Movement sparks progress. For high performers, this forward momentum is powered by currents in science, technology, and subculture. To celebrate the launch of ASICS GEL-NIMBUS® 21, Furthermore and ASICS have partnered to harness the power of these currents and show you how to channel them and turn them into actual results.
It’s not complete B.S. Many runners perform well with a body fat percentage on the lower side—around 16 percent for women and 10 percent for men, says Rob McCabe, Tier X manager at Equinox Kensington in London. David Siik, LA-based senior manager of running for Equinox and creator of Precision Run, adds that especially for longer distances, having less excess weight can theoretically help you move more efficiently.
But athletes and coaches are recognizing you can’t, and shouldn’t, shrink yourself toward PRs or onto podiums. Siik knows this firsthand: He ran his fastest at his leanest, but the changes he made to get there weren’t sustainable and caused unwanted side effects, like trouble focusing.
That said, being lean shouldn’t be the top priority. Here’s how you can apply the latest thinking about body mass and running performance to reach your own goals.
How you look isn’t always a reliable indicator of body composition, says Cynthia Barrett, a Precision Run instructor at Equinox locations in New York City.
Advanced tools that evaluate body comp (the percentages of fat, bone, muscle, and water in your body) often prove visually “big” people have more lean tissue powering them forward than you’d think, she explains. It’s just distributed differently. On the flip side, “people who are lean may not be as fit as we think that they are,” she says. You don’t have to “look like” an endurance runner to be one.
Even if losing fat quickly speeds you up in the short term, you’ll eventually pay the price in injury and hormonal disruptions if you take it too far, McCabe says. When lighter does equal faster, it’s not only due to physics. It’s because the changes the runner made to lose fat (like prioritizing sleep or choosing carbs wisely) improved their overall health, Siik says.
In the end, it’s not just about body fat. “Being a healthy weight can add years to your career and allow you to reach higher levels, while short-term starvation will give you rapid results that don’t last,” says elite runner, coach, and Olympian Ryan Hall, whose 2:04:58 marathon PR is the fastest-ever for an American athlete.
Every body is different. Your friend might get lean and speed up, but you may do the same thing and end up with fatigue and injury. “Don’t compare your height or weight to other runners,” Hall says. “Bad things happen when we try to be someone we are not.” He suggests you find your ideal body comp based on where you feel strongest and perform your best.
Leaning out requires a caloric deficit, which adds stress to your body. If you have body comp goals, set aside a block of time during the off-season to focus on them—preferably with the guidance of a Tier 3+ trainer or Tier X coach, all of whom are Precision Nutrition-certified. Then, ramp up your mileage once you’ve reached your goals.
If you think you’ve aced your nutrition and still hit a plateau, you might actually need to eat more calories, not fewer. McCabe recalls one ultrarunner he worked with who didn’t lose fat or improve until she upped her intake.
For elite runners, recreational joggers, and everyone in between, body mass is just one piece of the performance puzzle. The right training and nutrition plans, cardiovascular fitness, strength, flexibility, and recovery should be top priorities. “A lot of runners could probably get healthier and faster by stretching more or getting one more hour of sleep a night,” Siik says. Speed also comes from mental training, especially when you’re running longer distances, Barrett says. Sticking to your plan even when you don’t feel like it builds confidence and grit that can help you take each workout to the next level—and execute when it counts on race day.