Your habits of your 20s and 30s could significantly impact your 40s and 50s. Taking care of yourself means enjoying more great moments later on too. Also, taking care of yourself can be in itself enjoyable. Pick up a sport, or if you're not competitive, make going to the gym a social thing. And eating healthy can certainly be tasty.
[1]: https://data.worldbank.org/indicator/SP.DYN.TO65.MA.ZS?locat...