Besides look in the mirror?<p>But seriously, in my case, I'm determined to never become an insulin-dependent diabetic. I was over 340 lbs. 16 years ago (and believe it or not, I was <i>not</i> a big eater compared to male peers), then I read about low-carbohydrate eating strategies, and had slow but significant success (lost over 120 lbs in a 20-month span).<p>But getting back to the question: my motivators were/are:
1) appearance
2) staving off degenerative disease (diabetes, heart disease, etc.)
3) activity enjoyment (e.g. hiking, volleyball, etc... weight is a limiting factor and contributes to injury)<p>My biggest problem is maintaining a regimen when I am <i>not</i> getting results. This is how I derailed in the first place in my late 20s -- despite running 4-6 miles 2-3 times a week, I couldn't lose an ounce.<p>Also, keep up on current science: for example, you could expend a lot of effort doing something that isn't that helpful if you a part of the population that is a low genetic responder to cardio (see the University of Bath study as covered in Michael Mosley's "The Truth About Exercise" on PBS). In my case, I also exhibit the classic symptoms of AD-36 exposure, so I have a tougher row to hoe.
The thing is that once you get your diet and exercise routine right 'for you' then the issue of how to keep it up goes away. It's so self-reinforcing that you would be hard pressed NOT to eat and exercise well.<p>The hard part is getting it right for you. I like to run and I've run my whole life so exercise was never an issue, guess I lucked out there. I've tried going to a gym many times and it just is not for me, for example.<p>Whereas it took until my 50s to figure out that a low-carb diet was right for me. Before I had a terrible sweet tooth, but now you couldn't pay me to eat sugar.<p>So my advice is to try lots of things without getting hung up on the dogma associated with each, until you find the things that click.
By understanding that change does not happen immediately. I read somewhere that it takes 60 days to form a habit. Rather than look for changes, I looked to form a habit of walking every day for an hour. I've lost 25 lbs in the past three months. I didn't see the slightest bit of a difference in the first two weeks, but I kept going. Make it a habit and you won't need to motivate yourself.
Its not about being motivated, its about designing your lifestyle, if you want to eat outside but the table is inside, move the table outside. Design your life so that you have to workout, rather than fighting temptation just don't have crap in your cupboard. Sell your car and buy a bike.
Exercise: make it part of your commute, by biking or walking to work. Or something you enjoy, like hiking, cycling, basketball, tennis, etc.<p>Eating healthy: remove everything you shouldn't eat from your home and only eat food out of your home. Eat Soylent for one meal a day.
I think it is not too hard. For myself I am just feeling a lot better when I eat healthy and go to the gym. I am more productive and more alive. I can learn more, work more and so on.
I had peripheral neuropathy (tingling in my hands and feet). It turned out to be a vitamin B deficiency. But while we were trying to figure out what was causing it, one of the options was that it was an early onset warning for diabetes. I asked the doctor what to do now so that I didn't get diabetes in five years, and he said, "lose X pounds". That set a target weight for me, and gave me a pretty strong incentive to try to hit it.<p>In actual fact, I tend to run about 2-3 pounds above my target, but I take stronger action above that.