If you’re like most athletes, you probably assume that the ideal body fat percentage is lower rather than higher. Well, you might be right, and you might be wrong. Body composition isn’t as straightforward as you might think. In this article we’re going to look at several scientific articles that examined ideal body compositions for different types of athletes including: Crossfit athletes, NFL Players, Navy SEALs , and more. Keep reading to see what your ideal body composition might be.
Before we move into the meat of this article, I want to point out that I’m not getting into body shaming, or fit at any size arguments. Honestly, I don’t really care. Your self-worth isn’t reflective of your appearance, but carrying too much or too little weight can certainly be unhealthy. I plan on keeping the conversation on the analytical side. The first question we need to ask ourselves is what is the ideal body fat percentage?
What is the Ideal Body Fat Percentage?
As a functional fitness coach of many years, and very experienced internet weirdo, I will naturally reply to your question with one of my own. What do you want to do? Ideal body body fat percentage changes depending on your athletic requirements. An ultra endurance runner should have less body fat than a super heavy weight power lifter!
Moreover, we often have unhealthy expectations of body composition goals due to social media, and heavily edited photos of bodybuilders and physique athletes. If you’ve read my previous article on how common steroids, and PEDs are in recreational athletes, you’ll understand that it’s not just the pros that are on the sauce.
Seeing the physiques and performances of enhanced athletes can give us unrealistic expectations on what is the norm. This is super common when talking about body fat percentages. After all, everyone should have a six pack and a 500 pound squat right? Wrong! Certainly, some athletes can do this naturally, but they are definitely in the minority. Now let’s talk about the purpose of body fat. News flash, it does more than just store energy.
The Purpose of Body Fat
Body fat has three primary purposes. It stores energy that can be burned in times or caloric deficit through a process called lipolysis. It also regulates various hormones in your body, and it helps maintain your body temperature as well. If you want to truly nerd out on the scientific details on body fat, then you should check out this article on the topic. While we won’t go into that level of detail, let’s talk about each of these functions in a little more detail.
Body Fat as Energy Storage
In times of caloric surplus your body stores excess energy in body fat, which is also know as adipose tissue. Each pound of adipose tissue holds 3,500 calories. This means that a 200 pound man with 15% body fat has approximately 105,000 calories of storied energy in his fat tissues.
Theoretically, this amount of stored energy would allow this same man to run for 7000 minutes. If he ran at a constant speed of 7 mph he would cover 816 miles! Obviously, this is theoretical, as no one can run at that speed for that distance. The point is that even relatively lean athletes carry an enormous amount of energy in their body fat!
These numbers are impressive, but they don’t tell the full story about body fat. It’s just as important in regulating your hormones.
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Body Fat and Hormonal Regulation
For many decades scientists and coaches only thought of body fat as an energy depot, and only considered the ideal body fat percentage in that light. Check out this snippet from a journal article on fat.
adipose tissue has been historically considered merely an energy storage depot, but this concept was revised following the discovery of leptin, the first adipocyte-derived cytokine, by Friedman’s group in 1990. Leptin release in response to changes in nutritional status indicates that the adipose tissue acts as an endocrine organ involved in modulating energy homeostasis (14, 15)
Adipose Tissue Remodeling: Its Role in Energy Metabolism and Metabolic Disorders
While we don’t need to know the dozens of hormones your body uses to regulate it’s body fat, it’s important to note that gaining or losing body fat is not as simple as modulating your caloric intake. If you have hormonal imbalances, then weight gain or loss might be nearly impossible. Now let’s move onto the last major function of adipose tissue, thermal regulation.
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Body Fat and Thermal Regulation
Body fat acts as an insulator. In fact, in very cold environments, your body actually remodels fat tissue into a specific type of brown adipose tissue that is rich in mitochondria. This brown fat tissue helps generate heat by burning its energy stores.
Thermal insulation does work both ways, and excess body fat can be a hinderance in very hot environments. In fact there is some research that shows the ideal temperature for marathon races is around 50 degrees Fahrenheit. Check this quote out.
