Minimize the food supply for bacteria . The anaerobic bacteria that cause bad breath feed on protein rich foods . Vegetarians who eat less protein foods have much less problems with bad breath . Using mouthwashes too often can not always be that good for you as they contain chemicals , however you can use a mouthwash of baking soda dissolved in water daily without any risk .

Question: What may be the reason for them giving these tips ?
Answer: None of the above choices .Someone wanted to make their breath fresher .Someone wanted to become a vegetarian .Someone wanted to know the pros of quitting meat .