If you want to reward yourself after a workout, do it with another helping of protein or some carbs. Just be sure to skip the fast immediately after the gym. Brand-new research from Medicine & Science in Sports & Exercise shows that high-fat feeding after workouts suppress muscle gain.
In the study, trained athletes performed two workouts a day: high-intensity interval training in the morning and steady-state cardio in the afternoon. In one period the athletes were given a high-carb diet, and in another period they consumed a high-fat low-carb diet. During the high-fat phase, a process known as ribosomal protein S6 kinase 1 activity was reduced post-exercise.
This caused researchers to comment “…post-exercise high-fat feeding may impair the regulation of muscle protein synthesis and post-exercise muscle remodelling, thereby potentially causing maladaptive responses for training adaptation if performed long-term.” Muscle glycogen was also lower during the high-fat diet, which is not a favorable state for long or intense workouts.