The immediate short-term cost of skipping workouts or making poor food choices is insignificant. And we tend to ignore the long-term costs because it’s not tangible.
That, and we’re notoriously bad at long-term thinking.
One way to get a glimpse into the long-term costs is to observe folks who are 20, 30, or 40 years of your senior. Look at people who’ve ignored their health and fitness most of their life. And compare them to people who haven’t.