Following several requests from my readers, I will be sharing my thoughts on exercise and nutrition that is specific to those of who stay physically active and follow a keto diet. In this post, I'll try to cover the basic facts and myths about training on a ketogenic diet.
This post will not cover details of exercise nutrition (e.g. whether to eat carbs before or after exercise which is not as straightforward as you may think), essential supplements, specific types of training or my personal exercise routine. These topics are covered in this post: Keto Diet Nutrition & Exercise: Carbs - and many more will follow in my future posts. So let's start with some basics of training on a keto diet.
The "Exercise More and Eat Less" Dogma
When you ask people what is the purpose of exercise, the most common answers are:
- to lose weight (body fat)
- to get fit and stay healthy
- to look and feel good
- to build muscles and strength
When your goal is fat loss, the most common mistake is to go on a calorie restricted diet and add more exercise, usually prolonged cardio, in an effort to lose weight. When this approach fails, most people simply decrease their calorie intake and take on even more exercise. By doing so, most become physically and mentally exhausted with no real weight loss. The more they stick to this approach, the more likely they will overexercise and/ or overeat, putting an increasing amount of stress on their body. The side effects of that are accelerating the ageing process of their cells and increasing the level of chronic inflammation. This approach is simply not sustainable and can harm your body.
Years before I started following a low-carb approach, I used to spend hours exercising every week. In fact, I used to go to gym almost every day for an hour or more, usually doing cardio. I loved the euphoric post-workout feeling and I was sure that if I stayed focused, I would reach my goals. I was already quite lean but I couldn't lose the last 5 pounds. Considering how much I used to exercise, I couldn't understand why the scales weren't moving. With my seemingly "healthy" approach (high-carb and low-fat), I was exhausted and felt hungry most of the time. I was frustrated. Back then I didn't have any thyroid issues but I'm absolutely sure that apart from other factors, my high-carb low-fat dieting, low-calorie intake and overexercising played a role in developing Hashimoto's (an autoimmune thyroid disease) a few years later.
I bet many of you have a similar experience...
So, Do Calories Count or Not?
When you eat nutritious whole foods low in carbs, moderate in protein and high in fat, you'll naturally eat less. I know this is why low-carb diets often get misunderstood and people become confused. Calories do count - although not quite the same way - even on a low-carb diet. There may be a few lucky people who can eat twice as many calories as their maintenance level but just like most of you, I'm definitely not one of them.
The main reason why most people lose weight on a keto diet is simple: you will naturally eat less because low-carb diets have appetite-suppressing effects. Although this study suggests that low-carb diets have a metabolic advantage, the appetite-suppressing effect is by far the most significant factor. Also, it's not accurate to say that high levels of ketones will guarantee fat loss. I haven't seen a study that would prove such a claim. In fact, you don't even need to be in ketosis to lose body fat. High levels of ketones are desirable for therapeutic purposes rather than fat loss.
To help you find your ideal macronutrient intake, we developed a free online keto calculator, KetoDiet Buddy. Although most of you won't need to count calories on a keto diet, it may help you get a better idea of your macronutrients, especially protein intake.
Benefits of Exercise
One of the most common questions is whether you need to exercise to lose weight. There is no definite answer and here is why: Strictly speaking, you don't need to do any exercise to lose weight on a keto diet, however, there are several reasons why you should do moderate exercise.
- Improved bone mineral density. This study and several other studies show that resistance training improves bone mineral density in obese postmenopausal women.
- Improved immunity. This article explains some of the reasons why exercise may help you boost your immune system. Keep in mind that overexercising will have the opposite effect.
- Improving diabetes by increasing insulin sensitivity. This review of studies shows that high-intensity intermittent exercise (HIIT) increases insulin sensitivity by up to 58%, especially in patients with type 2 diabetes. The same source shows that moderate aerobic exercise lowers blood sugar levels while HIIT temporarily increases blood sugar: "The authors suggest that the addition of one 10-second sprint after moderate intensity aerobic exercise can reduce hypoglycemia risk in physically active individuals who possess type 1 diabetes."
- Brain health. This review article explains that exercise improves age-related cognitive decline and help prevent neurodegenerative diseases.
- Cardiovascular health. This review article explains how both vigorous and moderate physical activity help prevent coronary heart disease.
- Anti-ageing benefits. This review article explains how exercise may increase life expectancy by decreasing mortality risk factors like high blood pressure, type 2 diabetes, coronary heart disease, stroke and cancer (by at least 30%).
Acceleration of fat loss with moderate exercise?
As we age, our basal metabolic rate decreases and we (especially women) find it harder to maintain a healthy weight. With the right type of exercise, you'll increase your muscle mass and with more muscles, you'll even burn more calories at rest.
But here's the catch: The increased calorie burn is not as much as you may have thought. It's a common myth that just one extra pound of lean mass/ muscles will help you burn 30-50 calories per day at rest. If that were true, it would mean that with extra 10 pounds of muscle mass, I would be able to burn 300-500 calories and maybe even "enjoy" an extra bowl of breakfast cereals topped with honey. In fact, an extra pound of muscles will burn just about 6-10 calories. Ironically, even body fat cells require some energy to maintain themselves. When we lose body fat, our basal metabolic rate decreases so the net effect is even smaller.
As several studies and review articles show you cannot outrun a bad diet. Exercise by itself has an insignificant effect on weight loss in the long term. In this study, the authors concluded that exercise is not the key to the obesity epidemic. Although exercise is crucial for improving overall health and fitness levels, it will not help you lose more weight. The main reason seems to be that the more you exercise, the more you'll eat.
