Is a leaner athlete better? Finding the optimal racing weight
Published: 17.02.21
Weight loss to improve performance is a common goal of athletes looking to improve performance, especially in endurance sports. However, losing weight is not always the right choice. Lower weight doesn’t always mean better performance!

What does athlete’s body look like?

There is not one ideal body for an athlete. Athlete bodies differ across sports, genders, and genetics play a role as well.

The bodies of elite athletes are the result of good genetics, training, rest, and diet. A combination that is unattainable for most people.

At the same time, even athletes at their ideal competition weight can look different. One may be more chiseled, while another athlete may have more fat at their peak form.

athletes body types

Sprint to look like a sprinter

We can see different body types dominate in different sports.
Endurance athletes are notoriously thin.
Sprinters can be thin or muscular.
Swimmers have wide shoulders.
Probably the most notorious comparison is between marathoner’s and sprinter’s  body. It is a kind of deception, though.
If you start sprinting you will not look like an elite sprinter. If you start running longer distances, you will not look like an elite marathoner.
Elite athletes have exceptional genetics that predisposes them to certain sport combined with specific training that pushes their body to adapt to the extreme ends.
Most athletes do not perform nor look like these extreme examples. If you do, this is not an article for you 🙂
Having balanced training including strength training and cardio workouts supported with the right fueling will make you look, feel, and perform your best while staying healthy.
Raonic and Djokovic

What is the ideal body fat level?

We commonly admire “chiseled” athletic bodies. Weight loss is associated with success and determination. Social media reinforces the notion that thinner is better. We see athletes in top form that is short-lived and sometimes unhealthy.

Thinner works, but only up to a point.

Elite athletes reach about 6-10% male / 16-19% female body fat levels in their competition period. But that is not how they look the whole year. Quite the opposite. An athlete’s body changes over the course of the year.
The most important factor for an athlete is to be able to train. If you are getting injured often, lack energy for your training sessions and feel less than good most of the time, your performance will deteriorate. Higher body fat levels, 10-12% for men and 15-20% for female athletes, are typically sustainable without much effort.
Keeping a slightly higher body fat percentage also allows athletes to prevent injuries, and getting ill, and keep training and improving.
Since 2019, we have seen several high-performing athletes come out and share their stories about how chasing leanness hindered their health and performance. Amelia Boone, 3x winner of the World’s Toughest Mudder (2012, 2014, 2015), Spartan Race World Champion 2013, Spartan Race Points Series Champion (2013 & 2015), 3x Death Race Finisher (Winter 2012, Summer 2012, Summer 2013) is just one example.

What do studies say?

One study on amateur runners (men) looked at the association between body fat percentage and marathon completion time.

The sample of runners was quite diverse:

  • The average % fat of the runners was 16% (range 8-25%).
  • Age ranged from 18 to 72 years.
  • Running speed in training sessions ranged from 7.7 to 15.5 km/h.
  • Number of years trained from 0.5 to 35 years.

What did they find?

17-18% body fat appears to be the threshold, according to this study, where body fat starts to be a hindrance to performance. At lower body fat percentages, running performance was related to the number of miles run per week, days trained, and pace during their pre-marathon runs.


Some people naturally have more body fat, differently distributed body fat, and % body fat alone is not indicative of overall body condition.

“But after all, lighter runners run better! Look at the Ethiopian runners!”

Losing weight will improve performance in runners who have excess body fat, but trying to lose the last 2-3kg before a race doesn’t help. Not even for elite athletes.

Recently a study came out on 23 elite race-walkers that had a high rate of control. From their training to body composition measurements to food.

Over the course of 9 days, the walkers were divided into two groups. A control group and a weight loss group. After 9 days, both groups had a day where they replenished their energy and glycogen stores. This was followed by a 10km race.

The results?

Both groups improved their performances over the 9 days.

Control group

  • their weight changed minimally
  • Improved performance by 4.5% ± 4.1%, approx. 127s.

Weight loss group:

  • They lost approx. 2kg (1.6kg body fat) – 3% of their total body weight
  • improved performance by 3.5% ± 1.8%, approx. 92 s.

Another study on 50 elite cyclists showed:

  • All riders believed that achieving a minimum body weight, especially a low percentage of body fat, should be critical for maximal performance. However, there was no significant correlation between body fat percentage and performance (!)
  • Cyclists with chronically low caloric intake did have lower % body fat, but they also had reduced performance at higher training loads, lower testosterone levels, and lower bone density!

