1500 calories?! For a guy your size, that'll be as filling as a mocha latte and a couple fly farts. Just a couple of things to think about:

1) get your Basal Metabolic Rate measured. There are online calculators, but they are as stupidly inaccurate as BMI. Talk to your doc or a dietician to get a snapshot, or shell out some dough for a device to carry around with you. You NEED to know how many calories your body needs just to maintain itself. I got mine done twice over the past 18 months, and (averaged) I found that I need 2300 calories to run all my systems. (The online calculators were about 600 calories off!) 2300--And I'm a helluva lot smaller than you. I'm afraid if you limit yourself to 1500, not only will your body balk and produce some hideous cravings, but it will also begin to cannibalize itself. That will cost you all the muscle and strength you've gained in the past year.

2) Spend the next 7-10 days logging what you eat currently (non-program). That'll give you a clearer idea of how much to cut back--find that sweet spot down nearer your BMR. The weight loss won't be dramatic or fast, but it will preserve your gains. Be careful you don't downshift your metabolism into starvation mode. Unless you plan on eating 1500 for the rest of your life >shudder<.

I'm not a dietician, not a health professional. If you have better, more credible advice, take it. You know your body, I'd just like to see this stage work well for you! Giddyup.