I think it is much better to eat one big meal that will fill you up in the middle of the day. Make it a healthy low calorie vegetarian one. Most likely, you will consume far fewer calories this way and it will make you full and content. But regardless of what else you do, the key to losing weight is lowering your caloric intake until you start losing weight at a rate you are comfortable with. The number and size of meals is irrelevant. Just focus on calories.