Here's a list of a few places within 4kms of IISc.
Mast Kalandar (North Indian Vegetarian),
Mint Masala (North Indian),
Vegetarian), Pizza Hut, Chung Wah (Chinese)
Gold course Road
Le Brassiare at Le Meridian (Multi-cuisine), Dakshin at Windor
Manor (South Indian)
South Indies (South Indian Vegetarian), Samarkand (Afgan)
Millers 46ers (Steak house), restaurants at the Sigma Mall, PizzaHut
Hunan (Chinese), KFC, McDonalds
A little farther from IISc is the Church Street area, which has over 50 restaurants of all kinds.
The website www.hungrybangalore.com has a listing of most restaurants in Bangalore and lets you order takeaways online.