Many of you have concerns about exercising on Keto – why wouldn’t you?
We have been told for years that bodies and brains fuel of choice ~ is carbs.
This is another one of those diet-subjects about which we have been badly misinformed.
Not only are carbs unnecessary to exercising, but for most of us, it’s better to exercise in Ketosis.
Still, I remember my thought process before I started Keto. When I went for a run, I always had some candy before I went just to make sure I didn’t have a heart attack or a stroke. (Because this is what I had been told to do in high school track, on the ski team and in the ARMY.)
When I started Keto I was afraid of working out too hard the whole time because letting go of the “carb-is-the-best-fuel” idea was difficult. It had been drilled into my head.
Since I have done all of this research and I have been doing exercise on Keto for over three years, I can tell it is healthy to exercise on Keto, and fat is the best fuel.
Done correctly Keto is a safe and healthy lifestyle.
You don’t need to eat carbs to exercise
Obviously, your muscles need fuel to move.
We crave lots of different kinds of food for lots of different nutritional reasons.
But when you begin Keto it’s important to understand the three Main types of fuel that your body uses for fuel…
There are three Macro’s (Macro-nutrients);
Carbs, protein, and Fat.
There are all sorts of micro-nutrients too – Vitamins, minerals, essential fatty acids, amino acids and so on.
All of these have important functions, but they are not used for energy.
For fueling your muscles there are only two choices.
Either you are a sugar/carb burner and your muscles burn glycogen or, you are a fat burner and your muscles burn Ketones.
No matter what kind of exercise you’re doing, Ketones work just fine for fuel.
Whether it’s cardio, weightlifting, yoga or just going for a nice walk with your dog you can use Ketones for fuel.
I regularly run more than 4 miles, I walk at least 2 miles everyday, I do yoga, I lift weights, and I am an avid skier.
I have no problem doing any of these things while in Ketosis.
If you worry about the safety of Keto, check out this post on Ketosis and Safety.
Exercise on Keto & Your Brain
It’s true that your muscles don’t need carbs. In fact your muscles and organs tend to run better on ketones than on glycogen.
But what about your brain?
Your brain is like the rest of your body mostly… but not quite the same.
If you are to remove all the carbs from your diet (either by fasting or eating only fat and protein), your body and brain will first burn up all the glycogen stores in your muscles and liver.
Then as your body transitions to burning fat/ketones your brain will start to use ketones for energy as well – yes this means that your brain is getting Keto adapted.
The difference is that your brain does need some glucose (about 20% of it’s energy).
But you DON’T NEED TO EAT CARBS to get that glucose for your brain.
Your body has a wonderful mechanism for making glucose from either fat or protein.
The process is called gluconeogenesis which literally means making new sugar.
It is healthiest to synthesize glucose from fat because it’s cleaner and causes less strain on your liver and kidneys.
A fat molecule is made up of carbon hydrogen and oxygen, so when it is changed to sugar there are no by products like nitrogen and amino acids that can overload your kidneys.
If you need help getting into the Keto Mindset, check out this post.
Using Protein for Fuel is not good for you.
This might sound a little confusing because I just said that you are either a sugar burner or fat burner but don’t worry I am going to explain.
If you eat more protein than your body needs to build and maintain muscle, your body will turn excess/leftover protein into glucose by gluconeogenesis.
Then that new glucose is released into the blood stream, it causes an insulin response and if it is not burned, it is changed into fat.
In the process of protein-to-sugar gluconeogenesis, your body only keeps the carbon hydrogen and oxygen from the protein molecule and turns it into glucose.
The rest of the protein molecule which includes some amino acids and lots of nitrogen is filtered by your kidneys and excreted in urine.
Too much extra amino acids and especially nitrogen are hard on your kidneys and can eventually damage them.
Eating too much protein can also cause weight gain.
Super High Intensity Exercise on Keto
This is the full disclosure part of the post, there is one kind of exercise where performance can be improved by eating some carbs.
During high intensity exercise, you can burn both fat and carbs at the same time.
Most of us do not do this kind of exercise on a regular basis.
What I am talking about here are repeated short bursts like a professional football player or extreme endurance like a marathon runner.
My brother races mountain bikes, and before a big training day – 50 or 60 miles – he will eat some carbs.
Before the race he does a couple days of carb loading so that at race time all fuel sources will be available and he can have his best possible performance.
By contrast, I do a lot of 15-20 mile bike rides for fun, and I don’t need to load up on carbs to have a good time.
