From a lot of my own experience;
5-6 small meals a day, 5 including a whole grain carb and lean protein, and at least two of those including veggies or greens, the last being your snack, whether fruit or air popped popcorn. Total calories per day shouldn't exceed 1500. The way I learned to eat was with Six Week Body Makeover by Michael Thurman. I lost six pounds the first week and only actually did the eating schedule for four of those days. The other three days I ate a ton, I'm so weak willed! I got dizzy for the first two days while my blood glucose levels were evening out, but I would drink a little juice or eat some wheat thins when this happened. It stopped after a couple of days.
Cut out all refined carbs and pop, and diet pop too. Cut out and use of artificial sweeteners, they're very bad for you. Try stevia, honey (not too much) or sweet n low for sweeteners if you must sweeten.
Exercise, and use weights. Every pound of muscle you have burns twice the amount of calories as every pound of fat. You gain a pound of muscle, you burn 150-300 more calories a day doing nothing.
If you do this, your metabolism will crank up to full speed and you'll lose weight while eating every 2 1/2 hours, and your glucose levels will even out. If, like me, you give up for some reason, you'll end up like me, insulin resistant and on Metformin to fix it. I've lost 40 pounds since the Metformin, but the doctor says now that I may never be able to get off of it if I don't start eating the way I know I should, and it will lead to diabetes (which does not run in my family). And I still have another 40 to lose.
Don't make the same mistake I did.