Calories

It turns out (and I have done research) that walking and running use up the same number of Calories.  It doesn't matter whether you walk a mile or run a mile.  You will burn the same number of Calories.  The number of Calories burned is 100.  Of course, if you run, you will burn Calories faster, depending on how fast you run.  If you do a 6 minute per mile pace, then you will run ten miles per hour and burn 1000 Calories per hour.  If you walk three miles per hour, then you will burn 300 Calories per hour.  But the number of Calories per mile seems to be rather constant.
Also constant is the amount of Calories contained in a pound of fat.  That would be 3600 Calories in a pound of fat.  If you are fat, then each pound of fat on you was put there by your eating 3600 Calories.  If you want to lose a pound of fat, you would need to eat 3600 Calories less, or exercise the equivalant of 3600 Calories.
Thus, to lose a pound of fat by exercise alone, you would need to walk for 36 miles.  This may seem like a lot.  It may seem far.  But it doesn't need to be done all at one go.  You could walk 1.2 miles per day for 30 days.  This would be a pound a month.  Twelve pounds a year.  And 120 pounds in 10 years.  Do you intend to be around in 10 years?  Then make plans!
Actually, an hour walk is three miles or 300 Calories.  So if you walk an hour per day, that should burn about three pounds per month.  36 pound per year. 
So why are so many people so fat?
Obviously, it is also a matter of eating too much.  You can eat a lot in very little time if you want.  For example, a burger with fries and a shake - say 1200 to 1500 Calories.  That's 12 to 15 miles.
Of course, everyone burns some Calories even if he or she doesn't walk.  The number ranges from 1800 Calories per day for smallish women, to 4000 per day for muscular men.  This number is dependent on the weight of your muscles in your body.  Fat doesn't burn any Calories at all, at least not enought to be a factor.  So even if you do not exercise, your body still burns a number of Calories.  But if you exercise, the number of Calories burned goes up according to the amount of exercise.
That is why you warm up when you exercise.  The Calories that you burn are almost all turned to heat energy. 
The definition of a Calorie is the amount of heat necessary to raise one liter of water, one degree Centigrade.  In approximate terms, your body volume (of water) is the equivalent to your weight in kilograms (divide your weight in pounds by 2.2). 
Normal body temp is 37 degrees Centigrade.  Average weight is 100 kilograms (not really, but it will make the calculations eaiser, and anyway, 100 kg is 220 pounds, so if you are just a little bit overweight, you may eaisly weigh 100 kg.)  So if a 100 kg man walks one mile, he will raise the temperature of his body by one degree to 38 degrees.  Obviously, his body temperature is regulated by body mechinism (sweating, etc) so his temp remains a constant 37 degrees.  So where does the heat go?  If he was cold before, cold hands or cold feet, then they are warmed up.  If he was already warm, then the heat leaves the body somehow.  Or eventually he will die of heat exhaustion. 
A person who is sitting and is comfortable is still losing heat to outside the body.  If he burns 2000 Calories per day, that means that each hour, on average, he burns 2000/24 Calories.  (83 per hour)  But you burn less when sleeping, so if you burn 50 Cal per hour sleeping for 8 hours, that is 400 Cal.  And so that leaves 1600 Cal for 16 waking hours, or 100 Cal per hour.  So our comfortable person, sitting, is really buring 100 Calories per hour, and those would raise his temp up one degree Centigrade if all the heat created would be contained and not released.
That is why you get warm when you exercise. 
So, with me, I am about 110 pounds overweight, I think.  That would be 50 kg.  And that would be about 400,000 Calories or about 4,000 miles.  Walking 4 miles a day, that would be 1000 days or about three years.  Ok, let's get going!!!!!!!