The best tip I have for anyone seeking a healthier lifestyle is to move every day.
High intensity training (especially interval training) does burn fat quickly, but strong research is accumulating that shows those with non-sedentary jobs live longer than sedentary employees who run marathons on the weekends. People who move regularly have better health measures than people who move intensively but infrequently.
If you have a desk job, set a timer for somewhere between 22 and 60 minutes. (22 minutes is how long our brains can focus exclusively on one task) and take a stretch break, walk around the office, or simply change positions (sitting versus standing, regular chair vs. seated on an exercise ball).
Another trick that works: Fill up a 2 liter glass bottle with water or unsweetened herbal tea the moment you get to work. Aim to sip on it throughout the day. You will stay hydrated, eat less, and get up plenty frequently for bathroom breaks :).