I think the reason why type 1's find it so hard to lose weight is because when there is a lot of insulin active in your body, it blocks all the things that break down fat and helps to store fat. I'm not positive but, I think when a non diabetic eats and insulin is released from their pancreas, it takes a shorter amount of time to be cleared from their systems.
In between meals is important for weight loss because this is when the body breaks down it's stores and uses them for energy, but since a lot of the GM insulin's we use take 5 hours to get out of our system, like novarapid, there doesn't seem to be a break where there is only a small amount of insulin and the body can break down stored fat, so we lose weight.
The way I found around this is to stop taking bolus insulin. Using only basal insulin, there isn't enough insulin to stop the body from breaking down it's stores and I've found I can lose weight very quickly doing this. Since I'm not taking bolus, I have to eat a ketogenic diet which is 65% fat, 35% protein, 5% carbs. The body adapts to using fat as energy instead of glucose, by using free fatty acids and ketones as energy.
Keeping your sugar levels stable while doing this is even more important, because you'll be producing a lot of ketones for energy, but if your sugar levels are high this can lead to ketoacidosis. One thing to remember is ketones are only bad when your sugar level is high (above 7.6mmol/l) and are just a sign that your body is disposing unused energy when your sugar levels are fine.
It seems the less basal I take, the faster I lose weight, but you need to find a balance of how little you can take while keeping perfect sugar levels. The low carb diet will make you more sensitive to insulin and I also have to exercise everyday to stay sensitive enough to keep my basal injections low. I've lost 40lbs doing this I've read that Doug Burns does something similar when he lost weight to compete in Mr Universe. He is type 1 and exercises after eating carbs so he doesn't have to inject insulin, the exercise and basal insulin lowers his sugar levels after eating. You'd be surprised how little insulin you can use when you eat tiny amounts of carbs and exercise a lot.