We're starting reviews of supermarkets because really, you shouldn't be eating out so much.
Keells Super at Crescat Mall (in the basement to be precise) is one of the most internationally patronized in the city. A whole range of westerners and Asians, many of whom live in the semi-attached apartments nearby, patronize this Keells. As such, they have one of the cities best selections of cheese, meat and condiments, though their fruits and vegetables are nothing special.
No lie, they have a lot of cheese, and good cheese is hard to find in Sri Lanka. The cheese, however, is quite expensive, over Rs. 1000 a wedge.
They also have a good range of condiments, from Hellmann's mayo to various sauces. Again, expensive, Rs. 600 and up, Rs. 1000+ for most items. This Keells also has a good selection of instant ramen noodles and Sri Lankan spices as well.
They also have liquor, a pharmacy and a lot of consumer goods (hair products, soaps, etc). It's also situated within a mall, so a lot of stuff is available nearby. Note that Keells Super also does online ordering and delivery
While the Crescat Keells an impressive range of cheeses and condiments, those are expensive and their fruits and veges are nothing special.
They have a lot of cheese for a lot of cheddar.