I posted something on the open thread about exactly this:

The part of my brain that loses to akrasia seems incredibly stupid, whereas my long-term planning modules are relatively smart. I've been trying to take advantage of this by a campaign of active /warfare/ against the akrasia-prone part of me. For instance, I have deleted all the utilities on my laptop needed for networking. I can no longer browse the internet without borrowing someone else's computer, as I am doing now. I also can't get those networking utilities back because for that I need internet. I also destroyed both Ubuntu live-CDs I had, because I can get to the internet through those. Thus far, my willpower has thrice failed me, and each time I have tried to get internet back, and each time I have failed. I count this as a win. The principle is more general, of course: only buy healthy food, literally throw away your television, delete all your computer games, etc.. The first few days without some usual sort of distraction are always painful; I feel depressed and bored of life. But that soon clears up, and my expected-pleasurable-distraction setpoint seems to lower. This is like a way of converting fleeting motivation into long-term motivation.

If you don't think this will give you said "immediate gratification", try narrowing your definition of "current". Are you viscerally compelled to buy a pack of cookies? No, you're just viscerally compelled to eat them. People seem to extrapolate that visceral compulsion so they feel viscerally compelled to buy the pack of cookies, and you don't have to extrapolate like that.

I've also been experimenting a lot the past year with deliberate self-delusion as a way of increasing willpower and it seems to be working. I know some here have argued that deliberate self-delusion is a bad idea, but I'm entirely unconvinced. Rationality is what wins.