I bought a jar of marinara sauce a couple weeks ago. I just opened it and used some of it. Much more watery than I'm used to. I didn't check the nutritional label but marinara sauce is a mix of solids and water. So it seems like they've lowered costs by decreasing the solids.

Same thing sometimes happen when you buy uncooked ham or turkey: they often inject it with a lot of salt water ("up to 8% brine solution") to increase the weight without increasing the actual product.