Article Highlight | 5-Feb-2024

Running won’t help lose weight, but it does prevent weight gain 

University of Jyväskylä - Jyväskylän yliopisto

Recently, some media outlets have highlighted that it is a myth that running will help you lose weight/fat. There is certainly convincing scientific evidence that after an initial loss in fat mass from engaging in an exercise regime, the body lowers its overall energy expenditure to conserve energy and ultimately its fat mass stores. This is nature’s insurance policy developed by our ancestors to prevent starvation during times of restricted food availability. A new study, however, showed that running prevents increases in body fat in the long-term.  

Don't be discouraged if, after a promising start, you can't get your weight down by running. Recent work from the University of Jyväskylä ( has shown that running helps to prevent weight or fat gain in those that continue to run. Hopefully this helps to maintain motivation throughout the up-coming months once the fast gains have waned.  

“Our data clearly shows that lifelong running exercise, be it long-distance or repeated short-distance sprinting, maintains lower fat mass levels than a typical physically active lifestyle and also more than participating in competitive strength sports.” says Dr. Simon Walker, a Docent in Exercise Physiology from the Faculty of Sport and Health Sciences.  

The older sprinters and endurance athletes in the study even had lower fat mass than young strength athletes and physically active controls.  

“Absolutely this result motivates me to continue running. I’d certainly be happy with a fat percentage of 16–18% when I’m in my 70s and 80s”, continues Dr. Walker. 

Lifelong strength training is best for maintaining muscle mass 

The same study showed that individuals participating in lifelong resistance training maintained muscle mass better than those competing in sprint and long-distance running sports. Additionally, the older strength trainers had a similar amount of muscle mass as their young counterparts.  

Dr. Walker suggests a combined training approach may be most beneficial for optimizing body composition throughout the lifespan: 

“In terms of enhancing body composition through both heightened muscle mass and maintenance of a non-health affecting fat mass, it seems that a combined approach is recommendable. We know that both tissues, fat and muscle, influence overall health and function opposingly. Therefore, the best strategy would be to optimize both.  

Walker suggests that two-to-three sessions of endurance and the same for resistance exercise (i.e. 4–6 sessions per week), depending on your preference, mood, motivation, or taking into account seasonal variation should lead to the same kinds of results seen in the athletes in the study.  

“The key is perhaps to prevent a rise in fat mass or loss in muscle mass in the first place and maintain exercise throughout the lifespan. Thus, lifelong engagement in regular exercise does help to maintain a healthy body composition. That is no myth.” 

The present study was performed using data from larger cohort studies (ATHLAS and CALEX-family cohorts) led by Dr. Marko Korhonen and Emer. Prof. Sulin Cheng, respectively. It includes males aged 20–39 and 70–89 years who were competitive sprinters, endurance runners and strength athletes, and also controls who were physically active but did not compete in sports. 

“While we studied males only, I see no reason why our results would not be applicable for females too, especially considering the effects of menopause and other age-related effects.” 

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