What to take from this?

Even if we assume that a relatively lean runner would reduce weight, it is unlikely to help him or her significantly improve performance. Realistically, when losing weight, not only is fat lost, but muscle mass, water and glycogen stores are lost at the same time! This may ultimately have a greater negative effect than the potential benefit of a small weight loss.

A lighter runner is not necessarily a better one. Dropping the last 2-3 kg will not add to performance, while the weight loss itself may worsen overall performance.

Maybe that’s why we see carb-loading before a marathon and not weight-cutting like in MMA or bodybuilding 😉 .

For relatively lean athletes, it’s important to focus on training, not trying to drop 1% fat at any cost.

Focus on performance! This can mean increasing strength, and muscle mass, improving overall nutrition, fueling, and sleep.

Megan Markoff, CrossFit athlete

Megan Markoff, a CrossFit athlete and a coach, shared her story on IG and allowed me to share her photos with you. She described how her body changed over time and when she was her leanest, she was not happy and she was fighting with low energy
In 2014, I found CrossFit and immediately wanted MORE. I wanted to lift more and perform better, but I had absolutely no idea how to fuel my body.
In 2017 she and other two girls qualified in an Elite Team to compete at Wodapalooza in 2018.
In 2018, she was eating about 2700kcal but that was still not enough to keep her body healthy. She had visible abs but she was struggling with sleep, no sex drive, low energy and extreme anxiety. She was obsessed with staying that lean.
After that, she decided to work on her relationship with her body and committed to putting her health first, which meant gaining some weight over time. But two years later, she is better off and she is at the level of leanness that is sustainable for her.
Remember. Bodies were meant to change. I know mine will change again this year. It’s ok if your body has changed. What always needs to come first is your health. And health means your physical and mental health too.

The Trade-offs

Your ideal racing weight would be the perfect balance between having enough muscle to generate power and having low amounts of excess weight to make you most efficient.
If your goal is optimal performance, you need to realize there are trade-offs between power, fat mass, muscle mass and endurance.
In hybrid sports such as CrossFit, Hyrox, Spartan Race it is a trade-off an athlete needs to make, which can be challenging for their mind.
If you are a CrossFitter deadlifting over 500lb, you might need to lose some weight to run faster, more efficiently, and improve your endurance. Lowering your maximal lifts can lead to improvments of your overall performance.
If you are a lean runner, you might need to gain muscle, eat more, and therefore gain weight to run injury free, faster, and more efficiently. Your weight might go up, your 5k time decrease, but your overall performance increase.
The problem is that athletes don’t want to lose their hard-earned performance. Psychologically, we are more motivated by “avoiding loss” (losing something you have) than by “potential gain” (getting what you don’t have).
If you are married to your current weight, training and approach, it will be a mental challenge. Working with a coach in a situation like this is a huge help.
It is important to find your ideal racing weight. In the Spartan Race, it can differ between distances Sprint, Super, Beast , UB and Trail.
hunter mcintyre

Hunter McIntyre – example

Hunter McIntyre is a 6-time obstacle course racing (OCR) world champion, 4-time OCR national champion, the reigning Broken Skull Ranch champion (the television show hosted by Stone Cold Steve Austin), the 2017-2018 Tough Mudder X Champion, and holds multiple HYROX world records.
When he was training for HYROX world championships, he wanted to maximize his performance. He did not need 500lb, nor run 4 minute mile, because it was not specific for the event. He needed the right combination of strength and speed.
Now that he is training for Spartan Race again, he is intentionally losing muscle mass so he can be more efficient runner while keeping enough strength for the obstacles.

How to find your ideal racing weight?

Your ideal racing weight would be the perfect balance between having enough muscle to generate power and having low amounts of excess weight to make you more efficient.
If you have some weight to lose, you will find that as your weight decreases to a certain point, your performance will be increasing. From a certain point, once you get lean enough, your performance will begin to decline rapidly.
The weight is made up of not only fat, but also muscles, bones, glycogen and water. Fat is necessary for the proper function of the hormonal system and it also serves as a buffer in crashes and keeps you warm.
For lighter runners, I often see how gaining weight (especially muscles) improves their overall health and performance.
Start noting  your body weight/composition and how it correlates with your performance. You cna track your running pace, weight and strength and over time find your ideal ration.

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