthy fats, moderate in protein, and low in carbs.

What You Might Notice

On a ketogenic diet, after reaching a state of ketosis, you will likely take notice of several benefits. These may include:

  • Decreased appetite
  • Reduced or absent sugar cravings
  • Lower cholesterol and higher HDL (good) cholesterol
  • Lower blood pressure
  • Decreased triglycerides
  • More energy and better focus
  • Reduced heartburn and dental problems
  • More stable mood

And perhaps best of all, with your glycogen stores depleted, you’ll be burning more fat than ever. That equals less fat on your body and better muscle definition.

But What About My Endurance?

Speaking of fat burning – less fat on the body is something every runner or endurance athlete wants. Fortunately, scientific studies show that a ketogenic diet can provide great benefits in your training and endurance.

For example, one study(5) at Ohio State University concluded that runners following a low-carb diet burned more than twice the fat of high-carb runners during exertion.

Another study by the American Society for Clinical Nutrition(6), found that long-term low-carbohydrate dieting shows no adverse effect on performance.

In Italy, the Journal of the International Society of Sports Nutrition(7) found no significant difference in athletic performance in a group of elite athletes who were subjected to both a ketogenic diet and their traditional high-carb diet. The athletes were given the same tests under both circumstances. However, after the ketogenic diet, the athletes showed significant improvements in body fat percentage, lean mass ratios, and more.

How to Do the Ketogenic Diet: The Breakdown

Contrary to popular perception, a ketogenic diet does not involve unlimited protein. In reality, your nutrient intake should include about 70-75% of your calories from healthy fats. Perhaps surprisingly, only 20-25% of your caloric intake should come from protein, along with 5-10% from carbs. For most people, 20-60 grams of carbohydrates is the magic range, though some people can simply stay under 100 grams for the desired effect.

The Protein Factor

Why shouldn’t you eat 3 steaks a day? Well, as fats have little or no impact on your blood sugar and insulin levels, protein actually does have some effect. If you eat too much protein, you can actually increase your blood sugar and send your body out of ketosis. And too much protein can even damage your metabolism.

What to Eat on a Ketogenic Diet

A ketogenic diet does not require special diet foods. Ketogenic foods are healthy, whole foods. Be prepared to cook more, read a few books, and even download a carb counting app to assess your nutrient ratios. To help you begin, here are some sample menus(8). They include foods such as eggs, butter, fresh vegetables, chicken, and bacon (who can argue with that?).

Just want to know what to eat and what to avoid? Here is a great list of ketogenic and non-ketogenic foods to start with. There is even a handy keto food pyramid(9).

Ketogenic or Carb Loading?

While carb-loading could provide your muscles with extra glycogen stores to get you through a race or event, your body is also able to burn ketones for energy. As the studies above have shown, a ketogenic diet could provide better fat burning benefits without a negative impact on performance.

Whether you want to burn glycogen or ketones depends on your fitness goals. If one of your primary reasons for endurance training is to burn fat, you could be doing yourself a big favor with a ketogenic approach. Your doctor, along with some trial and error, could help you decide whether a ketogenic or carb-loading approach is right for you.