Martin/paula is right, if you have a larger breakfast u are less likely to get hungry throughout the day, plus u burn it off during the day.
Just eating fruit all day long isn't exactly a balanced diet. If you want to lose weight then you can still eat all of the right foods but in moderation, cut out all the unhealthy fats from ur diet, ur body still needs some fat, but ensure its the healthy types ie omega 3 fats found in fish, olive oil etc. Balance ur carbs, protein, veg, fruit, calcium and healthy fats out throughout the day to give u all the nutrients u need. Lets face it if u have the discipline to stick to fruit all day (yuck!), u'll be able to stick to a healthy eating plan no probs!