Well, start doing a reasonable amount of exercise. I use public transport all the time so that involves plenty of walking to the bus/tram stations. And also when it comes to eating, making sure eating whole foods and fresh foods would be the best solutions as they are mostly low in calories and exactly what your body needs. I wouldn't say to cut out entirely on processed food but limit the processed food to as minimum as possible

Plus, going to the gym 30mins a day would already be sufficient if you're really tight on schedule.