Michael Varney wrote:

I was reading an article in CNN about the percentage of overweight
and
obese people in the good old USA. The pundits and experts agree that
65%
of Americans are overweight, and 30% are obese.

Those numbers seem high- more than one standard deviation of the
population is defined as obese- but in any case, healthy people have
5-10% body fat,

Michael Varney wrote:

I was reading an article in CNN about the percentage of overweight and
obese people in the good old USA. The pundits and experts agree that 65%
of Americans are overweight, and 30% are obese.

Those numbers seem high- more than one standard deviation of the
population is defined as obese- but in any case, healthy people have
5-10% body fat, and obese people are defined as over 30% body fat. Let
the average healthy weight of an adult be 80 kg.

---- Start Fermi Problem ----

If you were to liposuction the excess fat off of Americans, estimate how
much you would get.

80 million Americans each have more than 25 kg fat, another 80 million
have around 15 kg fat. This is an excess of 15 kg each for 160 million
Americans, over the healthy amount of body fat. This is 2.5*10^9 kg
excess fat to be liposuctioned by very busy and well-compensated MDs.

If you could burn the fat for energy, for how long could you power an
average home?

Fat has 9 kcal/gram of energy. 2.5*10^9 kg of fat is about 2*10^13 kcal
or 9.5*10^16 J of energy. The US used 100*10^18 J of energy in 2002,
therefore burning all the excess fat off our bodies would power the US
for about 1 day.