A recent meta-analysis has delved into the potential benefits of combining intermittent fasting with exercise to promote weight loss. Conducted by analyzing 15 separate studies, this research aimed to understand how these two popular health strategies might work together to enhance body composition. The participants, primarily young adults with an average age of 29, engaged in exercise during specified eating windows, revealing interesting insights into the effectiveness of this approach.
The study incorporated a variety of experimental designs, including randomized crossover studies and randomized controlled trials. These investigations lasted for at least four weeks, with some extending beyond 12 weeks. Participants' body mass index (BMI) ranged mostly in the normal to overweight categories, with thirteen studies focusing on individuals with BMIs of 25 or less. The exercise routines varied, comprising aerobic exercises, resistance training, or a combination of both, all performed within the designated eating periods.
“while [time-restricted eating] with exercise could complement weight management strategies, its application must be individualized.” – Ryan Glatt, CPT, NBC-HWC
In most studies, the participants adhered to an eating window primarily set between noon and 9 p.m., though variations existed. The results indicated a modest reduction in body fat percentage by 1.3% and a decrease in fat mass by 1.3 kg. Despite these findings, the researchers noted that factors such as BMI, exercise type, age, energy intake, and the duration of the study did not significantly impact the results. However, the diversity in study design may have influenced the overall outcomes.
“Evidence remains inconclusive about whether [time-restricted eating] offers advantages over traditional calorie control and regular exercise routines. More rigorous, controlled trials are needed to confirm the effectiveness of [time-restricted eating] with exercise, particularly in diverse populations. Studies should also examine long-term adherence and real-world feasibility, as these factors heavily influence outcomes in practical settings,” – Ryan Glatt, CPT, NBC-HWC
The limitations of the meta-analysis were evident in several aspects. All included studies were written in English and focused exclusively on healthy adult participants, excluding those with conditions such as cardiometabolic disorders. Additionally, nine of these studies comprised solely male participants, potentially limiting the applicability of findings across genders. The data collection methods and inclusion criteria further constrained the scope of the analysis.
“you’d think that the average BMI [of the participants] would be in the overweight to obese category.” – Kalyn True, RDN, LD
Despite the intriguing findings, experts urge caution in interpreting the results. The relatively short duration of many studies—six lasted for just four weeks, while only one extended beyond 12 weeks—suggests that longer trials might be necessary for more comprehensive insights. Furthermore, experts emphasize that significant body composition changes typically require at least 12 weeks to manifest.
“typically, it will take at least 12 weeks to see proper body composition changes regardless of time-restricted eating.” – Kalyn True, RDN, LD
Leave a Reply