I'd choose red. My reasoning:
- I already get plenty of sleep, so no yellow pill
- I rarely get sick, so no pink pill
- I enjoy food, so I'm fine with needing to eat, meaning no green pill.
- If I aged 2x slower, I'd have to watch everyone I know die. That would be awful, so no grey pill.
- Orange pill isn't much of a benefit, other than the ability to survive underwater or anywhere there is no air.
- Blue pill isn't really a huge benefit either, what do you gain by not needing to drink water? Unless you live where water is scarce, it's not a big deal.
- Black pill was tempting, but I'd choose red because then, no matter how much I eat, I'd always be fit. That way, I can enjoy the flavour of food without becoming 500 pounds. It also means I can eat as much candy and ice cream as I want!