If you are committed, you will shape your environment, so you don’t need a lot of willpower. As the day progresses, our willpower diminishes and leaves us vulnerable to temptation. It is a lot easier to shape our environment then to try and exert control over it.
If you blew your diet last night eating junk food, I would argue that your problem isn’t a lack of willpower, it is a lack of commitment. Why was that junk food in your house in the first place? It isn’t good for you, and it isn’t good for anyone else under your roof. You don’t want to deprive your children? Of what? A lifetime of sugar addiction? A lifetime of struggling to control their weight and eating. Anytime you decide to change, you can. But it requires commitment. Shape your environment to foster good habits and remove the temptations that cause you to fall into bad habits.
Learn more, about Willpower.