Cutting Weight Diminishes Athletic Performance in Women: Study

Introduction

A new scientific study has found that ‘cutting weight’, or sudden, deliberate weight loss, may have detrimental effects on athletic performance. This may not be surprising news to many–so why is the practice so common in so many sports?

The Prevalence of Weight Cutting in Sports

If you’re a professional athlete, or even an amateur athlete, you may be familiar with the practice of losing weight before a performance. Sports in which this practice is especially prevalent include endurance sports, such as long-distance running, and also martial arts, swimming, bodybuilding, and others. The prevalent thought is that by quickly losing weight before a competition or performance, and in some cases, ‘re-feeding’ right before, an athlete can ‘boost’ their abilities, making them lighter, faster, stronger, etc. And while this approach is widely accepted in athletics, it can also have some pretty detrimental effects on your health.

The Study and Its Findings

A recent study done at the University of Copenhagen found the detrimental effects of cutting weight to be demonstrated especially in women. The study recruited twelve female triathletes, all of whom had a ‘normal’ energy intake. For two weeks, the participants maintained their normal caloric intake, after which their performance was tested. After that, the researchers cut the participants’ calories by 50% for two weeks, and the participants maintained their normal intensive training schedule. During the two weeks in which their calories were restricted, the athletes lost about 4% of their body weight, half of which was muscle mass, and they also experienced a loss in performance–and the performance loss was quite marked. In a 20-minute time trial on a bike, the participants were nearly 8% slower, and in another short-term test, their performance was diminished by almost 18%.

Other Detrimental Effects

Other detrimental effects included an increase in cortisol and a lowering of immune system function. The researchers also noted that a ‘re-feeding’ period of three days, in which participants’ energy levels were restored, didn’t drastically improve their performance or bring it back to baseline; their performance was just as degraded as before. This type of deprivation and re-feeding protocol is very common in elite athletics with the thought that an intense period of ‘re-fuelling’ will dramatically improve an athlete’s performance. But, as this study demonstrates, this protocol may not only be ineffective but harmful.

Implications for Female Athletes

So, what does this mean for sports performance? This research, along with other research done on the topic, has led many experts to hypothesize that female athletes are unlikely to benefit from cutting. Estrogen levels are especially sensitive to energy deprivation, a hormone essential for women’s health and that can detrimentally affect the circulatory system, muscle and bone health, and more.

Recommendations for Safe Weight Management

If you’re an athlete and you’re intent on cutting weight, there are some generally recommended protocols. Some recommendations include eating enough protein, cutting down on sugar, refuelling adequately after a workout, and not cutting for longer than needed. If possible, speak to an expert on the subject, such as a sports nutritionist, and make a plan that will not only improve your performance but protect your long-term health.

Share Your Experience

Do you have experience in cutting weight, and have you found it to be beneficial for your performance? We’d love to hear from you! Share your thoughts and experiences in the comments below.

Conclusion

While cutting weight is a common practice in many sports, recent research indicates that it may do more harm than good, particularly for female athletes. Understanding the potential risks and seeking professional guidance can help athletes make informed decisions that prioritize both performance and long-term health.

Wishing you all the best on your journey to optimum health!

​​Written by Theresa Faulder, Master’s in English, Certified Personal Trainer and Infofit fitness blog writer.

                                                            Works Cited

1. Jan S. Jeppesen, Hannah G. Caldwell, Lone O. Lossius, Anna K. Melin, Lasse Gliemann, Jens Bangsbo, Ylva Hellsten. Low energy availability increases immune cell formation of reactive oxygen species and impairs exercise performance in female endurance athletes. Redox Biology, 2024; 75: 103250 DOI: 10.1016/j.redox.2024.103250