Why exercise on Keto?
Keto is a tried-and-true weight loss plan that causes the body to burn through its stored fat. The simple act of carb-cutting and eating keto foods (and sticking to it) is going to yield results, if only for the simple reason that carb-heavy, sugary foods tend to contain large amounts of calories.
Part of the wonder of keto is that you get to eat satisfying, tasty meals that make you shed kilograms. Thanks to ketosis, this can happen even without exercise!
There are, however, a few reasons why we highly recommend exercise with your keto. Its positive effect on wellness -- both physical and mental -- is the primary reason.
It's hard to argue with study after study demonstrating exercise's rewards. But there are more reasons. With regards to keto, it's been shown that exercise can hasten the onset of ketosis and get the metabolism back on track faster if ketosis is lost. It burns calories, which speeds up weight loss. If you're doing keto and find you've reached a weight loss plateau and feel stuck, increasing exercise will jumpstart your progress.
Just like meals, drinks, and desserts, there are types of exercise that are more keto-friendly than others. It's important to be in tune with your body as you make new adjustments to keto, and finding your favorite and most effective way to exercise is all part of the journey. As you progress, do what makes you feel the best.
High intensity/low intensity exercise
On a low carb diet, it's usually better to go with low intensity exercise, at least at first. In the world of fitness and weight loss, workouts are said to be "high intensity" if they are performed in short bursts with a high level of energy expended very quickly and "low intensity" if the energy expended is lower and performed over a longer duration.
Some examples of high intensity exercise are: Stair climbing, jumping rope, sprinting, CrossFit, and interval training. High intensity workouts maximize heart rate and burn lots of calories in a short period of time. They quickly build endurance and improve cardiovascular function, which can be helpful for people who don't have the time for protracted workouts, are training for an athletic competition, or are looking for fast-and-hard progress.
Low intensity workouts include: Jogging, rowing, steady walking or cycling, lap swimming, distance running, and yoga. These can be endurance workouts that last from 30 minutes to over an hour. Energy is released and burned continuously and steadily -- not in short, powerful bursts.
Low intensity exercise provides the same benefits as high intensity exercise, but not quite as fast. The reason it's recommended over its harder counterpart is because it works much better with keto's two major energy providing processes: ketosis and glycolysis.
Ketosis, glycolysis, and working out
It's especially important to avoid high intensity workouts in the beginning when your body hasn't yet "learned" the ability to convert fat into readily available energy. In the carb-adapted body, the energy required to work out is provided by consuming lots of carbs prior to exercise. Carbs are quickly converted to glucose and that glucose is converted to ATP (adenosine triphosphate) and used as energy for the contraction of muscles.
In the absence of consumed carbs, glycolysis converts stored glycogen (found in the liver and muscles) to energy. During low intensity workouts, the process is called aerobic glycolysis, which simply means the body is using oxygen to access its own energy stores. If the exercise is slower and steadier, even if your heart rate is high and you're working hard, a sustained supply of oxygen is entering the body.
At high intensities, anaerobic glycolysis kicks in. Muscles are contracting and working harder than oxygen can keep up with, so glycolysis happens anaerobically -- without oxygen. This can lead to a buildup of lactic acid, which causes muscle cramping. Without regular replenishment of carbs, it's really difficult to keep doing high intensity activities. Performance suffers, and injuries become more likely.
After prolonged ketosis, where ketones supply the body and brain with fuel, the body becomes fat adapted. Glycogen exists in muscle cells and the liver for use in the short term. That's why, before fat adaptation, you might run out of energy quickly during exercise once glycogen stores run low. When fat adapted, the metabolism makes a smooth transition from burning glycogen to burning triglycerides -- the energy-providing molecules found in fat cells (adipose tissue). It's even possible to do regular high intensity workouts when fully fat adapted.
Burn fat, not carbs
Here are a few reasons to unlock the fat-burning potential of exercise on keto:
- Stored body fat is actually a better and more efficient fuel source than carbs.
- When the body is free from the carb-intake cycle, there are no more spikes in blood sugar.
- Burning fat during exercise leads to weight loss, of course.
Again, it will take time and dedication to keto to get to the point where your body prefers burning fat over carbs. When it happens, you'll probably see improvements in athletic performance.
High intensity workouts become more possible the further your body adjusts to keto. As with all things keto, some experimentation and consulting with a professional can lead you to your ideal personalized workout scheme.