SSP Raghubir Lal gave the warning to them after he found during a recent fitness test that over 50 per cent of the police personnel are unfit and cannot run.
Lal conducted the test in public in which police personnel were asked to run for five kilometres.
The SSP, a 1998-batch IPS officer, led the race in which four superintendents of police and six circle officers also participated.
"I just saw the physical fitness of the force and all those with potbelly will have to reduce it," Lal said, adding that a cycle race would be conducted in a month to test whether their stamina has improved.