Dilbert creator Scott Adams thinks systems are better than goals. In fact, he thinks that goals are for losers:
To put it bluntly, goals are for losers. That’s literally true most of the time. For example, if your goal is to lose 10 pounds, you will spend every moment until you reach the goal—if you reach it at all—feeling as if you were short of your goal. In other words, goal-oriented people exist in a state of nearly continuous failure that they hope will be temporary.
If you achieve your goal, you celebrate and feel terrific, but only until you realize that you just lost the thing that gave you purpose and direction. Your options are to feel empty and useless, perhaps enjoying the spoils of your success until they bore you, or to set new goals and re-enter the cycle of permanent presuccess failure.
Foodist author Darya Rose agrees, and credits her success (in health and weight loss) to setting up a system she calls her healthstyle.
Semantics? Or meaningful difference? I must admit I tend to think that specific weight-related goals (“lose 10 lbs” or “weigh 120″) are less than ideal.
Weight Maven is written by Beth Mazur. Beth believes that obesity is more symptom than cause and that the real problem is our Western diet -- especially sugar, refined grains, and industrial oils. Beth writes about nutrition, ancestral health, & food policy. And cats! 
But I love semantics!
It seems like the problem with ‘goals’ as defined above is that when people set goals in such a way, there’s nothing beyond the time horizon of achieving it. Or worse, they already acknowledge that their behavior will change after hitting that milestone, and somehow that’s okay with them. For instance, planning to have a massive splurge after the end of a diet.
But what if we rework the meaning of ‘goals’ to encompass what you do after the achievement? Then do we have a ‘system’ for maintenance? Are all such systems necessarily good?
Some people who have very strict methods of weight control and stick to them arduously. It’s usually some grueling mix of fitness and diet regime. So they arguably have a system in place, but at the cost of the ‘robbery’ you’ve quoted elsewhere. That is, implementing it ‘at the expense of potentially more meaningful pursuits’, as you put it.
I’m wondering if the best system for a person isn’t simply that which minimizes the subjective feeling of sacrifice. Partly because that’s pretty much maximizing the subjective feeling of ease. But also because feeling, ‘I can’t eat X that I really want so that I can continue to fit into these skinny pants’ indeed distracts from more meaningful pursuits.
Not to mention the dressing up of vanity as dedication to some transcendental pursuit, as is found in some fitness circles. False dichotomies are sometimes useful: one does not usually encounter the choice of ‘superbly fit but obese’ vs. ‘looking marvelously fit but being terribly unhealthy and weak’, but I bet it’s a good question to pose to those who exult in killing it in the gym day in and day out.
Probably being really honest about one’s motivations is a good place to start for designing a viable system.