Fat-burner walks: Do they really burn more fat?
Have you heard of a fat burner walk? I’ve certainly seen people promoting or participating in this “weight loss hack” on Instagram and I was curious about whether or not this was actually a worthwhile fitness trend to jump on board with. I’m not a morning person so the thought of getting up early and going for a walk before I eat breakfast is not very inviting to me. Whilst this may be something you participate in naturally and don’t consider it to be for any other reason than to start your day off right, you may have been lead to believe that this is a necessary part of your daily routine to shed those stubborn kilo’s.
For those who may not know, the “fat burner walk” trend refers to: going for a walk in the morning prior to eating to burn more body fat. It is suggested that undertaking cardio after fasting overnight increases the use of stored fat as fuel due to a limited amount of available carbohydrates available to provide energy (1). Whilst this sounds plausible, what does the science actually tell us?
Let’s Talk Science
A systematic review and meta-analysis was completed in 2017 by Hackett and Hagstrom (2). They analysed five different studies who all investigated healthy adults comparing effects on body mass/composition following exercise in both fasted and fed states. Effects on body fat percentage measured in females was not significantly different between the two groups. This was not a measure used in studies with male participants.
This study concluded that the research does not support the use of participating in exercise in a fasted state in order to lose weight. Whilst it has been found that there is an increase in fat oxidation post fasted exercise when compared with exercise post a carbohydrate meal (3), there is limited evidence as to whether this influences the total energy expenditure over a 24 hour period (2) and thus leads to a change in body composition.
Recommendations
There are no detrimental effects to participating in exercise in a fasted state. It really comes down to personal preference. If you prefer exercising on an empty stomach, go for it. If you prefer exercising after eating, then do that. If you are only going for a walk on an empty stomach in the morning because you have been lead to believe that this will assist in fat loss, but you actually find it super uncomfortable, then I am here to tell you it is not necessary. However, if you enjoy going for a walk or exercising before eating and find exercising on a full stomach uncomfortable, then keep exercising in a fasted state. The main take away from this is: keep doing whatever works for you, neither fasted or fed prior to exercise is superior based on the available research.
References
(1) Escalante, G., & Barakat, C. (2020). Fasted Versus Nonfasted Aerobic Exercise on Body Composition: Considerations for Physique Athletes. Strength & Conditioning Journal, 42(5), 71-78. Chicago
(2) Hackett, D., & Hagstrom, A. D. (2017). Effect of overnight fasted exercise on weight loss and body composition: A systematic review and meta-analysis. Journal of Functional Morphology and Kinesiology, 2(4), 43. Chicago
(3) Vieira, A. F., Costa, R. R., Macedo, R. C. O., Coconcelli, L., & Kruel, L. F. M. (2016). Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-analysis. British Journal of Nutrition, 116(7), 1153-1164.