The body has usable energy reserves of about 2000 calories, so should comfortably handle a 600 calorie workout.
However, I would think that you are burning SIGNIFICANTLY more than 1700 calories per day.
It is generally reckoned that a sedentary lifestyle burns around 20% in addition to your BMR through daily NON-exercise activities. As a PE teacher, this is more likely to be 30-40% in addition to your BMR. Focussed workouts would be in addition this again.
So your total burn would be BMR (1700) + 30-40% (510-680) + 600 = 2810-2990.
If you continually run down your reserves through eating significantly less than your overall energy expenditure, then it is likely that this will show up in less-than optimal performance.
Also, when faced with a large calorie deficit, your body can try to close the deficit by slowing your metabolism, sacrificing muscle to preserve fat, etc. Not only is this unhealthy, but the muscle loss makes your long term performance gains harder.
If you are looking to maintain your weight but improve performance, then you should definitely be eating more. If you are concerned about gaining weight, try increasing to 2200 and see what happens then.
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.
| current weight: 178.0