Have you ever played the game, would you rather? It's a fun game. Having to choose everyday what you should eat or choosing to go to the gym, is exactly like playing "would you rather."
Willpower is a constant battle between the WILL of your logic and the POWER of your emotions. Willpower is a choice. But just as willpower is a choice, so is choosing what you eat or making the decision to work out.
Snacking on junk food is a choice, you could snack on fruits and veggies and be just as satisfied. But just because you choose one doesn't make you incapable of the other. It's about being aware of your choices and why you make them and also about having options to create better habits. If you're limiting your options to eat better then you're choosing to do that, it's not that you don't have willpower. So set yourself up for success. Willpower is about the actions we take to create better habits. If you know that you lack restraint going to family BBQ's, set yourself up for success. Make a plan before you go and stick to it. If you want to have dessert at the BBQ and forgo drinking alcohol, stick to that plan. Having a plan helps with those chronic issues that temp us.
And one of the worst choices I see people make, don't permit yourself to be "bad" because you've been doing so good. This phase means you don't reward yourself for doing good. Just because you worked out this morning does not mean you should have a tub of ice cream later. Or just because you ate well all week does not mean you should treat the weekend like a free for all buffet. This self sabotaging behavior only makes you feel guilty and does not contribute to your goal of making better choices or habits. Eat food you enjoy in moderation so you're not making it harder to make better choices. And reward yourself for doing well. Just try not to make it food related everytime.
Learning and understanding why you're doing the things you're doing and seeing success in the tiny steps you make to creating a healthier lifestyle is a decision that you'll never regret making. Choose you! And remember willpower gets you started. Habits get you results.