I usually eat between 1500-1800 calories a day. If I eat 1800-1900 a day, I have to do like 70-80 mins of exercise a day to meet my calorie deficit and that much exercise in one day just sucks. My guess is that if you eat 2000 calories a day you'll have to do a freakin lot of exercise to keep up with eating that much. It can be done but it would be hard for me and it might be hard for you too.
According to my Body Media armband I need a calorie deficit of 1,000 calories per day to burn 2 pounds off per week. So I usually eat 1600-1700 and do 30-40 mins of exercise a day to get that daily deficit.
My Body Media armband (http://www.bodymedia.com/) costs $150 but you can get the basic model for $100 and you get three months subscription for free. After that it's $6 a month and you can pay for a year or two at a time so you don't have to worry about it.
The Body Media armband device is something you wear 24/7 even to bed and it counts the calories you burn. You can sync it with your Spark People account and so when you log food on Spark People it transmits it to the Body Media armband to tell you your calorie deficit (calories burned vs calories eaten). IT TAKES THE GUESSWORK OUT OF LOSING WEIGHT. You'll be able to see if you ate too much and need to exercise more and even for how long or you'll be able to see if you can afford to have a little extra treat in your day if you worked hard enough.