Endurance performance is impaired in the heat, and a combination of high temperature and high humidity presents a major challenge to the elite marathon runner, who must sustain a high metabolic rate throughout the race. The optimum temperature for marathon performance is generally about 10–12°C. The optimum temperature may be lower for faster runners than for slower runners. Sweat evaporation limits the rise in core temperature, but dehydration will impair cardiovascular function, leading to a fall in blood flow to muscle, skin and other tissues. There is growing evidence that the effects of high ambient temperature and dehydration on performance of exercise may be mediated by effects on the central nervous system. This seems to involve serotonergic and dopaminergic functions.
Distance running in hot environments: a thermal challenge to the elite runner
You can see that body fat does more than make your T shirts fit funny. It has three primary purposes and can drastically affect athletic performance, both by retaining excess body heat, and by simply adding more mass that has to be moved or lifted. The ideal body fat percentage must be optimal for your caloric storage needs, as well as hormonal and thermal regulation requirements. Next, we need to talk about good and bad ways to measure your body fat.
How to Measure Your Body Fat
There are quite a few ways to measure body fat. Some of them are very practical and can be done at home, where as other’s will require expensive lab equipment. As you might imagine, medical imaging devices and specific lab tests are the most accurate methods. However, some of the easier methods are surprisingly accurate as well. We’ll cover some of the more common methods, and talk about their pro’s and con’s.
DIY Body Fat Measurements
If you’ve ever downloaded my ultimate nutrition calculator for functional fitness, you’ll know that I advocate for measuring your body fat with a tape. This method is very accurate, and only requires a scale and tape measure. While your weight on a scale can fluctuate, your tap measurements are much less variable, which gives you a better idea of your progress.
The next commonly used method is bioelectrical impedance testing. You can purchase scales, or other devices where you touch metal pads, and a small micro current is sent through your body to measure your body fat. These devices are notoriously inaccurate.
If you measure your body fat prior to a workout, and then measure it after. I bet it reports you’ve dropped body fat, which you haven’t. These devices are measuring the resistance from water in your body. Fat has a certain amount of water in its cells, so the device thinks that less water equals less fat. If you want to use this device just measure yourself in the same way, at the same time, and it should be fairly precise if not accurate.
Lab Body Fat Measurements
The most accurate methods are laboratory measurements. You can do these measurements with MRI machines, as well as measuring the rate of decay of special isotopes that you drink. However, if you want to get a very accurate measurement of your body fat, you can often find businesses that use dual-energy X-ray absorbtiometry machines (DEXA).
DEXA scans are a weak form of X ray that can accurately measure body fat. In fact, researchers often use this method when they need to measure body fat for their research subjects. It’s accurate, and reasonably easy to find in most urban areas.
We’ve covered a lot of the background info on body fat, including what it actually does, and some methods to measure it. Now we will cover some research on ideal body fat percentages for different types of athletes. This will allow us to see what commonalities exist for similar athletic requirements.
Ideal Body Fat Percentage for Top Crossfit Performance
In my experience, there is a sweet spot for most athletes when we are talking about functional fitness performance. When you boil down all the fluff surrounding functional fitness, you begin to realize that the goal is to increase power to weight ratio across all time domains. If you weigh less and can lift more, you’ve increased your strength ratio. If you weigh less and can run faster, you’ve increased your power output relative to body weight.
The trick is that getting too lean will actually hamper your athletic performance in strength and endurance. Let’s take a look at a piece of research that measured body fat in athletes that competed in local CrossFit competitions, and also competed at the international level.
There are three categories here ADV or advanced Crossfitters who are internationally competitive, REC who are locally competitive, and CON or control which are normal chain gym goers. We can see, in the ADV group, that both men and women have around 11% body fat. REC women have 23% body fat on average, and REC men have around 16% body fat. The control group women are around 24%, and the men are around 14%.
I do want to point out one important issue with this study. When you examine the athlete’s testosterone levels, you’ll find that the recreationally competitive women actually have higher T levels than some of the men. This almost certainly indicates some doping, medical issues, or test inaccuracy. So we should interpret these results with a grain of salt.
However, the take away is that the most competitive CrossFit athletes have and ideal body fat percentage of 11%. Using my non calibrated eyeball, I’d say that this is right around what many CrossFit Games athletes are walking around at, during their competitive season. Let’s take a look at other types of athletes to see how they compare to functional fitness athletes.
