Eating in paris and en london is not cheap, you should look for mcdonalds and little restaurants, you will spent +/- 8€ for meal…

The bear is more expensive in london so is better buy a lot in other towns

Sorry for my english and good luck in your trip

Just don’t eat in the touristy areas.
Picnic at the open markets.
Check out what’s offered at grocery stores.

LONDON – Most pubs are corporate owned and beer prices are the same. Look for daily specials as you walk buy the pubs and drop in and ask the locals. The staff at your hostel should know the cheapest beer in town. One corporate chain called JDWeatherspoons owns pubs all over London. Banners are hung up outside offering specials on drinks and food. They offered following prices in central London in 2009, (using 1.60 exchange rate) Lowest prices was Pints of Abbot Ale & Marston’s Pedigree for 1.99GBP ($3.18USD) Pints of Fosters, 1664, Stella Artois 2.30-2.70 ($3.60 – $4.32USD) Guiness was 2.60GBP ($4.15USD) They also offered a Traditional English Breakfast till noon for 1.99GBP ($3.18USD) In past years they had 2 dinners for 7.95GBP and in 2009, they offered one dinner for 3.99GBP ($6.38USD) good time to try Fish-N-Chips and wash it down with a cold ale or bitter.
The local TESCO supermarkets had good meal deals if you shop around and read the signs. You could get a cup of pasta, a bag of crisps (potato chips) and a drink for only 2.00GBP ($3.20USD) They also had many 2for1 deals that will save you money. Best deal is Tesco water 2 liters only .35pence ($0.56USD). McDonalds combo meal 3.79GBP ($6.06USD). Burger King cheeseburger meal deal with small fry & small coke was 1.99GBP ($3.18USD).
Pret-A-Manger sandwich stores (all over London) offer triangle sandwiches, wraps, bowls of hot soup from 1.39 – 2.89GBP ($222.00 – $4.62USD).
Try out the Cornish Pasties and sausage rolls served hot from 1.50- 2.40GBP. Stop by a pub after 4pm and ask all the working people where they go to eat,.
PARIS – Great outdoor markets, produce stands, bakeries and many small markets. If you have good weather, hit the local bakery and markets and purchase food and find a good spot for a picnic at Champ du Mars (on the grass in front of the Eiffel Tower), by the river at Notre Dame and on the lawns in front of Sacreu Coeur. Many cafes offer menus in English and menu means the special on the chalkboard that gives you up to a 3 course meal for 10.00 – 20.00 Euros ($20.00 – $30.00USD). Enjoy Paris by getting in line with the locals at the bakery, picnic in the parks or after exhausting museum visits. Be prepared, pack a bunch of food and water in your daypack each day so that you don’t get screwed on prices at the tourist stand next to the monuments and museums. In the markets, you can get a fresh baguette, meats, salami, pre-mixed salads, cheese and fruit and have a heathy and reasonable meal with great views. Trendy bars are very expensive in Paris. Stop by the small minimarkets and get cold beers or stop in at small family run local cafes off of the main street for cheaper prices.
AMSTERDAM – Since many tourists will be smoking and drinking, the munchies will be the most popular items. Small snack shops are everywhere especially in the Red Light District and heavy tourist areas. Their food looks great when you are stoned or drunk, but taste like crap, especially the fried items the the local Febo. The markets also have good deals on sandwiches and snacks. Like all cities, the most popular places for backpackers are the Gyros/Kebab shops that are open very late and run 2.00 – 4.00 Euros. ($3.00 – $6.00USD) Amsterdam is also known for french fries sold in paper cones with mayo, one of many choices for sauce.
McDonalds, Burger King, Subway and KFC are offering lower priced menus throughout Europe but you will never see a dollar menu. Stay away from fast food and hit the local markets for better options. For those going to Munich the Main station has a huge food court at the end of the tracks and downstairs on your way to the S-bahn. Reasonable prices and great sausages after a night of pounding beers.
HAPPY TRAVELS!