Here are a few more suggestions.
* Start at the Vidhana Soudha, walk through the Attara Katcheri, GPO, King Edward Statue, down Queens road till the Queen Vic statue, continue on MG road past the bookstores and St Marks Church, all the way to Trinity Circle. End at the Trinity Church. Eating options abound and cater primarily to the tourist crowd. A little off the beaten path are Sunny's (an Italian rest on Lavelle Rd Cross), Queens (a roti place on Church St - behind MG Road). Also take a detour off Brigade road, to visit the Select bookstore on Brigade Road Cross.
* Malleswaram. Start at the intersection of 18th Cross and Sampige Rd, walk about 5 kms to the Malleswaram circle. Totally different perspective of BLR as compared to what you see on MG Road etc. Eating options abound - Asha sweets on Sampige Rd caters to your sweet tooth. There are other eateries along the way, most are traditional. There's a Pizza joing about 1 km down from 18th Cross/Sampige Rd.
* There are a few other walks in and around Jayanagar. e.g. Walk from the Lalbagh Garden to Jayanagar 4th Block shops and eat at either the MTR (Mavalli Tiffen Room) or the Dosa shops near 4th block shops.
* I am sure someone can suggest walks around Commercial Street, City market or Russell Market - but those are not for the faint of heart. Also pickpockets abound in those areas and you are better off with a local friend.