Exercise on Keto to build Muscles
I have said it before and I say it again, you lose weight in the kitchen and you build muscle in the gym .
Before I go further I would like make sure that I am being clear….weightlifting and muscle building are VERY beneficial for women too.
In fact probably more beneficial for women to lift heavy weights, not only to get strong lean muscle mass, but also to maintain bone density.
So how do we build muscle?
And what about just keeping the muscle that we have?
These are great questions, and they both have basically the same answer.
Strenuous exercise builds muscle by causing microscopic damage to your muscle tissue.
If you are a weightlifter, you know that when you’re building muscle you push your workout to muscle failure – i.e.. you just can’t do anymore.
What this does is create micro fractures in the ends of the muscle fibers, and then they need to be repaired.
The repair process uses protein to rebuild those fibers and in the process makes them bigger, better and stronger.
Maintaining your muscle mass is the same thing. Just less intense.
Protein is essential to this process, so you have to eat enough protein to support your muscle maintenance and repair.
How Much Protein Do you Need?
If you are trying to build muscle or you’re doing a lot of strenuous exercise, your daily requirement is going to be 0.7-0.9 grams of protein per pound of body mass. (150 pound person will need about 109 to 122 grams per day)
A person who sits on the couch will only need 0.3-0.4 grams per pound of body mass per day. (54 grams per day for a 150 pound person)
Endurance stuff like running or even lots of walking need 0.5 to 0.6 grams per pound per day. (150 pound person 82 – 95 grams per day)
Do you have to exercise to lose weight?
The short answer is no.
But it does help.
This morning I took my dogs for a little shorty walk. I walked 1042 steps and that burned a grand total of 21 calories more than if I had spent that time sitting in my recliner sipping coffee.
Now, if there are 3500 calories in a pound of fat, that means I would have to walk almost 174,000 steps to burn one pound.
By my calculations, that’s about 82 miles. I like to walk, but c’mon. Eighty two miles? Most of us don’t have time to do that.
I am sure that you have seen the posts, “Best Exercise for Weight Loss,” “Yoga for Weight Loss,” “Walking Your Way Thin.” they are in Men’s Journal, SELF and everywhere else.
There was even a hit TV show – “The Biggest Loser” where they torture overweight people with exercise and food temptation.
I hate that show for a lot of reasons, but I don’t have time for that here.
The fact is that exercise is great for your body for a lot of reasons but it doesn’t burn as much energy as you might think:
Walking – A 180 pound person burns about 100 calories per mile. A 120 pound person burns about 60.
Running – A 180 pound person burns about 150 calories per mile. A 120 pound person burns about 80.
Weightlifting – Your average 30 minute workout burns are 90 calories.
Yoga – Actually burns the same as weightlifting.
No Exercise – You do the math, and then head out for that 82 mile walk.
Thinking About Exercise – Your brain actually uses more energy than any muscle – or any other organ in your body for that matter.
Twenty to twenty-five percent of the energy your body burns is used by your brain.
So, sitting on my ass writing this post burned more calories than last night’s 2 mile walk.
I am sure you can see why eating right is so important to losing weight.
The Million Dollar question; Should you Exercise on Keto?
The short answer is not only yeah, but HELL YEAH!
Exercise is good for you and that is a fact.
It can contribute to your ability to lose weight by building a healthy heart, lungs and increasing muscle mass.
In fact, if you want to lose weight fast, check out this post on how to lose ten pounds in 7 days.
If you have more lean muscle, your base metabolic rate (BMR) increases, and that means you’ll burn more calories and lose more weight while lying on your couch, or sitting at a computer.
And that means that you will burn more calories and have more energy all the time.
Exercise is also great for your brain and your emotional health.
It reduces stress, and the stress hormone cortisol. Cortisol is also a fat storage hormone that can cause weight loss stalls.
Exercise contributes to high quality sleep.
When you move and stretch, you activate your lymphatic system that moves toxin out of you body.
Exercise is healthy, once you start it can even be a healthy addiction. Exercise make you feel good.
So for directly burning fat – exercise doesn’t really do that much but indirectly it definitely helps you trim down.
- You should recalculate your macros with every ten pounds that you lose.
- If you need a little help with how to eat out on the Keto Diet you should read this post.
- And this popular post on ” How to Cheat on Keto and Get Away with it” is great for the upcoming holiday season!
- Nine Signs of Ketosis to make sure everything is going according to plan.
In fact, if you are new to Keto or just getting a handle on how it all works the library of Keto Lifestyle posts contains a wealth of information about Keto and how you can make it work for you!