As for what they can eat (Fruit, Veg and Herb)
Alfafa
Apple (seedless)
Asparagus
Avocado (skinned and seedless)
Banana
Basil
Blackberries
Blueberries
Broccoli
Brussel Sprouts - small amounts occasionally - not all hamsters like the strong taste
Calabrese
Cabbage - should only be fed in small amounts occasionally as too much can cause health problems
Carrots
Cauliflower leaves and stalks
Celery
Cherries - stones should be removed as they can be dangerous if gnawed
Chestnuts
Chicory
Chinese Leaves
Coriander
Corn-on-the-Cob
Corn Salad
Courgettes
Cranberries
Cress
Cucumber
Curly Kale
Dates
Endive
Fenugreek
Feijoa
Figs
Grapes
Green beans
Kale - should only be fed in small amounts occasionally as too much can cause health problems
Kidney Beans (cooked)
Kiwi Fruit
Kumquat
Lettuce - small amounts occasionally - in excess it can cause liver problems
Logan Berries
Lychee
Mange Tout
Mango
Marrow
Melon
Mint
Mung
Okra
Pak Choy
Papaya
Parsley - a good tonic
Peach
Pear
Peas
Plums - stones should be removed as can be dangerous when gnawed
Potato (cooked)
Raspberries
Raspberry Plant leaves - beneficial for diarrhoea
Rhubarb (cooked)
Rocket Chard
Sage
Sorrel
Squash
Star Fruit
Strawberries
Sugar Cane - small amounts
Sweet Potato
Soybean Sprouts
Swede
Sweetcorn
Sweet Peppers
Ugli Fruit
Turnip
Water Chestnuts
Watermelon
Water Spinach
And what they can't eat:
Kidney Beans (raw)
Onion
Potato (raw)
Potato tops
Rhubarb (raw)
Rhubarb leaves
Tomato leaves