The Most Dangerous Running Advice I Read This Week

Every once in a while, I read something on social media that makes me stop scrolling.

Last week was one of those times.

Someone forwarded me an Instagram post that read, "Hot take: The lighter you are, the faster you are."

Normally, I don't comment on posts I disagree with. Maybe it's because I don't enjoy conflict. Maybe it's because there are simply too many opinions on the internet to chase down. But this one genuinely made me angry because it was so irresponsible.

Over the last decade, we've made tremendous progress in understanding Relative Energy Deficiency in Sport (REDs) and Low Energy Availability (LEA). Professional and amatuer runners have bravely shared stories about the pressure they faced from collegiate and professional coaches, social media or even teammates to lose weight, only to watch their health, careers, and performance fall apart. Stress fractures. Hormonal dysfunction. Chronic fatigue. Recurrent injuries. Burnout.

These aren't isolated stories anymore. They're well documented.

Every day, clinicians, dietitians, coaches, researchers, and medical teams—including our team at Precision Performance & Physical Therapy and the medical staff for Atlanta Track Club Elite—work to help athletes stay healthy, adequately fueled, and performing at their highest level. We spend countless hours educating runners that eating enough isn't just important for health but it's also essential for performance.

Then a post like this shows up and reduces running success to a number on the scale.

Here's the truth: body weight is only one small piece of the performance puzzle.

Can excess body mass influence running economy? Of course. But that's very different from telling runners that lighter is always faster. The human body doesn't work that way.

Muscles need energy to adapt. Bones need energy to remodel. Hormones need energy to function normally. Your immune system, recovery, sleep, and ability to handle training all depend on having enough fuel.

The fastest runners in the world aren't always the lightest. They're the athletes who can train consistently, recover well, stay healthy, and absorb years of quality training.

Ironically, many athletes who intentionally underfuel may perform well for a while. Early on, they may even feel faster as their weight drops. But eventually the bill comes due. Injuries become more frequent. Recovery slows. Performance plateaus or declines. Many never get the opportunity to discover what they were truly capable of because their bodies broke down first.

If you've followed my writing for any length of time, you've probably heard me talk about REDs before. BUt just in case you need a reminder.

Low Energy Availability happens when your body doesn't have enough energy left over after training to support normal physiological function. REDs is the collection of health and performance consequences that follow. It doesn't just affect female athletes. It affects men and women, elite runners and recreational runners alike.

The signs can be subtle: declining performance, recurrent injuries, frequent illness, poor recovery, disrupted menstrual cycles, low testosterone, mood changes, or persistent fatigue. Left untreated, the consequences can be significant.

So the next time you see someone confidently telling runners that lighter is always faster, ask yourself one question:

What qualifies them to give that advice?

A catchy social media post doesn't outweigh decades of sports medicine research.

Don't confuse being lighter with being healthier. And don't sacrifice long-term performance chasing a lower number on the scale.

The goal should not be to be the lightest runner you can be.

Healthy means becoming the strongest, most resilient, best-fueled runner you can be so you can reach your full potential.