I’m currently in (deliberate) maintenance but it’s the same situation except that it’s worse in the sense that it’s a permanent plateau with no further favorable change to be anticipated on the horizon. What enabled me to walk the walk and keeps me on track at present isn’t motivation or willpower – these helped me overcome early inertia and adversity but have long been depleted; it was merely a successful redefinition and internalization of normalcy, which one could call “acquired discipline” I guess. I have acknowledged that in order to reach and sustain this current state I’m in there’s a very specific set of constraints that I had and will still have to meet going forward, day, week and month in and out for the foreseeable future. For instance over lunch with extended family today I was offered ice cream, which I proceeded to decline as I’m close to exceeding my margin of “exceptional exceptions” and “social compromises” for September. It’s an objective constraint but subjectively doesn’t feel like one, as over the past 15 months dessert hardly ever would be seen on my table when having lunch by myself, thus when presented with consumption opportunity as was the case today it naturally feels abnormal and trivial to avoid, not the other way around.
So my recommendation would be to (further) redefine what “normal” ought to mean to you, such that you’re empowered to reach and maintain your goals with the least perceived effort, or to set yourself up for success if you will. Obviously while you’re at it you should also try to factor in others’ “normals” and, should conflict seem likely, maybe evaluate alternatives including targeting a less ambitious goal if need be (e.g. I would consider it unreasonable for someone surrounded by morbidly obese individuals at home and work to pursue say a BMI of 20 and 10% body fat; it would be an experiment just bound to fail sooner or later, assuming the environment wouldn’t change).