Yep. Carbs cause a larger release of leptin than either fat or protein.

Of course, at some point the leptin system breaks down, probably due to desensitized receptors. But in a negative calorie state, you can take advantage of your leptin sensitivity.

UD 2.0 by Lyle McDonald is a good basic program that is built off the premise of carb cycling (and the effects on leptin and insulin).