I am 85kg. i now jog almost every day 7km and swim 2km. for nearly a month, i have done this and stuck to 1600cals. but the scales have not changed. what is wrong?

Need Clarification: What is your height? Please calculate your bmi and see if there is a lot of fat (being in obese range) or not. Building muscle also increases the weight. We should remember that the benefit of this heavy exercise is not only measured on a "scale".

Ignore your scale: Rather than focus on your weight & bmi, consider how you feel: more energized, fitter, etc. Don't forget that while you lose weight, you will also be gaining muscle such that your net weight might not budge. However, your body fat percentage will certainly drop as your total muscle mass increases. Consider using a bioimpedance scale that measures body fat, too. It's a nice approximation to monitor.

I/O: Many calories expended (output), but we don't know about calories input. Also, we don't know fat percentage. If fat is being "burned off" and replaced with muscle, muscle ways more.