Can creatine and resistance training trim your body fat percentage?

By Vijay Kumar MalesuOct 16 2023Reviewed by Benedette Cuffari, M.Sc.

In a recent study published in the journal Nutrients, researchers investigate the impact of resistance training combined with creatine supplementation on body fat percentage and absolute fat mass in adults under 50.

Study: Resistance Exercise and Creatine Supplementation on Fat Mass in Adults < 50 Years of Age: A Systematic Review and Meta-Analysis. Image Credit: Halk-44 / Shutterstock.com

Background 

The rise in young adult adiposity poses risks for future chronic conditions like obesity and diabetes, thus underscoring the need for lifestyle interventions to manage fat mass for long-term health.

Creatine supplementation, combined with resistance exercise, has shown promise in older adults; however, its efficacy in those under 50 remains uncertain, as researchers have raised concerns that creatine might increase fat. Thus, further research is needed to understand the specific effects of resistance exercise combined with creatine supplementation on fat mass in adults under 50.

About the study

The present study strictly adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards and had its protocol registered in the International Prospective Register of Systematic Reviews (PROSPERO) database. Reviewers independently searched databases like Scopus, PubMed, Web of Science, and the Cochrane Library to identify relevant studies from inception until April 2023.

The searches focused on terms related to creatine supplementation and body composition. Studies were selected based on specific inclusion criteria such as the type of trial, participant age, nature of interventions, methods of body fat assessment, and minimum study duration, without language restrictions. Certain studies were excluded, including those that were not randomized controlled trials (RCTs), only provided an abstract, involved dietary restrictions, or featured overlapping populations with other studies.

During data extraction, various details were recorded, ranging from basic study information to specific outcomes and methods. A third investigator resolved any disagreements in data extraction. The Cochrane risk-of-bias tool (RoB2) was utilized to assess the quality of the studies and focused on multiple domains of potential bias in the trials.

For the statistical analysis, the researchers calculated mean differences and employed standardized mean differences for inconsistent units across studies. The random-effects model and inverse-variance approach were utilized in analyzing the data.

The consistency of the studies' results was assessed using statistical heterogeneity measures. Subgroup analyses based on various factors such as sex, age, assessment tool, body mass index (BMI), creatine dosage and duration, and exercise frequency were also performed.

Sensitivity analyses were performed to ascertain the reliability of the statistical outcomes. All meta-analyses were conducted using Cochrane's Review Manager software.

Study results

This comprehensive literature search initially yielded 3,028 publications. After eliminating 486 duplicates, 2,542 unique publications remained. Moreover, 2,134 studies were immediately excluded based on their titles and abstracts for not meeting the eligibility criteria.

Further scrutiny led to the elimination of an additional 376 publications due to irrelevant study designs and outcomes. This led to a total of 32 RCTs that investigated the effects of creatine monohydrate on body fat in individuals under 50 years of age.

However, several of these RCTs were also excluded for various reasons. For example, some used skinfold calipers for fat measurement. Some studies did not incorporate resistance training with creatine monohydrate, some studies had a treatment duration of fewer than four weeks, while others used certain methodologies or lacked comprehensive data.

Ultimately, 12 RCTs qualified for inclusion in the systematic review and meta-analysis. These studies comprised 266 participants divided almost equally between the creatine and placebo groups.

While creatine supplementation did not significantly alter absolute fat mass over time, it did result in a notable reduction in body fat percentage. Subgroup analyses indicated that this effect was consistent across various categories, including creatine dose, age, fat mass assessment tool, BMI, sex, supplementation duration, and resistance exercise frequency. No significant differences were evident, thus suggesting that creatine's impact on body fat percentage was relatively uniform across these diverse conditions.

Sensitivity analyses were conducted to ensure the robustness of these findings by accounting for participants' health conditions, dietary intake assessment in the studies, and the potential risk of bias within the studies themselves. These analyses affirmed the primary findings and indicated no significant deviations or concerns that might undermine the conclusions drawn from the main analysis.

In assessing the risk of bias within the included studies, most studies exhibited low to moderate risk, with only two studies presenting a high risk. Concerns predominantly stemmed from insufficient details about the randomization and treatment allocation processes.

More specifically, two studies did not specify if participant randomization occurred, whereas another was conducted in a single-blind manner, potentially introducing bias. These evaluations of bias risk, which are integral to ensuring the reliability and validity of the systematic review, were thoroughly documented and visualized for clear representation and understanding.