However, I can't seem to be able to make a connection with the examples your parent comment mentioned. For example, if you want to lose weight but keep eating fast food despite that---what is the healthy need manifesting through that, and how do you address it in some other, good way? Same with being addicted to e.g. alcohol or smoking.
That really depends on the individual; if you'd like to sit on my couch for a couple years ... (I'd have no idea what to do).
But as examples, if your body doesn't need something nutritionally (e.g., more energy), perhaps the junk food is a source of comfort and relief from stress (i.e., 'comfort food'); there are healthier ways to obtain relief from and to otherwise deal with stress. Perhaps the buzz from the sugar and fat is an escape or makes the person feel energized; again, there are healthier solutions.
Again, I don't pretend to be an expert and what I wrote in the GP isn't the answer to life, the universe, and everything. Part of nurturing yourself is pushing yourself at times and training, but IMHO without battling and abusing yourself - again, like a good coach, teacher or manager.
> Same with being addicted to e.g. alcohol or smoking
I would think that physical (i.e., chemical) addictions are different; your body requires that chemical. Alcoholism is a disease, AFAIK.
I'd argue that this is not completely true, as in, there's a significant psychological component as well. I can give a personal example. I'm trying to quit smoking by gradually lowering my nicotine intake, or "cut down to quit". Currently, I've reduced the amount I smoke by several orders of magnitude, and I no longer feel any kind of physical need. Still, I procrastinate with actually making the leap to non-smoker, and I find that my desire to smoke is now driven by purely psychological impulses that I have a lot more trouble controlling than merely ignoring physical withdrawal symptoms.
I'm trying to come up with a good explanation of all that, and you offered a compelling view on the subject―that's the only reason I'm so curious in debating this topic.
Personally, I figured out that I was going to engage in some kind of habitual 'escape' periodically (I would guess that is true of everyone). It didn't matter what it was; if I stopped one, then I'd start another. As a result, I try to purposely choose things that are as healthy as possible, or at least harmless, and maybe even a little productive. Hobbies can be good for that, though they aren't exactly the same thing.
EDIT: Some clarifying edits
The interesting thing is I believe I can make a convincing argument that "life" is a disease that can be overcome - for example, a highly trained monk can meditate himself to death, ignoring the body's desire for food or water. When it comes to us, "require" can, with training, be nullified. We can even, apparently, out-think our most basic pain responses (see: the burning monk).
If it's not a nutritional deficiency, then perhaps it's a snacking habit, so maybe switch to nuts, sunflower seeds or fruit. The habit starts losing its power when you're no longer flooding yourself with high doses of sugar and/or salt, which is where the habit's positive reinforcement comes from.
Perhaps "control" and "battle" are the wrong model. Some broad, general suggestions based on what experts have said:
Respect yourself: If you are doing something over and over again despite not wanting to, there probably is a good reason for it, a legitimate healthy need, even if the expression of that need is unhealthy. Respect that need and its priority as legitimate and serious. Find a healthy, productive way to address it. It should be no surprise that the response is unhealthy: Imagine if someone else had a real need and your response was to ignore it and abuse them constantly for acting on it; how would that person behave?
Know yourself: Know your strengths and limits; don't put yourself in position to fail and then abuse yourself for failing. Again, imagine you were someone else's manager, you knew their limitations, and yet you kept putting them in position to fail and then abused them over the results. That would be a horrible failure of management, not of the employee.
Have compassion for yourself. Like every human ever to live, you also will live your whole life with serious flaws.
Nurture yourself: Work together (so to speak) for change. That's how real change happens; that's how good parents, good teachers and mentors, and good managers accomplish things. Fighting with people just entrenches the problem.
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That feels a little too ... bullsh*tty to post - loose, imprecise ideas with little serious foundation included; my apologies. But I'm not sure how to tighten it up, don't have links at my fingertips, and posting it seems better than not.