A diligent dieter and I worked together in state government about 25 years ago. He had two obsessions that I knew of, food and government waste.

While pounding carrots and celery sticks, sans dip, at an Albany reception one night, he shared with me a eureka moment he had just experienced.

“Bureaucracy is like a fat cell,” he exclaimed, as if wanting to alert the room to the breakthrough insight. “Once a new one’s created, it’s impossible to get rid of it. You can shrink the thing, but it will always grow back. Expansion is its nature!

“Hey, are those Cheetos?”

It was hard not to recall my friend’s hypothesis when news broke this week of NYC’s surprising contract with the belt-tightening giant Weight Watchers.

No, silly, City Hall’s not going on a diet; it’s spending $6.6 million over the next three years to try to slim down 300,000 members of its workforce. The program is first come, first serve, so corpulent procrastinators on the municipal payroll are plum out of luck. For now.

The city swears this idea will save taxpayers money on health care costs in the long run. Fat chance. What it will do is set a precedent for another area of government expansion — molding the personal habits of employees — in the name of fiscal savings.

If the city is paying employees to get dietary counseling, why isn’t it paying for them to turn off the TV, drink less beer and join gyms? (It already pays for condoms and nicotine patches.) Why should Weight Watchers get an exclusive contract when 100 yoga studios in the boroughs can convincingly argue that they could reduce employee sick days with some simple chillaxation techniques. Ten sessions and those traffic cops could double their ticket-writing.

Then there’s the administration of it. Won’t the city need to measure the success of its Weight Watchers experiment? The Office of Diminished Rotundity has a nice ring to it. It could start with a budget line of, say, not a dime over $10 million annually. Plus the psychiatric team. Gaining weight after losing it can put a real hit one one’s self image. Don’t laugh. It’s enough to start one smoking again . . .

Pass me another Cheeto.

William F. B. O’Reilly is a consultant for Republicans.