If you train in karate or in any other martial arts, you probably have often seen martial art instructors with big bellies and are puzzled about this phenomenon like I do. They train regularly and they train hard so why do they still manage to develop those big guts and unhealthy bodies?
They are definitely not lazy, weak and unfit, lacking discipline nor haven’t pushed themselves hard enough.
It turns out that training for long hours every day all year round can be counterproductive. While karate training can be a high-intensity physical activity, it does not burn as many calories as people may think. Over-training can also lead to increased inflammation and other health risks. This couples with an unhealthy diet and it’s easy to end up with a big gut and likely poor health.
In this post, we will look at those contributing factors in more detail and what you can potentially do to fix it if you are amongst those with a “karate belly”.
Increased training time does not result in a linear increase in calories burned
Karate instructors spend many hours instructing as well as training on their own on a daily basis. However, unfortunately, the number of calories burned does not proportionally correlate with training duration and, even though they may train a lot, they don’t burn a lot of calories.
The present American College of Sports Medicine recommendations for moderate-intensity physical activity to maintain health and promote weight loss are as follows: 
- Maintaining and improving health: 150 minutes per week
- Prevention of weight gain: 150-250 minutes per week
- Promote clinically significant weight loss: 225-420 minutes per week
- Prevention of weight gain after weight loss: 200-300 minutes per week.
Martial art instructors would spend between 2 to 4 hours a day at least between instructing and personal training. A Japanese karate instructor in his 70s once told me that he’d train on average about seven hours a day. So, it’s pretty certain that most instructors’ training time would well exceed the recommended levels of physical activity for weight maintenance and weight loss.
Given how much time they spend training and the massive amount of calories burned per hour, we would expect to see all karate instructors to be in great shape. But we don’t. Karate instructors with large bellies are commonly seen and it’s definitely not because they don’t do enough exercises.
One main reason for this phenomenon is probably the human body’s great ability to adapt to increased physical activity by conserving energy and down-regulating other aspects of physiology. 
If you have never trained in karate before and you turn up at a dojo for the first time, you will have a great workout and you will come home physically and mentally exhausted and you will burn a lot of calories that day for sure.
This is because your brain is very busy making new neural connections and establishing new pathways for activities that you have never performed before. And, in case you haven’t already known, your brain consumes a lot of energy to perform those tasks. Weighing at approximately just 2% of total body weight, our brains consume a whopping 20% of total energy expenditure!
However, you will feel a little better after the second training session and a little better after the third one, and so on. And, after a few months, you will likely blitz through each training session without much trouble.
This is both good and bad for you. It’s good because you’ve become familiar with a lot of techniques and they are no longer hard for you to follow along and you also become a lot fitter. But it’s bad for you if you want to lose weight because you won’t burn as many calories as you do at the beginning.
Your brain doesn’t have to work as hard as it does initially anymore (referred to as “neural efficiency”) because some levels of automated responses have been established. Accordingly, the total energy burned per training session will be reduced and you will eventually reach a plateau at some stage. [5, 6, 7]
This applies to other forms of physical activity like running, swimming, or playing sports as well. If you don’t have any running experience and decide to train to participate in a marathon, you’ll surely burn calories like crazy initially. But after a few weeks, your body will adapt and won’t need to spend as much energy doing exactly the same task anymore. For example, marathon runners have been found to burn 6200 calories a day at the start of a race, but only 4900 calories at the end of the race, despite covering the same distance. [8, 9]
Being more physically active in the long run does not mean you will burn more calories. The Hadza, a traditional hunter-gatherer society living in Tanzania, is amongst the very few communities that still live a truly traditional way of life. They have to hunt and gather wild food each day to live using bows, arrows, axes, and digging sticks and they have to do it on foot. They are about 5 to 10 times more physically active than typical Westerners. Naturally, you would expect the Hadza to burn a lot of calories daily and burn a lot more calories than typical Westerners, but they don’t. 
When a group of researchers went to measure their daily expenditure, they were shocked to find that the average daily energy expenditure of the Hadza hunter-gatherers was no different than the sedentary Westerners after controlling for body size. The researchers didn’t believe what they found and so they went back and measured again using a different metric, but they got the same answer. The researchers hypothesize that our daily calorie expenditure may be an evolved physiological trait rather than a product of our lifestyles. [11, 12]
In summary, karate instructors train regularly, hard, and for long periods of time but it’s likely that they won’t burn a lot of calories. This is consistent with available research evidence in this area.
Too much training can stress the body
In addition to the adaptive response to repeated physical activities discussed above, too much training can actually stress your body and cause havoc on your health.
Leisure time physical activity (e.g. hobbies, sports, dances, and transportation that are undertaken during non-work time) has been found to improve health and increase life expectancy. However, occupational physical activity (performed during working hours) has been found to be detrimental to one’s health. [13, 14, 15, 16, 17]
That is, if you play sports, take dance lessons, or ride to work, your health is likely to improve. But if you are a cleaner, a construction worker, a farmer, or an aged care staff who is physically active for most of your working days and for most of the time, you are likely to be in poor health.
