Why You Should Consider the Keto Diet for Cardio

What is the keto diet?

The keto diet is a type of low carb diet that focus on getting more calories from proteins and fat and less from carbs. When you are eating less carbs, eventually your body starts to run out of sugars to fuel you and must rely on fat as your main source of energy.^[1]WebMD – What’s a Ketogenic Diet? As a runner, you can take advantage of this fact and use the keto diet for cardio benefits.

Keto and Cardio Don’t Go Together?

One of the biggest knocks against the keto diet for cardio is that it is not good for runners.

In fact, according to James Fell, a runner, columnists, and author of Lose it Right, he says that he would go “on the record saying Keto is terrible for any serious athlete” and that . “Fat is low combustion fuel. When you are engaged in high-intensity activity, you need rapid access to quick-burning fuel. When you have carbs in your system, you get it.”^[2]Podisum Runner – Is the Keto Diet Right for Runners?

He adds that “Fat simply burns too slow, so it’s like trying to suck fuel through a straw and it holds you back from a maximum intensity effort.”

However, according to Brett Osborn, neurosurgeon and nutrition adviser to nutrition and supplement site BPI Sports, he thinks that the keto diet is actually a great one for runners and endurance athletes. In fact, it is a “myth” that we need to “carb” up before a run.

In order to see the best benefits of the keto diet for cardio, you need to already be in ketosis before your race. In fact, this is a process that takes time, and one you should start months ahead of your planned race.

Don’t feel bad if you start out by not feeling good

Another big knock against the keto diet is that many people don’t feel so good when starting out, especially when they are mixing working out with it.

However, you should not be alarmed. This is part of the process. In fact, it is not uncommon to experience the “keto flu”, where you feel like very sick due to your body adjusting to the new diet.

According to Menacham Brodie, C.S.C.S., C.N.C., head coach of Human Vortex Training, this is completely normal as “Your body is using a different pathway to unlock the energy it needs to meet exercise demands.”

As such, in your first few weeks, make sure to focus on easing yourself into your new diet and workout plan. You need to balance your food hungry and cravings with how much you are working out.

In addition, according to Brodie, “as a general rule, high-intensity workouts with repeated hard efforts tend not to go well with the keto diet, as your body is using fat for its fuel source. In order to get the energy it needs, the body has to break down fats as opposed to pulling from carbs, and that takes more time.”^[3]Greatist – Working Out on the Keto Diet Can Be Weird—Here’s What Works

Health Benefits of Exercise in Ketosis

While it might seem that ketosis wouldn’t be beneficial for exercise long term, it has in fact been proven to have several benefits including:^[4]perfect keto – How to Exercise When You’re in Ketosis

Better able to replenish muscle glycogen after working out
Improved endurance over long periods of aerobic exercises
Maintenance of blood glucose levels while working out ^[5]NCBI – Capacity for moderate exercise in obese subjects after adaptation to a hypocaloric, ketogenic diet
Better overall performance in all forms of exercise over time^[6]NCBI – Effects of a low carbohydrate weight loss diet on exercise capacity and tolerance in obese subjects
You hold less water when you are on a low-carb diet. With less bloating it can help you run faster.^[7]Dave Asprey – TAKE YOUR TRAINING TO THE NEXT LEVEL WITH KETOSIS

Other Benefits of Keto

In addition to numerous benefits that the keto diet has for training, it also has several benefits in your overall health including:

Increased fat burning over the long haul^[8]NCBI – Metabolic characteristics of keto-adapted ultra-endurance runners
Reduction in carbs help testosterone levels increase, which in turn help you burn more fat
Increased overall energy levels

You May Experience Performance Dips

One of the big downfalls of the keto diet is that you will probably find it tougher to perform high intensity exercises.

This is because high intensity exercises usually tend to be ones where you have to have bursts of energy. This type of movement requires carbs which are stored as glycogen in your muscles. The muscles then can use this fuel right away when needed.

However, since the keto diet focuses on using fat as your main source of energy, it takes a bit longer to access this fuel.

As such, if you are performing high intensity activities such as sprinting, lifting weights, or quick reaction sports, you probably won’t see as big of a benefit by adopting a keto diet.

However, if you are focused on lower intensity aerobic activities such as 5k, 10k, half marathon, marathon, or even longer races, you will see a much bigger performance help.^[9]Everyday Health – 6 Things You Need to Know About Exercising on the Keto Diet

The Keto Diet for Athletes

When doing the keto diet for cardio is it first and foremost important to get down your fat, protein, and carb macros.

The most important macro that you should start with is protein.

This is what helps stimulate muscle growth, promote calorie burning, and protect against muscle loss.

After proteins, as an athlete and runner, this is where you might stray slightly from the “standard” keto diet.

A couple main modifications include:

Targeted Keto Diet – this is exactly the same as a regular keto diet; however, in addition to your regular carb intake each day, you take an additional 20 to 50 grams of carbs 30 minutes to 1 hour before you work out. If you are really worried about gaining weight, you can cut the extra calories out of your fatmacros.
Cyclical Keto Diet – follow the regular keto diet for 5 to 6 days each week. The other 1 to 2 days are your high carb days where you refill your liver and muscle glycogen stores.^[10]Thrive/Strive – A Simple Guide to Exercising While on the Keto Diet

A few other things to consider when on the keto diet for cardio and athletic performance are:

Make sure to get enough electrolytes (magnesium, potassium, and sodium) especially when you are sweating a lot
It is important to remember that each person is different and that you will need to experiment with these diets yourself to find out what works the best for you.^[11]Paleo Leap – KETO AND EXERCISE A LOOK AT THE RESEARCH

What should you eat after a run?

Just because you are on a diet, doesn’t mean that you shouldn’t be eating.

In fact, on the keto diet, post workout meals are very important. Your body needs complex carbs, proteins, and fat in order to help repair your muscles and replenish your energy.

However, while on a keto diet, it is important to understand the proper amount of macros you should be getting.

According to Molly Devine, RD, LDN, and founder of Eat Your Keto, “There is only a certain amount of protein that can be absorbed and used by the body, and any amount beyond that gets converted to glucose to be stored as glycogen or fat”.^[12]Popsugar – The Keto Diet Won’t Sabotage Your Gains as Long as You Eat This After a Workout

However, rather than focusing on just eating proteins after your run, you should focus on eating a healthy balanced meal.

On a keto diet this means:

3 to 4 oz of protein (chicken, salmon, or steak)
25 to 25 grams of healthy fat (grass-fed butter, coconut oil, ect.)
Max of 10 grams of carbs from non-starchy vegetables (squash, mushrooms, broccoli, and leafy greens)

Final Words

The keto diet was originally envisioned as an easy way to get more energy and burn more fat. Many people wrote it off as a good diet for cardio athletes.

However, with the proper modifications and paying attention to your body, the keto diet can be a great benefit for your cardio, helping you have that feeling of unlimited energy the next time you are out for a run.

If you would like to learn more about the keto diet and dieting as a runner in general, check out:

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