Okay so to be healthy, I need to eat right before I roll...
Yes, you do need to have adequate resources in the form of carbohydrates and vitamins in your body prior to a roll. Regretably, it's a little trickier than that, because food in your digestive system can interfere with your body's absorbtion of the MDMA, resulting in a prolonged come-up. Since the come-up is typically the least enjoyable part of the experience, you want to make sure that you eat a good meal no later than 4 hours prior to consuming your pill.
Dang! Why is this so complicated?
It's not as tricky as you might think. For example, if you are planning to take MDMA at 9pm in the evening, eat a good breakfast when you get up and then a high-carb lunch/dinner no later than about 4pm and you will be just fine.
I meant to eat, but it was a busy day...should I just skip it then?
The best thing to do in this situation is get some liquid meal replacements such as Naked Juice, Ensure, or even just heavy fruit juice such as Kern's Nectar. This will give your body at least some of the resources it needs without requiring digestion of solid food. As an added bonus, most of these are rich in vitamins.