There could be several reasons why you're gaining weight from Orangetheory workouts. One possibility is that you may be consuming more calories than you are burning, which can lead to weight gain. Another possibility is that you may be gaining muscle mass, which is denser than fat and can lead to a temporary increase in weight. Finally, hormonal changes, medication, or medical conditions could also contribute to weight gain. It's important to consult with a healthcare professional to identify the underlying cause.