Can someone give an explanation of the process of weight loss? (this is not a &q!

Can someone give an explanation of the process of weight loss? (this is not a "how do I lose weight" question)

So I have been hearing many different explanations concerning how weight is actually lost, and I would like to clear up the misconceptions that I might have. For example, one person told me that the only way that one can lose weight is to burn more than is taken in daily, which seems nearly impossible unless you want to eat nothing but celery and work out for hours. Another thing I have heard, however, is that an actual pound is equal to about 3000 calories, and every time that amount is burned, a pound is lost. So basically, I run for about 25 mins 5 times a week and apparently burn around 200 calories each time. Is it true that every time these instances of 200 calories burned add up to around 3000 a bit of weight is lost? Could someone tell me how it truly works, because in all honesty, I really am trying to have a healthier lifestyle but as of right now it seems impossible to do and I am getting discouraged.(I am 5'7 and weight about 150 and would love to lose about 15 pounds)

Actually what you heard is correct, you can only lose weight, and I assume we are not talking about water weight here, by burning more calories than you take in. Unless of course you are going to pay a plastic surgeon to suck it from your body, or alternatively cut off a limb, however, you're missing the key factor, which is your metabolic rate. The reality is your correct in regards to you burn x amount of calories while your running, the thing your missing is what that does to your metabolism. Your body continues to burn calories long after you finish running. Your temperature is up, your body is trying to cool itself down, and you will continue to burn additional calories long after you're finished. On top of all that you burn calories while you're sitting around doing nothing.
The general rule of thumb, this is an average, and unfortunately I don't have a site that I can point this to, so take it for what is it is worth Woman multiple your weight by 11, men by 12, yes I know it isn't fair, and that is how many calories your burn at rest. This obviously changes as your body composition changes, more lean muscle burns more calories, higher metabolism, but for the purposes of simple math we will stick with the average. Based on that, a 150 lbs woman burns 1650 calories sitting around doing nothing, then throw the 200 for your daily run, and just for simplicity sake lets say your body burns an extra 100 calories over the next hour trying to cool it self down, and you're up to 1950 calories burned in a day. Now I have already heard that 1 pound of stored fat is 3500 calories, again sorry no reference, and I am too lazy to go look it up, sorry. In any event, if you are only eating 1500 calories, I am NOT suggesting this, just simple math here, then our example is burning 450 calories extra every day, which equate to losing around a pound of body fat, not weight because your body stores water and you will lose that as well, per week. So the most effective way to continue to lower your body fat is to burn the number of calories you use at rest, yes this includes while you're sleeping. This is where weight training can be very useful, but that is for a different post. Hope this helps.