T3 helps to increase the calorie deficit. T3 doesn't specifically target fat. It targets fat and muscle by using more calories. If you were to eat enough food to maintain, it would basically cancel out the effect. Using steroids will help you to hold on to muscle while using T3 but if your dose of T3 is high enough, you can still lose muscle. The key is to keep the dose of T3 low. The better your diet is, the less you will need to make a good impact. The lower you can keep the dose, the less likely you will be to go flat or lose strength