One of the essential questions I ask myself about eating/living healthily is if i really love what I'm eating. If you really love what you're eating, then it's one hurdle overcome. It may or may not be the right hurdle to overcome but at least you can reevaluate yourself. For example, somebody who loves eating greasy food everyday or often is obviously not loving the right thing. On the other hand, one may not love vegetables or fruits but it doesn't make eating them unhealthy.
I believe that if anybody can guide me in my endeavours on healthy eating, I must answer the question posed above. If it's the honest answer but not the best one, then I know there's something I need to do about what and how I eat. You may know all the healthy foods, what to eat and what not to eat but until you start looking retrospectively at your eating habit, you may not know you're doing the unhealthy thing. I think my body is mine to look after. Now if I can't trust myself to look after my own body well, then how can I trust myself to look after anything.