Losing muscle while fasting is a common concern, especially among those who are new to fasting. However, there is no need to worry. Fasting does not cause muscle loss. In fact, research has shown that intermittent fasting may actually be more effective formaintaining muscle massduring weight loss than non-fasting diets. According to a 2011 study, intermittent fasting causesless muscle lossthan regular calorie restriction diets.