Smita, it seems you have spoiled ( though inadvertently ) your dog's habit. As mentioned, you are feeding almost everything to your pet, ie fruits, chicken, roti, dog food, yogurt, etc. Like, humans, dogs also become choosy in eating and they'd eat what they like the most. You are feeding a lot of things to your dog and that's not required. If you want to feed commercial food, then you shouldn't feed home-cooked food, if you are feeding home-cooked, then you don't need to feed commercial food.
By keeping so many options, you have not just confused yourself, you have also confused your pet!! Just follow a basic rule: Schedule the feeding timing of your dog - 7:00 AM in morning, 3:00 PM in afternoon and 07:00 PM in evening. This is just an illustration. You can customize it as per your situation.
Keep the food in the boil for 10 minutes, take the food off and feed it the next time. Don't let the food stay on the bowl. Don't add things to entice the dog into eating. Keep the food for 10 minutes, wait for her to finish and remove the bowl. By doing this, you are reinforcing a good habit. Your dog will learn that it has to eat it, whether she likes it or not, to soothe the hunger.
You should take the dog to the vet after every 3 months, get her weight checked. Female Labs should weigh between 32-35 kg. But, weight can also vary according to the pedigree of the dog. For example, should quality dogs weigh more than their working counterparts. But the bottom line is your dog should never be over-weight.