The ketogenic diet and exercise do not have to be done separately. I can’t tell you how many times I’ve seen cautions in ketogenic groups about exercise. There are plenty of ketogenic dieters that exercise. Exercise is great. Our bodies were meant to move. If you’ve jumped on the keto bandwagon because you are overweight, burning more calories will help to burn off more fat. You will see faster results.
It’s good for the heart, builds muscle to keep you lean and toned, and strengths the bones. Thankfully, exercise can completely fit into your routine while eating for ketosis. You just need to keep in mind a few simple considerations:
Types of Exercise
There are four main types of workouts that you can do. They are typically classified as aerobic, anaerobic flexibility and stability.
Aerobic exercise, is commonly referred to as cardio for its cardiovascular benefits, is anything that lasts over three minutes. These exercises are often lower intensity, steady exercises. They help with fat burning. It is very keto-dieter friendly.
Anaerobic exercise, is also known as HIIT, or high intensity interval training. This involves shorter bursts of energy. Weight lifting is another example of anaerobic exercise. Carbohydrates tend to be the primary source of fuel for anaerobic exercise. Therefore, fat can’t provide enough energy for this workout. Ketogenic dieters may want to save anaerobic exercise until their body has become fat adapted. There are weight lifters who do follow the ketogenic diet.
Flexibility workouts are helpful for stretching your muscles’, supporting joints and increasing your range of motion. These workouts often include yoga, stretching, and Pilates exercises. Flexibility workouts can be easily incorporated into a ketogenic dieters lifestyle without too much planning or effort.
Stability exercises are exercises that include balance and core training. Stability exercises will help to improve your muscle strength, your control of movement and your body’s alignment.
As you are getting into ketosis and once your body is in ketosis, selecting the correct workout will make a difference. During low-intensity aerobic exercise, the body will use up fat as its primary energy source. During high-intensity aerobic exercise, carbohydrates are the primary source of energy. However, when you enter ketosis, you’re constantly using fat as your primary energy source. Before your body becomes fat adapted, this can make high intensity exercise more difficult.
The great news is that the body will adapt to low carbohydrate eating and using fat for fuel. This process typically takes about two to three weeks. During this time, it is best to focus on aerobic exercises and not to stress the body out too much with high intensity workouts.
During keto-adaptation, the body isn’t getting carbohydrates for energy. It then must turn to the secondary source of fuel, which is fat. This will change how the body utilizes energy when workout out. Fat will become the preferred source of fuel for muscles’, since glycogen isn’t present without carbohydrate intake. The longer someone goes without carbohdyrates, the more the body adapts to using fat and ketones as a source for fuel.
During ketosis, the body can create its own glucose to use during anaerobic exercise. This happens through a process of converting protein into glucose. The process is known as gluconeogenesis. The body creates ketone bodies that it can use for fuel. The body will then efficiently start to use fat for fuel during exercise.
How The Ketogenic Diet Impacts Performance
Through carbohydrate restriction, we start to limit the ability of our muscles’ to access sugar, which is one of the fast fuel sources. Without enough sugar, the muscles’ ability to function at high intensities (any activities extending beyond 10 seconds) becomes impaired. After about 10 seconds of near maximal to all out effort, the muscles’ will begin to rely on glucose for energy through a pathway called glycolysis instead of the phosaphen system. The phosaphen system depends on creatine phosphate and ATP, not glucose. Any muscular activity that requires near maximal to all out effort for 10 seconds to 120 seconds is only able to be fueled with glucose.
Ketones and fat can not stand in for glucose in the glycolytic pathway. It will take about 2 minutes of exercise for your body to start to shift metabolic pathways that can burn the ketones and fat. Restricting carbohydrates means that the body does not have the sugar that it needs to fuel activities that require a high intensity effort for 10 seconds to 2 minutes. For these activities, the ketogenic diet can limit your performance. This would include lifting weights that are heavy enough to take you to failure, sprinting, sports such as soccer and rugby, etc.
You may notice that your performance levels for these sports may dip when you start the ketogenic diet. This is completely normal and expected.
Doing Cardio on Keto
Due to the nature of cardio exercises, the ketogenic diet will not impair your performance. The wonderful part of cardio is that you don’t have to exercise at high intensities that require you to burn sugar and glycogen to get results. You simply need to get your heart rate up and keep it up.
For cardio exercise, you should select the right intensity to get the most benefits. The CDC defines this as moderate intensity, or getting your target heart rate up to 50-70% of your maximum heart rate.
There is an equation to figure out your maximum heart rate. Subtract your age from 220. For example, if you are 50 years old, the estimated maximum age related heart rate would be calculated as such: 220-50=170 beats per minute. To calculate the range, you would multiply 170 X .50 = 85bpm and 170x .70 = 119 bpm. Therefore, the target range that you want for your heart rate will be 85-119 beats per minute (bpm).
During your adaptation phase of the ketogenic diet, you should aim for the lower end of the range, or the fifty percent level. After you have been on the ketogenic diet for a few weeks, you will be able to maintain a higher heart rate longer without needing to burn too many carbohydrates.
As you are adapting to the ketogenic diet, aim for the lower end of the range (50% level). After a couple of weeks on the diet, you will be able to maintain a higher heart rate for longer without needing to burn too many carbs. If you are new to exercising, you will want to build up your endurance. Start with 50% of your max heart rate for 10-15 minutes. Then you should increase the duration of exercise by about five minutes each week until you can comfortably complete 30-45 minutes with your average heart rate around 50% of your calculated max.
When you can comfortably complete 45 minutes with your intensity at 50% of your max heart rate, it will be time to start increasing your intensity. You will gradually work your way up to around 70% of your max heart rate.
Some great cardio exercises that you can do:
- circuit training
- aerobic workouts
- recreational sports
Carbohydrate restriction may or may not decrease your strength and power in some of these activities as you adjust to the ketogenic diet. If your goal is to get a great cardiovascular workout, there is no need to push yourself to your maximum when doing cardio. The length of time that you do cardio will matter more.
You definitely can increase your strength, power and cardiovascular health while following a ketogenic diet. However, it takes a bit more mindful exercise planning and some heavy weights.
In the beginning of the ketogenic diet, you may notice a drop in your athletic performance. However, as your body adapts to the ketogenic diet, you’ll start to notice that you feel healthier overall. Your body’s inflammation levels will decrease and your health will increase. As it does this, you will be able to resume your higher intensity workouts and improve your performance without much worry or concern.
By combining the ketogenic diet with the cardiovascular workouts, you will notice an increase in weight loss if you have weight to lose. The cardio exercises tend to rely on fat for their fuel and combining them with a diet that encourages the body to burn fat as its primary fuel will lead you to faster results.[