This quote comes to mind:
"If we would just recognize that life was hard, things would be much easier".
Those breezier times do make this *simpler*, that's for sure! But that absolutely can not and will not always be the case.
But it's not just adhering to a healthy lifestyle that's got harder and easier times. It's like that with lots of very important things.
To name a few:
Work, sometimes it's gratifying and relatively easy - other times not so much.
My marriage, sometimes its effortless, other times, oy.
Raising my children, sometimes it's an utter joy, sometimes it's heart wrenching and downright frustrating.
Friendships, sometimes they are a delight and add to the quality of my life, other times, quite stressful and even unpleasant.
That's why a steadfast, ironclad commitment is needed for all things that are vital and important. Throwing in the towel with things that matter are not an option!