The interesting parts:
That the conventional wisdom of 3,500 calories less is what it takes to
lose a pound of weight is wrong. The body changes as you lose.
Interestingly, we also found that the fatter you get, the easier it is
to gain weight. An extra 10 calories a day puts more weight onto an
obese person than on a thinner one.
Also, there’s a time constant that’s an important factor in weight loss.
That’s because if you reduce your caloric intake, after a while, your
body reaches equilibrium. It actually takes about three years for a
dieter to reach their new “steady state.” Our model predicts that if you
eat 100 calories fewer a day, in three years you will, on average, lose
10 pounds — if you don’t cheat.
One of the things the numbers have shown us is that weight change, up or
down, takes a very, very long time. All diets work. But the reaction
time is really slow: on the order of a year.
People don’t wait long enough to see what they are going to stabilize
at. So if you drop weight and return to your old eating habits, the time
it takes to crawl back to your old weight is something like three
years. To help people understand this better, we’ve posted an
interactive version of our model at bwsimulator.niddk.nih.gov. People
can plug in their information and learn how much they’ll need to reduce
their intake and increase their activity to lose. It will also give them
a rough sense of how much time it will take to reach the goal.