Well first that is a lot of weight to lose in less than a month. Special reason you want to lose that specific amount. Some tips:

Track your intake, if you want o lose that much weight you are going to have to be very focused and really know what you are putting in your body. In order to lose 1 lb of fat you have to eat 3500 calories less for every pound. You need to figure out what your body currently needs just to maintain your current weight and than work back wards. You should not eat less than 1200 calories per day and for the best weight loss you will need to exercise at least 45 minutes 6 days a week. If you can do strengthen exercise you will build muscle and burn fat faster than just doing cardio. You need to drink your water at least 6-8 glasses per day, limit salt intake and only eat lean meets and vegetables. Going to venture out here and say yes it carbs but be wise in your choices and cut them way back after the noon meal.

I hate to tell you but there is no magic way to do this with out a lot of hard work. Is it it doable yes but is it worth going on a diet instead of gradually losing weight?

^^^^^^^^EVERYTHING LovetheNewMe said!!!

Plus....I had a plateau for about 4 months when I was working 70 hours a week & didn't have time to exercise. That was the only thing that I had changed; still was watching what I ate, but no exercise. After work slowed down, I got back into the gym & started losing again. You HAVE TO MOVE, you have to work out, walk, any exercise to burn those calories & strengthen your body!! AND water water water!!!

15 pounds is definitely do-able....20 might be pushing it though! Do it healthy so it stays off and you can continue on your journey! Good luck!!!

I agree with everything Love and Gym_addict say. Plus, I think your goal may be a little lofty but I think if you track and get moving, it will happen.

The only other thing I would add is I know when I am not drinking enough liquids and taking in enough protein my weight seems to stall. As soon as I increase both, it picks back up again.

Best wishes to you.