The main cause of bad breath is formation of plaque/ tartar. Removal of this by scaling every 6 months and subsequent daily twice brushing would help you. Try to avoid any intake for at least 4 hours. Try to avoid eating raw garlic n onions which also cause bad breath.

To reduce or prevent bad breath: Brush your teeth after you eat. Keep a toothbrush at work to use after eating. Brush using a fluoride-containing toothpaste at least twice a day, especially after meals. Toothpaste with antibacterial properties has been shown to reduce bad breath odors. Floss at least once a day. Proper flossing removes food particles and plaque from between your teeth, helping to control bad breath. Brush your tongue. Your tongue harbors bacteria, so carefully brushing it may help reduce odors. People who have a coated tongue from a significant overgrowth of bacteria (from smoking or dry mouth, for example) may benefit from using a tongue scraper. Or use a toothbrush that has a built-in tongue cleaner. Avoid dry mouth. To keep your mouth moist, avoid tobacco and drink plenty of water — not coffee, soft drinks or alcohol, which can lead to a drier mouth. Chew gum or suck on candy — preferably sugarless — to stimulate saliva. If you have chronic dry mouth, your dentist or physician may prescribe an artificial saliva preparation or an oral medication that stimulates the flow of saliva. Adjust your diet. Avoid food and beverages that can cause bad breath. Avoid sticky, sugary foods. Regularly get a new toothbrush. Change your toothbrush when it becomes frayed, about every three to four months, and choose a soft-bristled toothbrush. Schedule regular dental checkups. See your dentist on a regular basis — generally once or twice a year — to have your teeth or dentures examined and cleaned.