Net calories - help needed

Hi,

I noticed that if I keep about 1750 cal, I have healthy meals and do not feel hungry.
On my training days (5/week), I get about 1900-2100 cals (I add about 200 cal meals of proteins). My trainings (20km run/2h weight lifting/swim 2km) are usually consuming about 1000 cal.
I am 97kg (214lb) and wish to get about 90kg (198lb) for 1m90 (6.2 feets). Am I safe or should I increase my intake?
Any idea what would be my optimum net cal on training days to lose fat while maintaining my muscles?