How Can I Find Motivation?

Hello, FB community! I've had a problem almost every time I've tried to lose weight, and that's eating healthy food. I know the benefits of it and how it can hugely help me not only with fitness but preventing illnesses, but I feel like I can never motivate myself to eat real food for more than a week or so. And the sad part is that during times where I've been eating real food for a while, junk food becomes incredibly unappealing to me, and yet I still end up returning to it. What are some tips to get over this block? Thanks!