This phenomenon has been referred to as the “physical activity paradox”.
It turns out that, like many other things in life, too much of a good thing is bad for you. Being overly active and training for long hours every day and all year round can be bad for your health too.
Several hypotheses have been proposed to explain the “physical activity paradox”. One hypothesis that is particularly relevant to the current discussion is that occupational physical activity is often performed with insufficient recovery time which results in increases in levels of inflammation. 
Karate instructors are likely to train daily and for long hours and they don’t have sufficient time in between training sessions to let their body recover. Over-training can lead to fatigue and exhaustion, causes inflammation, and increase the risk of cardiovascular disease. [19, 20]
Prolonged and excessive aerobic exercise efforts such as marathons, ultra-marathons, full-distance triathlons, and very-long-distance bicycle rides are inconsistent with our genetic heritage.
The pattern of exercise for which we are genetically adapted involves a diversity of activities performed intermittently, at moderate intensities and moderate durations.
Even in highly trained individuals, high-intensity, multi-hour endurance exercise effort is associated with damage to the myocardial cells and connective tissue.O’Keefe et al (2010) “Achieving Hunter-gatherer Fitness in the 21st Century: Back to the Future”, American Journal of Medicine
Ongoing chronic stress raises cortisol levels and elevated cortisol has been linked to weight gain, further contributing to the “karate belly” phenomenon.
People who devote their lives to studying a specific area that they love are often oblivious to what’s going on in other fields. I think many karate instructors suffer from this narrow focus too.
They devote all their time to training, instructing, and studying karate thinking that, with that much physical activity, they’ve done more than enough to take care of their own health, and they pay no attention to their diet.
They generally consume whatever tastes good and is convenient to get near their dojos: burgers, pizzas, Chinese takeaway, frozen meals, snack bars, chips, and the like.
These types of foods are typically calorie-dense and nutrient-void. This combines with improved appetite after a long training session (that often doesn’t burn as many calories as they think) which leads to increased calorie intake and you can see why they end up with those large bellies.
Some instructors who carry large amounts of belly fat with them can still exhibit awesome power but having too much abdominal fat (also called visceral fat) is really unhealthy.
Abdominal fat wraps around vital organs and having too much abdominal fat is a sign of metabolic syndromes such as obesity, insulin resistance, diabetes, and high blood pressure. Excess abdominal fat has been linked to a number of health problems including heart disease, diabetes, liver diseases, fertility issues, cancer, and a higher risk of death. [21, 22, 23]
What can you do?
The first thing you should do is improve your diet. You really can’t out-train a bad diet. Try to eat whole food and nutrient-dense food. Eat good quality proteins (like beef, lamb, pork, chicken, and fish and good fats (from fatty meat cuts, lard, ghee, and butter), and a very small quantity of good quality carbs (e.g. low-sugar fruits and low-carb vegetables). In other words, follow a low-carb or ketogenic diet which has been shown to be very effective for weight loss as well as offer other health benefits. [24, 25]
You should avoid all processed food and seed oils (e.g. canola oil, corn oil, soybean oil, and blend vegetable oils) which are high in pro-inflammatory polyunsaturated fats. Polyunsaturated fats (omega-6 in particular) have been linked to many chronic health problems, including obesity, liver disease, cardiovascular disease, inflammatory bowel disease, Alzheimer’s disease, and arthritis. 
You might be familiar with the dietary guidelines that recommend avoiding saturated fats and replacing them with carbohydrates and polyunsaturated fats and have been following this advice. However, emerging evidence shows that the increase in carbohydrate consumption was “the causative dietary factor for the diabetes and obesity epidemic in the US” while replacing saturated fats with omega-6 polyunsaturated fats actually leads to an increased risk of heart disease and overall mortality. 
In addition to changing your diet, you can vary your training and intensity levels to continue challenging your body and at the same time give it sufficient time to recover and reduce stress and inflammation.
Switching up your training programs will challenge you mentally and boost energy expenditure, for example, trying out Aikido, Judo, BJJ, Kendo, weight lifting, or yoga. Training in other martial arts or engaging in activities other than karate reduces your time for karate training but makes you a well-rounded and better fighter.
In addition, by varying intensity levels or focusing on different techniques each day (hand-technique days vs leg-technique days, for example), you will avoid overtaxing your body day in and day out.
You also don’t need to train with 100% intensity every time to get the most out of your training. For example, go for 60-70% intensity most of the time but occasionally push yourself to the maximum limit. Also, visualizing can be a very effective supplementary form of training because your brain can’t differentiate between pure imagination and actual physical actions. You can give your body the time it needs to rest and recover without compromising your progress in karate.
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