There are a few things you can do to maximize your success and minimize fat gain on a reverse diet:
Lift heavy weights. This will allow you to put your extra calories to good use, powering workouts and increasing muscle mass, which will in turn help to increase your metabolic rate and limit fat gain.
Don’t use cardio as a calorie-burning tool. The whole point of a reverse diet is to gradually increase the amount of food you eat to keep you in a calorie surplus. This surplus will trigger an increase in your metabolism. If you’re increasing cardio every week to try and control your body weight, you’ll erase the calorie surplus we’re trying to create through reverse dieting, rendering the reverse diet ineffective.
Choose a less aggressive reverse diet setting. By increasing calories at a very slow rate, you’ll minimize fat gain while also giving your metabolism more time to adapt.
Spend a substantial amount of time on maintenance after your reverse. The longer you can stay on higher calories, the greater the odds that your body will completely adapt to these and easily drop weight when you finally switch your goal to fat loss.