15 pounds in a month is nearly impossible without cutting out food completely. 1-2 pounds a week is the most realistic goal to have.
I lost 10 pounds a month for 6 months without breaking a sweat, except at the gym, and continued drinking to boot. I have had a stable weight now for close to 3 years, at 165 pounds. Just dump the potatoes, pasta, bread, and rice while doing it, and otherwise eat what you want. But have a protein drink every morning for breakfast. I kept telling Bushie that, but he put me on ignore. He just doesn't give a damn. Deep down inside, he wants to be fat to avoid life. JMO.