It encapsulates an important fact in a pithy way: to wit, everything has a cost, and one cost of “getting into better shape” is that you will have to experience some physical pain or discomfort while exercising, and some muscle soreness the rest of the time. But "No Pain, No Gain" does a lot more for you than that.
Its catchiness also allows you to remember it instantly, so that you can repeat it and, thus, remind yourself that: (1) nothing bad is happening to you and, (2) to the contrary, something good is. The pain you feel during or after working out is a sign that you’re actually making progress toward you’re well-being! Over time, this process of associating certain pain with progress, gradually changes your attitude towards pain -- some of it you start to look for and even welcome. And this change in attitude will, over time, even change the way pain feels to you; the pain that is good for you actually starts to feel good.
Plato divided the human mind into three parts: one part strives to feel pleasure and avoid pain, one strives to get the approval of others, and another strives to do what’s actually good for your well-being. He calls the last one “reason,” and, in his terms, the slogan “No Pain, No Gain” has an important function -- it allows “reason“ to teach the part of the mind concerned with pleasure and pain (interestingly, Plato called it “the appetitive part”) to better track what’s really good for your long-term happiness.
Now with regard to getting in better shape, we are lucky that “pain” and “gain” happen to rhyme, so we have a catchy slogan to help with an important job; but this process of changing at a very basic level what does and doesn’t feel good to you is part of any difficult behavioral change. Take for example…oh, I don’t know…how about losing weight.
If you want to lose weight, you pretty much have to change your eating and drinking behavior. Exercise can help, but you have very little chance of exercising yourself into substantial weight loss or maintaining it unless you also watch what you eat. For most everyone, in order to lose weight, you are going to have to eat less.
So, what determines how much you eat? Well, in a society like ours – where food is both ubiquitous and abundant -- it’s going to be determined by whether or not you’re hungry. While lots of diets claim that you can both lose weight and never be hungry, in my experience, making and maintaining weight loss requires changing your relationship to food. Over time, you learn to appreciate a little bit of hunger in the way you come to appreciate the good pain of exercise. You start taking pride, and eventually even delighting in it a little bit. And as you learn to intuitively tune in to the role being a little hungry plays in your wellbeing -- as your most basic awareness of it becomes more holistic -- it starts to feel a little good.
For anyone contemplating losing weight, learning to actually enjoy and appreciate a little hunger may seem profound, even impossible. But, if you take time to associate hunger with a crucial wellness goal, then the change will gradually come. In Plato’s terms – which turn out to be very apt for weight loss -- reason gradually changes your appetites. And the same is true for any significant behavioral change you might be looking to make.