Ideal Body Fat Percentage for Military Athletes
Most military athletes aren’t super lean. Sure, you can find some that are ripped, but most of them just look like people that workout regularly. This study examined differences between different ranks of Navy SEALs, and compared them on body composition, amongst other things.
They found that the most successful SEALs had around 16% body fat. In fact, of the 225 active duty SEALs examined in the study, the leanest SEALs had 10% body fat. This might be surprising to some folks, but you need to remember that SEALs are often in a caloric deficit on missions. Moreover, they are often deployed in cold environments. Both of these operational requirements demand some body fat reserves to allow them to function well.
Now let’s take a look at some other athletes with similar characteristics to military and CrossFit athletes.
Ideal Body Fat Percentage for Football and Rugby Athletes
Rugby, American Football, are sports that require some conditioning, and a lot of strength to be successful. The requirements vary depending on position, but they are broadly similar to functional fitness athletes.
American Football Players Ideal Body Fat Percentage
A few years ago the NFL allowed researchers to conduct a study on all the athletes entering the NFL combine. This study ran for a number of years, and measured the body composition of more than 1900 athletes. Check out this graph depicting the body fat of drafted vs undrafted players.
The average body fat for all players in the study was 14.7%. You can clearly see the trend here. Drafted players are always leaner, in every position. The leanest athletes are around 7-8% body fat, and the fluffiest players are in the low 20% range.
This is a great study, as it has a huge number of participants, and it truly measures elite athletes. Many studies look at small numbers of athletes, and can’t capture extreme outliers because of the few participants. There are so many people attempting to get into the NFL that only the very best even make it to the combine. This allows us to draw some meaningful conclusions.
It appears that there is no benefit for athletes to be under 7-8% body fat. In fact, the athletes with the best mix of conditioning and strength are right around the 10-12% range. Next, let’s look at a sport with a little more endurance requirement than American Football.
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Rugby Player Body Composition
This study looked at European Super League Rugby Players, and measured their body fat via DEXA scan. They found that the fastest running players, the backs, were right around 13 percent body fat. The larger stronger players were between 15-16% body fat.
If you’re not familiar with Rugby, it’s quite the sport. I happened to play it in college (rather poorly). In Rugby the largest players, the forwards, spend the most time jogging, and perform most of the tackling. The faster players, the backs, generally either sprint at high speed, or stand around. This means that everyone needs a fairly high amount of conditioning, in addition to strength.
I would say that Rugby players are very close in the amount of conditioning they posses compared to a functional fitness athlete. From this study, we can estimate that very well conditioned athletes, that are very strong by the way, do best around 13-15% body fat. We’ve reviewed a lot of research, so let’s see what this means for functional fitness athletes.
Discussion
I think the data on CrossFit athletes, SEALs, and professional team sport athletes indicate that there is certainly a sweet spot for body composition. For men, I would recommend an ideal body fat percentage between 10-12% body fat. For female functional fitness athletes, it’s more likely that they will function best between 12-15% body fat.
Functional fitness WODs are varied and require us to move our body weight often. Higher body weights are generally more likely to be a hinderance than a help. Sure, larger athletes do have an easier time with assault bike and rowing WODs, but those are only two modalities.
If you’re looking for peak performance, then these ranges are probably what you should shoot for. However, you need to understand that everyone is a little different. Some athletes are naturally lean and might perform best under this range. Similarly, other athletes naturally carry more body fat, and can be peak performers above this range.
Final Thoughts
I want to emphasize that all of these studies are correlational in nature. This means that they are looking at some performance and seeing it’s relationship to body fat. It does not mean that low body fat causes high performance. It means that leaner individuals (to a point) tend to perform better.
If you have very specific fitness requirements, or you require high levels of strength, then you will likely to need to carry more body fat to reach your absolute strength threshold. If you want to be a great functional fitness athletes, then you have some guidelines you can shoot for.
If you have any questions, or want to argue with a stranger on the internet, feel free to put some comments below. I’ll get you an answer, or at least a rebuttal! Now get out there and get training!
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