Loss Energy

How do you work out the rate of loss of energy?
I need the equation to be able to work out the rate of loss of energy using time.
Thanks.
You seem to be talking about power?
P = d(E)/d(t)
Power = (change of energy)/(time required for change)
http://www.physicsclassroom.com/class/circuits/u9l2d.cfm
http://www.google.com/search?hl=en&source=hp&biw=1144&bih=699&q=rate+of+loss+of+energy+with+time+equation&aq=f&aqi=&aql=&oq=&gs_rfai=
ALKALINITY Weight Loss and Energy
Category: weight management