Gingr has given you some marvelous ideas that I fully endorse. Granted, it is easier to purchase pet food but you can develop a diet that is balanced and nutritious from what you are eating. Once a dog gets that taste for something it likes, it often takes gentle, prolonged persuasion to get it to try something new. Even if the proprietary food is not of premium quality, you might still need to use it as a base of what you feed your mixed breed dog. Dogs are carnivores so keep the diet meat based. Ginger was correct is recommending various vegetables. Some dogs like them cooked. Some raw. Experiment to find what your dog likes.
The transition to any new food should be gradual. Add the new to the old in slowing increasing increments. Sometimes it is necessary to be more stubborn than your dog. He may need to go a bit hungry for a day or two until it realizes that you mean business.
There is an internet site called Balanceit.com. For a fee, a board certified veterinary nutritionist can help you formulate a diet with ingredients that you have access to.
Best of luck ....
I don't like jumping in here ahead of the vet! But never mind.... The vet can always push me sideways! lol!
Lean chicken is fine for dogs. Vegetables, like carrots, green beans, peas, are OK for dogs too. But dogs really need as basic nutrition, a good quality dog food with all the right balanced minerals and vitamins, and adequate protein. There are very many good foods on the market, without additives and preservatives, etc, or animal by-products. In England (where I am) we have slightly different products than in the US, but a little research online may point you towards the right food.
A little white bread and tomato is not a balanced diet suitable for dogs. See if you can get her interested in a good food. If it's a kibble-type, you may be able to use single pieces to use as treats, to get her interest, so hopefully, come dinnertime, she will be used to the taste of it. But don't feed her more than twice a day. She needs a good appetite up, in order to enjoy the food. If she's an active dog, she ought to have a good appetite. Make sure she definitely does get the exercise and play she really needs.
As for drinking water.....my dog has times when she won't drink as much as she should, then times when she drinks OK. During the 'bad' times I will give her unseasoned chicken or meat stock, just to make sure she does get the liquids she needs, and that works. There have been times when I have had to painstakingly get her to drink water from my hand! Then the next day she is back to normal again! It is a mystery, as my dog is fit and well. This has been going on for years!
You could also try adding some thin gravy (unsalted) to her food. Add it at the last minute so it won't make the kibble squishy.
If her appetite does continue to be poor, then a visit to the vet is a good idea, to make sure she hasn't got any health issues going on.
@ginger thank u for ur reply....
i m from india and we dont get very good proprietary dog food in india...os i have to give her normal indian curry n indian breads...still wat u suggest i shud give her...give me a good combination type of thing...n she loves to eat ice cream...shud i give her ice cream...?