Congratulations to Mojir Muhajir, OMS-III, the second-place winner of the Namey/Burnett Award for 2025! Sponsored by the ACOFP Foundation, the Namey/Burnett Preventative Medicine Writing Award honors the memory of Joseph J. Namey, DO, FACOFP, and John. H. Burnett, DO, FACOFP, who were both dedicated advocates for osteopathic medicine. This award recognizes the best preventive medicine scientific writings submitted by osteopathic family medicine students and residents.

Abstract

The escalating global obesity crisis is intricately linked to sedentary behaviors, which significantly impede effective weight management. Despite the widespread adoption of weight-loss interventions, inadequate physical activity remains a persistent barrier to achieving sustained outcomes.3,4 This paper explores the nexus between physical inactivity and the challenges of weight loss, with a particular focus on the application of Metabolic Equivalent of Task (MET) scores as a methodologically robust tool for optimizing exercise regimens. By systematically quantifying energy expenditure and facilitating individualized physical activity planning, MET scores emerge as a critical asset in addressing weight-loss plateaus and enhancing metabolic health.

Introduction

Obesity and its associated comorbidities, including type 2 diabetes, hypertension, and cardiovascular disease, represent a profound public health challenge. Although dietary modifications dominate contemporary weight-loss strategies, the pivotal role of intentional exercise should not be underestimated. The pervasive adoption of sedentary lifestyles,4,5 characterized by prolonged inactivity and insufficient aerobic exercise, exacerbates weight gain and undermines the efficacy of caloric restriction interventions. Addressing these deficiencies requires a comprehensive framework that integrates structured physical activity into weight-loss paradigms.

Exercise contributes to weight loss through direct caloric expenditure and by augmenting metabolic efficiency. Nevertheless, a substantial proportion of the population fails to meet the recommended threshold of 150 minutes of moderate-intensity aerobic activity per week, as outlined by the World Health Organization (WHO).1 This deficiency curtails energy expenditure, compromises lean muscle mass, and diminishes basal metabolic rates—all factors that increase the difficulty of achieving sustained weight loss.

Surveys indicate widespread frustration regarding the ineffectiveness of exercise for weight loss. For instance, a study by Thomas et al. (2015) published in Preventive Medicine found that 71% of respondents believed exercise to be a very effective weight-loss strategy, yet many became discouraged when expected results were not achieved.6 Can utilizing MET scores provide real time data to individuals to assist in optimizing weight loss?

Understanding MET Scores

The Metabolic Equivalent of Task (MET) provides a standardized metric for quantifying the energy demands of various physical activities. One MET corresponds to the resting metabolic rate, defined as approximately 3.5 mL of oxygen consumed per kilogram of body weight per minute. Activities are assigned MET values proportional to their intensity; for example, walking at a moderate pace (3.5 miles per hour) is assigned a MET value of 4, whereas running at a speed of 6 miles per hour is assigned a MET value of 10.2 By translating physical activity into quantifiable metrics, MET scores facilitate precise calculations of energy expenditure and enable tailored exercise prescriptions.

Methods

The optimal metabolic equivalent of task (MET) for burning fat during exercise is closely related to the exercise intensity that elicits maximal fat oxidation (Fatmax).  According to the study by Achten et al., maximal fat oxidation occurs at approximately 64% of VO2max, which corresponds to about 7 METs for a moderately trained individual (assuming 1 MET = 3.5 mL O2/kg/min). This intensity is also equivalent to 74% of maximal heart rate (HRmax).9

Incorporating MET scores into weight-loss regimens empowers individuals to make informed decisions about their physical activity by enabling personalized estimations of caloric expenditure based on body weight and activity type. For instance, a 70-kg individual walking at a 4-MET intensity for 30 minutes expends approximately 140 kcal (70 kg × 4 METs × 0.5 hours). Additionally, MET values facilitate strategic goal setting by aligning targeted caloric expenditure goals with individual energy balance objectives. The quantitative feedback provided by MET scores further enhances motivation by encouraging engagement in higher-intensity or prolonged activities, amplifying caloric expenditure and fostering adherence to exercise routines.

For weight loss, the American College of Cardiology and the American Heart Association suggest higher doses of physical activity, such as expending 2,500 kcal/week, which corresponds to approximately 35.7 MET-h/week for a 70-kg individual, may be more effective than lower doses.7 

In individuals with obesity, Dandanell et al. found that maximal fat oxidation occurs at a lower intensity, around 42-45% of VO2max, which would correspond to approximately 4.5-5 METs.8 This suggests that the optimal MET for burning fat can vary based on an individual's fitness level and body composition.

