Although exercising in a fasted state increases fat utilization during the session, total fat loss over 24 hours is identical to that of training after eating, provided that daily caloric intake is equivalent.

noli's read

This advice is based on a solid scientific foundation and perfectly reflects the research consensus. A meta-analysis by Vieira et al. (2016) confirms that exercising in a fasted state temporarily increases fat oxidation during exercise. Nevertheless, another meta-analysis conducted by Hackett and Hagstrom (2017) demonstrates that this effect does not lead to any difference in long-term fat mass loss. These conclusions are notably supported by a randomized controlled trial (RCT) by Schoenfeld, Aragon, and colleagues (2014). In that study, the researchers observed identical body composition changes in dieting women, whether they trained in a fasted state or after a meal. Indeed, the body compensates for this increased fat utilization during exercise by burning more carbohydrates for the rest of the day. The choice of whether or not to train in a fasted state should therefore primarily depend on personal comfort and enjoyment during exercise.

the sources

1. 1Hackett D, Hagstrom AD 2017
2. 2Vieira AF, Costa RR, Macedo RCO, Coconcelli L, Kruel LFM 2016