On the topic of "weight loss is all about calories" - there was a college professor who did a "twinkie diet" to illustrate losing weight is all about calories in and calories burned and not what you eat...
http://www.cnn.com/2010/HEALTH/11/08...sor/index.html
Also, initially it is easy to lose weight because your body first burns glycogen - which has water bound to it. So you lose the energy store + water weight at first...
Details from the mayo clinic website :
"During the first few weeks of losing weight, a rapid drop in pounds is normal. When calories from food are reduced, the body gets needed energy by releasing its stores of glycogen, a type of carbohydrate found in the muscles and liver. Glycogen holds onto water, so when glycogen is burned for energy, it also releases the water ? about 4 grams of water for every gram of glycogen ? resulting in substantial weight loss that's mostly water."
So you are not doing anything "wrong" when the weight quits dropping as fast after 2-3 weeks - it's just how the body works through what it has stored up....
The other thing that comes to mind is the injury/recovery cycle that I have gone through while getting myself back into shape. As we get older - it's easier to injure/strain something and takes much longer to heal up. This interrupted my workout routine several times. Hence the advice on getting a good warmup, etc.
Jeff
p.s. If you want some motivation to lose weight and drastically reduce your risk of coronary artery disease (plugged up arteries that supply your heart) - search on CABG (coronary artery bypass graft) or open heart surgery on youtube - and watch a doctor open up a guy's chest with the equivalent of a sawzall and a car jack... Trust me - it sucks...