To drop weight you have to eat less calories than you burn. Extra exercise helps the math equation...
But the biggest thing is controlling what we eat. It's also the hardest and it's ongoing. You can't work hard to get to where you want to be and then get there and go back to the old ways. It's a nonstop decision making process. It's all about making good choices MOST of the time. I say Most because we all deserve to splurge and enjoy the deliciousness in life.