Are you embarking on a fasting journey and worried about muscle loss? You are not alone. This concern is prevalent, especially among those who are new to the practice of intermittent fasting, a popular weight-loss strategy where you cycle between periods of eating and fasting.
Intermittent fasting, or time-restricted eating, typically involves fasting for 16-24 hour windows several times per week. One area of concern is whether intermittent fasting leads to a significant loss of lean body mass or muscle tissue. It’s worth noting that healthy weight loss involves losing fat while preserving as much muscle as possible. Therefore, if intermittent fasting leads to muscle loss comparable to chronic caloric restriction, it would undermine its utility as a weight loss tool.
The science behind intermittent fasting is still evolving, but the data we have so far suggests that those who lose weight through chronic caloric restriction lose approximately a quarter to a third of the weight as lean tissue. However, if practiced correctly, intermittent fasting is unlikely to cause significant muscle loss. Some data even shows a loss of muscle mass with intermittent fasting, but consuming a moderate to high amount of protein seems likely to mitigate or completely prevent this loss.
Adding resistance training to a protein-rich diet also makes muscle loss very unlikely. However, there are insufficient data to draw conclusions about the risk of muscle loss as the frequency of intermittent fasting increases, especially when fasting for less than 24 hours “too often” over extended periods.
Intermittent fasting is more than just a way to cut calories; it’s a lifestyle change that can switch your metabolism from sugar-burning to fat-burning mode. When we break a fast, we don’t necessarily “make up” for the calories we missed while fasting; this leads to built-in calorie restriction. Also, fasting—especially in the context of a low-carb diet—depletes the liver’s glycogen stores usually within the first 24 hours, leading to the mobilization of fatty acids from fat stores for use as energy.
It’s important to note that the literature on this topic often includes studies of fasting that lasts for weeks, which can shift the focus away from the effects of short-term fasting. If you’re only fasting for up to 24 hours at a time, you should care more about what’s happening in the hours leading up to a fast and the fasting period itself, not what’s happening over the course of several weeks without food. Because of the lack of detailed scientific evidence specific to the first 24 hours of a fast, we are left to extrapolate from less specific literature.
Finally, remember that every individual’s experience with fasting will be unique. Always listen to your body and consider consulting with a healthcare provider before starting any new dietary regimen. If you’re worried about muscle loss during your fast, know this: even with lower body fat, any lost muscle bounces back swiftly post-fast, thanks to the ‘retraining effect’, especially if you’re exercising. Keep going strong!