Since the outlined art consists simply of filled objects, the intuitive solution would be to add an exterior stroke of the weight of half the amount you wanted to increase the initial stroke. For example, if the outlined stroke was 1pt, and you want to change it to a 2pt line, you would add a 0.5pt exterior stroke to the outline. However, some caveats I can think of off the top of my head:


Adding strokes to unjoined outlines will add weight to the ends, while with path stroke behaviour, the stroke is capped at the endpoints by default
It's a lot harder to reduce the weight of the stroke after it's outlined. Luckily, you want only to thicken it, so you don't really have to worry about this.


There's probably others — working with outlines when you want paths is never ideal. Nonetheless, the short answer is yes, it is entirely possible. You just have to be a little craftier.

can i make an outlined path thicker in illustrator?
Here is a photo of a menu in Bali, Indonesia:



The Diet Coke is 14,000 rupiah. The regular Coca-Cola, and other soft drinks, are 10,000 rupiah. It isn't just this restaurant, the same is true of virtually every restaurant I have been to.

Why is Diet Coke more expensive than regular Coca-Cola in Bali (or Indonesia, if this is not limited to Bali)?
