I've found that you can do a fair amount of weight loss by making eating trivially inconvenient. This allows procrastination to work for you and helps discourage eating when you're not all that hungry.
Examples:
Record everything you eat and how much of it you eat, unless it is something very healthy like raw fruits/vegetables or a calorie free item. This helps turn healthy foods into a lazy option.
Take a small serving of food rather than taking one big portion, and then put the container back, which makes not having a second helping into a lazy option.
As a more meta example, allow yourself to have a demotivated day periodically while not changing the overall habit of you being dieting. If you've eaten healthy for the past 3 weeks, and you cheat tomorrow, but then you go back and eat healthy for another 3 weeks, and then cheat again, the amount you're eating healthy as a percentage is frankly still great enough that your health will be much better for it. You want thinking of yourself as "not dieting" to take a concerted effort on your part to break the habit, so that you can instead be lazy and continue to keep your habitual dieting, as opposed to thinking of dieting as a broken habit from only a brief lapse.
(Note: I was able to get this kind of thinking to work for weight loss, so I'm a lot thinner now, about a hundred pounds below my high weight and now at a healthy BMI range, but I'm still not that athletic or physically fit, so if being a good hiker is very important to you, this may not be sufficient even if it works for you just like it worked for me.)
"Cryonics has a 95% chance of failure, by my estimation; it would be downright /embarrassing/ to die on the day before real immortality is discovered. Thus, I want to improve my general health and longevity."
That thought has gotten me through three weeks of gradually increasing exercise and diet improvement (I'm eating an apple right now) - but my enthusiasm is starting to flag. So I'm looking for new thoughts that will help me keep going, and keep improving. A few possibilities that I've thought of:
Pride: "If I'm so smart, then I should be able to do /better/ than those other people who don't even know about Bayesian updates, let alone the existence of akrasia..."
Sloth: "If I stop now, it's going to be /so much/ harder and more painful to start up again, instead of just keeping on keeping on..."
Desire: "I already like hiking and camping - if I keep this up, I'll be able to carry enough weight to finally take that long trip I've occasionally considered..."
Curiosity: "I'm as geeky a nerd as you can find. I wonder how far I can hack my own body?"
Pride again: "I already keep a hiker's first-aid kit in my pocket, and make other preparations for events that happen rarely. How stupid do I have to be not to put at least that much effort into making my everyday life easier?"
Does anyone have any experience in such self-motivation? Does this set of mental tricks seem like a sufficiently viable approach? Are there any other approaches that seem worth a shot?