Can drinking more make you eat less?

Yes.

Via Brain Trust: 93 Top Scientists Reveal Lab-Tested Secrets to Surfing, Dating, Dieting, Gambling, Growing Man-Eating Plants, and More!:

Dr. Davy showed this by prescribing two cups of water before a meal. In the course of a twelve-week study, subjects who drank water before a low-calorie meal lost an average of five pounds more than subjects who simply ate the low-calorie meal.

In a yearlong follow-up to this study, Davy found that even with the removal of the low-calorie diet, people who drank water before meals were able to keep the weight off while people who went back to their lives as usual tended to gain some, most, or all of the weight back.