Overall, for most individuals, the optimal MET for burning fat during exercise typically ranges from 4.5 to 7 METs, depending on their fitness level and body composition. This range allows for high rates of fat oxidation while maintaining a sustainable exercise intensity.

One method to easily determine if an individual is exercising to the required intensity is by measuring the calories burned after each exercise. Based on the 2011 compendium of physical activity, an uphill walk has a MET score of 5.3. That means for an individual who weighs 70 kg, 1 hour of uphill walk should cost 371 calories if they want to optimize their weight loss from that activity. The calories burned can be easily measured by most smartwatches for fitness trackers and can provide quick feedback to individuals if they are using their exercise to maximum.

Discussion

Empirical studies underscore the efficacy of MET-informed exercise interventions in facilitating weight loss. For instance, randomized controlled trials have demonstrated that participants who incorporated MET-based targets into their fitness regimens achieved superior weight-loss outcomes compared to those following generalized activity guidelines.2,3 Furthermore, the integration of MET scores into structured group exercise programs has been associated with higher adherence rates and improved cardiovascular fitness.3

Despite the demonstrable utility of MET scores, several barriers hinder their widespread implementation. These include limited public awareness, the perceived complexity of energy expenditure calculations, and disparities in access to fitness resources. Healthcare professionals and fitness practitioners are integral to bridging these gaps by educating patients and clients on the practical applications of MET scores. Additionally, advancements in wearable technologies and mobile applications offer promising avenues for real-time MET-based feedback, enhancing accessibility and user engagement.

Conclusion

The persistent lack of exercise constitutes a formidable obstacle to effective weight management. Leveraging MET scores as a framework for optimizing physical activity presents a scientifically grounded strategy to overcome these challenges. By enabling precise quantification of energy expenditure and fostering individualized exercise plans, MET-based approaches hold significant promise for enhancing weight-loss efficacy and promoting long-term metabolic health. Future research should prioritize the development of accessible tools and methodologies to integrate MET scores into diverse clinical and community settings.

References

  1. World Health Organization. Physical activity and adults: recommended levels of physical activity for adults aged 18-64 years.https://www.who.int/news-room/fact-sheets/detail/physical-activity. Accessed 1/10/25].
  2. Ainsworth BE, Haskell WL, Herrmann SD, et al. Compendium of physical activities: classification of energy costs of human physical activities. Med Sci Sports Exerc. 2011;43(8):1575-1581. Doi: 10.1249/MSS.0b013e31821ece12
  3. Jakicic JM, Rogers RJ, Davis KK, Collins KA. Approaches to physical activity for weight loss: toward evidence-based recommendations. Obesity (Silver Spring). 2018;26(1):14-22. doi:10.1373/clinchem.2017.272443
  4. Lee IM, Shiroma EJ, Lobelo F, et al. Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. Lancet. 2012;380(9838):219-229. Doi: 10.1016/S0140-6736(12)61031-9
  5. Church TS, Thomas DM, Tudor-Locke C, et al. Trends over 5 decades in U.S. occupation-related physical activity and their associations with obesity. PLoS One. 2011;6(5):e19657. Doi: 10.1371/journal.pone.0019657
  6. Thomas DM, Kyle TK, Stanford FC. The gap between expectations and reality of exercise-induced weight loss is associated with discouragement. Prev Med. 2015;81:357-360. doi:10.1016/j.ypmed.2015.10.001
  7. American College of Cardiology/American Heart Association Task Force on Practice Guidelines, Obesity Expert Panel, 2013. Expert Panel Report: Guidelines (2013) for the management of overweight and obesity in adults. Obesity (Silver Spring). 2014;22 Suppl 2:S41-S410. doi:10.1002/oby.20660
  8. Dandanell S, Præst CB, Søndergård SD, et al. Determination of the exercise intensity that elicits maximal fat oxidation in individuals with obesity. Appl Physiol Nutr Metab. 2017;42(4):405-412. doi:10.1139/apnm-2016-0518
  9. Achten J, Gleeson M, Jeukendrup AE. Determination of the exercise intensity that elicits maximal fat oxidation. Med Sci Sports Exerc. 2002;34(1):92-97. doi:10.1097/00005768-200201000-00015
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