Yup actually we all develop patterns and addictions over the years and I don't think any of us are saying it is easy to change a pattern. But it can of course be done. Studies have shown that if you do something for 3 weeks, your body / brain begins to accept that as a new pattern for you. So short-term goals are critical in any life change.
What I've really found with people that I've talked with is that it tends to get "progressively better" which helps you stay on track. You begin, because of your high-bad-carb diet, lethargic and unwilling to exercise. As you eat healthy carbs, you get more energy and start to lose weight. As you lose weight, you get less tired just walking around. Now that it's easier to walk around, you actually go for walks, which then keeps your metabolism revved, which helps you lose more weight, etc.
My boyfriend began at about 310 pounds and simply did not want to walk or move or anything. When we switched to the low carb diet he got down to 230 or so in about 6 months. It wasn't that he starved himself - far from it. It wasn't that he did anything extreme either. He cut out the fast food and sugary soda. He switched to salads, grilled fish, omelets, etc. So he was still eating ample food and vitamins, and drinking a ton of water. But once that weight started to come off, he was more interested in walking. Soon he was playing basketball (albeit slowly) on his work team. Soon he was doing really well in basketball, and joined a baseball team. So now his metabolism stays in high gear pretty much all the time, which means his body is actively burning fat / calories far more than it ever did.
BTW on the candy issue, there are REALLY tasty sugar-free candies out there. So if you really find a craving for candy, just make sure that only sugar-free types are in your house. That way even when you give in to a craving, it really doesn't hurt.