Change your mindset: Don't exercise just to burn calories and lose body fat. This approach doesn't work in the long term. Instead, exercise to build muscles and feel good about yourself. Whatever physical activity you chose, do it for pleasure. Focus on your diet, it's the most important factor for successful weight loss. If you are new to the keto diet, make sure you check out this free keto diet guide and sample diet plans.
What's Wrong with Cardio for Fat Loss
Moderate amounts of low-intensity cardio such as walking, hiking, swimming or cycling are health-improving activities. What is not beneficial is endless hours of extreme spinning, running or hard-core cardio classes. Honestly, how many of you ever got to the point where you couldn't lose weight no matter how much you tried?
As I outlined above, exercise has great health benefits. The problem is that most people think about cardio as a fat-burning tool. I used to be one of them. We have been told that this is the best way to burn extra calories, balance calories in vs calories out and exercise as often and for as long as we can... again to burn more calories.
Let me tell you something: This is a race you cannot win. I love running and I even attended a marathon event a few years ago. However, based on what I know now, I never use cardio for fat loss because it simply doesn't work. Using prolonged cardio for fat loss and burning calories is simply not a sustainable lifestyle for the vast majority of people. Below are the reasons you should cut back on cardio:
1. Chronic cardio (repetitious aerobic training) will make you more hungry and you will likely eat more... unless you force yourself not to eat. Increased appetite means that your body feels ravenous after prolonged cardio and will demand those calories back! Also, chronic cardio leads to negative changes in anxiety and mood.
2. Chronic cardio raises the stress hormone cortisol which is responsible for storing fat in the stomach area (visceral fat). Long-term elevation of cortisol levels also lead to leptin resistance. Leptin plays a role in appetite and body weight regulation and leptin resistance leads to increased appetite and food intake. Again, prolonged cardio will make you hungry.
3. Systemic/ chronic inflammation. Effective exercise is accompanied by acute inflammation which is necessary for building muscles and improving performance. However, exhaustive exercise will lead to systemic inflammation which you want to avoid. Also, this review article explains how prolonged exercise also leads to oxidative stress.
Studies show that low to moderate intensity, prolonged cardio exercise has an insignificant effect on long-term weight loss. Prolonged cardio is also linked to several negative health effects such as leptin resistance, chronic inflammation and oxidative stress. Just like Jeff Volek and Stephen Phinney say: Exercise is a wellness tool - not a weight loss tool!
Choose Wisely: Resistance Training and HIIT
Weight training (aka strength/ resistance training) and high-intensity intermittent training are the most effective tools for long-term fat loss.
When you do weight training, focus on major muscle groups and don't forget about squats! The muscle-sparing effect of ketogenic diets will help you preserve and build lean mass.
Will I get bulky? Putting on muscle is not as easy as many people think, especially if you are a woman. One of the biggest misconceptions is that women grow big muscles when they lift heavy weights. It's a myth: women don't have the same hormone profile to bulk up just like men do. You will get more defined but not necessarily masculine. Also, the type of resistance training and nutrition play a crucial role. And after all, it depends what you perceive as "bulky."
Weight training will help you build and maintain muscles and burn slightly more calories at rest. It's a myth that women will grow big muscles if they lift weights. It takes years of training and specially designed nutrition to get to that level.
High-intensity intermittent training/ exercise (HIIT/ HIIE)
What is interval training? It's a training technique in which you alternate intense bursts of anaerobic exercise such as sprinting with short recovery periods. One of the effects is that you burn more calories in less time compared to other workout routines like prolonged cardio.
I already mentioned that you should not exercise just to burn extra calories but this is quite different in the case of HIIT. This study shows that an HIIT session made the participants less hungry than a low-intensity cardio session which significantly increased their appetite. Additionally, this review of studies explains how HIIT outperformed cardio exercise in terms of fat loss in both short-term and longer term studies. The authors suggest that: "Possible mechanisms underlying the HIIE-induced fat loss effect include increased exercise and postexercise fat oxidation and decreased postexercise appetite." If you want to know how a typical HIIT session looks, check out these videos from Bodyrock on Youtube - there are different HIIT sessions for both beginners and advanced levels.
Not Yet Fat Adapted? Take it Easy!
If you just started following a low-carb diet, go easy on exercise. You will likely feel too tired to exercise the way you used to. Don't worry, this is only temporary! Feeling tired for the first couple of weeks is natural as it's one of the side effects of carbohydrate withdrawal.
When you significantly reduce your carb intake, your body needs time to get fat adapted, i.e. learn utilising fat and ketones for fuel instead of glycogen. Light cardio such as hiking and long walks are a good way to start if you wish to include exercise early on.
Exercise regularly but don't overdo it. Make sure to include rest days and get enough sleep. In general, exercise is good for you but be careful not to overdo it. Overexercising
increases the risk of injury, negatively affects the immune system and increases stress-related hormones. Mark Sisson listed eight signs of overtraining in this post.
I consider myself moderately active. I won't go into great details of my workouts in this post but here's what I do: I walk daily for 30-45 minutes and exercise 3 times a week doing either weight training or HIIT. For weight training, I spend 30-45 minutes per session, including stretching and warmup times. For HIIT I spend no longer than 15-20 minutes per session.
Lastly, set yourself a realistic goal. You should be aiming to lose no more than 1-2 pounds a week. If you need to use a keto calculator, don't go for large calorie deficits: Ideally no more than 500 kcal deficit and depending on your BMR and activity level, shoot for a reasonable energy intake of 1400-1800 kcal. Remember, low-carb diets are sating and you will naturally eat less. Reaching a weight loss plateau may be caused by several reasons and you don't necessarily have to be eating too much, in fact, you may discover that you haven't been eating enough.
You can read even more about protein, carbs and exercise nutrition in these posts: Ketogenic Nutrition and Exercise: Protein and Ketogenic Nutrition and Exercise: Carbs
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