Eat little and often. Eating at regular intervals keeps your metabolism ticking over more efficiantly. Always have breakfast, aim to eat at least 5 portions of fruit and veg a day, more if you can manage it. Cut down or cut out caffeine as causes fluid retention and it does mess with your appetite. Drink 4 pints of water a day ~ hot water with lemon as soon as you wake up.

Most takeaway foods including sandwiches and bagels are loaded with unneccessary calories. Make your own lunch and bring it with you. It's just a matter of getting into a routine and sticking to it.

The very best of luck