Thanks for raising the query on this platform. From whatever little information and to that you have provided, I believe that the possible causes could be either
1. calculus formation, due to improper Brushing Technique or negligence in cleaning.
2. mouth breathing habit
3. maybe the food is getting lodged the interproximal spaces and over a period of time this starts to emanate foul smell.
I would recommend you to visit nearest dental centre and get your oral hygiene status accessed and accordingly the dentist will be able to guide you in a better manner after seeing the condition of your oral apparatus.