If you attend marathons, you might wonder, “why are marathon runners so skinny?” It’s not that only skinny people run; marathoners have their physiques for a reason.
Have you ever been at a race and looked around you and wondered why are marathon runners so skinny? It has to do with caloric intake vs. caloric expenditure, genetics, and the kind of training marathoners typically do. Let’s go in-depth to explore why long-distance runners are so thin. Learn more in our marathoner vs. sprinter body guide.
Contents
Why Marathon Runners Are Skinny
1. Genetics
Regardless of how much strength training they do, many runners have a hard time putting on weight. A lot of this has to do with genetics. If an individual is genetically predisposed to be on the thin side, it will play a role in trying to gain weight.
2. Many Marathon Runners Have Insufficient Caloric Intake
Running burns enormous amounts of calories. The American Council on Exercise has determined that runners burn more calories per minute than athletes who do any other type of exercise. Doing a bit of math, you can see those elite runners burn nearly 2,000 calories per marathon – the average person would still burn quite a lot, too, during a marathon.
Most Americans eat about 3,600 calories daily, and it’s easy to see that if someone runs most days, they burn a lot of calories every week. Certainly, one marathon won’t make a person skinny, but a lot of training and miles leading up to that event.
3. Most Marathon Runners Don’t Have Time For Strength Training
Maraton training is long and vigorous, so many athletes neglect full-body strength training when they’re preparing for a marathon. It’s particularly time-consuming and challenging to do a daily strength-training session when you’re trying to get those miles on the pavement.
For this reason, most marathon runners focus on the aerobic aspect of running because this is what is most important for long-distance running. Keep in mind that besides running, most marathoners also have full lives that include work, family, and social activities. If you don’t want to be skinny, you have to find a way to pair some strength training with your running.
4. Protein Breakdown Causes Muscle Loss
When you run a lot, the duration of prolonged exercise sometimes leads to a decreased testosterone level and protein breakdown. Protein breakdown occurs when two things happen:
- Insufficient fat and glycogen stores in the body
- Increased cortisol levels
While you’re running, the body gets most of its energy from the glycogen that’s stored in your muscles. After about 90 minutes of moderate-intensity exercise, your body will switch to the body’s fat stores, which will usually burn long enough for you to finish your run.
When runners fail to replace the glycogen stores that have been depleted, the only way the body can burn fuel is to use protein as the source. When this happens, your body is burning muscle, and that’s one thing that makes runners look skinny. You might be interested in learning why is a marathon 26.2 miles.
How Much Should Marathon Runners Weigh?
The optimal weight for male elite marathoners is between 120 and 126 pounds. For example, former marathon world record holder Patrick Makau Musyoki weighed 121 pounds at his peak. The average weight for female elite marathon runners is between 93 and 119 pounds. Elite marathon runner Brigid Kosgei is 5’7″ tall and weighs 110 pounds.
FAQs About Why Are Marathon Runners So Skinny
Are Marathon Runners Always Thin?
Technically, you can run a marathon at any weight as long as your body holds up for the challenge. However, elite long-distance runners are nearly always thin. Muscle bulk slows down their running time.
Does Long-Distance Running Make You Skinny?
Yes, long-distance running will make you lose weight because you burn a lot of calories when you’re physically active for that long. However, the word “skinny” is inaccurate for describing marathon runners. More accurately, marathon runners are incredibly lean, not skinny.
Are Skinnier Runners Faster?
Elite sprinters have the genetics to be muscular, strong, fast, and powerful. To be a fast runner, you have to have more muscle tissue because you need a high knee thrust and a powerful arm pump. In short, fast runners need well-developed quads, hamstrings, glutes, shoulders, arms, chest, and backs.
