Look on any fat foot's nutritional info; you'll
see that each gram of fat has 10 calories.
This means 1 kg of fat = 10,000 calories.
(Actually they're kilocalories, so that's 10
megacalories, but some genius decided
that 1000 energy calories = 1 nutrition calorie.)
A "normal diet" for a "normal man" is 2000-2500
calories per day.
That means that, if you ate /nothing/ for 4-5 days
and didn't exercise more than an "average man",
you could lose at most 1 kg of fat. In fact you
would lose some fat and some muscle, so things
aren't even that good. Under extreme conditions,
such as, oh, Airborne Ranger training, you might
consume 5000 calories a day IIRC, but you would
have to eat a lot to even remain standing
by the end of the day.
So it's a slow process. It probably took years to
build that tire; it'll take more than 1.5 months
to get rid of it.