It "should" be so easy. Do what works. Stop doing what obviously doesn't work. Or what hurts.
Losing weight (or getting healthy) might be like any long-term, worth-while project. Like saving money, or walking from coast to coast. It should be linear - predictable. With a few stops here and there to take in some points of interest. Or a change of plans now and again. Or to compensate for bad weather, flat tires, or just being tired.
And for the times that you make bad choices, simply do this - choose again.
Every minute is a chance to start over.
And learn through correction, not punishment.
There's no place for guilt and shame when you are a dedicated learner. Students are expected to make mistakes. Babies learn to walk by falling down a lot, and getting right back up. With a little help, encouragement and positive reinforcement. "You CAN do it!"
It seems hard to do because it is hard to do! It is not easy. If you think it's hard today, wait 'till you see tomorrow! Now is the time. It will never be easier than right now.
"I set this goal for myself. And for what ever reason. Why would I let anything in this world of time and space stop me? Or delay me? Or talk me out of it completely?"
Some say the real "lesson to be learned" is in the mind. And the body merely follows.
Perhaps it is all about Love. All you need is Love! Love, and let yourself be loved.