Intermittent fasting is one of the most popular types of diet at the moment because it is an effective nutritional strategy in terms of weight loss. The main objective of this review is to analyze the effects that intermittent fasting has on sports performance. We are going to focus on analyzing physical capacities: aerobic capacity, anaerobic capacity, strength and power, we are also going to analyze its effect on body composition. For this, a bibliographic search was carried out in several databases where 25 research articles were analyzed to clarify these objectives. This review was registered in PROSPERO with code ref. 407024, and an evaluation of the quality or risk of bias was performed. After this analysis, results were obtained regarding the improvement of body composition and the maintenance of muscle mass. Finally, it can be concluded that fasting provides benefits in terms of body composition without reducing physical performance, maintenance of lean mass and improvements in maximum power. But despite this, it is necessary to carry out new studies focusing on the sports field since the samples have been very varied.