Adherence is always the hardest aspect of reaching a physique goal. The physiology is very simple, if you eat less and move more, your body drops weight & fat, this is thermodynamics, on the flip side, if you eat more and move less you gain weight. Energy cannot be created nor destroyed, just transformed or transferred from one type to another - remember this in school?
Well it's yet to be disproved, so when you eat , that energy is stored as fat, unless we use it as fuel... This is very simple, however putting into practice is much harder, otherwise we would all have the look we want.
Adherence takes practice, everything we do takes practice. There will be lots of mistakes on the way to changing your lifestyle habits to the extent that adherence then isn't a choice but habitual behavior.
So don't be disheartened when you can't Adhere, this then doesn't mean oh well I can't do this so I may as well go back to eating crap all day. It means you just need to keep practicing, each day remind yourself of the goal and try your best to tick off that day as close to 100 percent as you can, some days will be great, some not so much, but if across a week your average more great days then not, your making progress I assure you.
Thanks to JP