Originally Answered: How can I drop 10-15 pounds?
Don't target losing more than about 2 lbs per week. If you try to lose faster, your body will go into "starvation mode" and get very stingy about burning calories while at the same time very efficient about storing any calories that you do provide. And it will make you feel awful.
There is no site specific way of losing fat... the old myth about working your abs to burn belly fat isn't true. To get rid of love handles, you need to lose overall fat. That happens with exercise and watching your diet. More on that below.
The most effective way to lose fat is aerobic exercise in the "moderate" fat-burning range, ideally first thing in the morning before you eat. When you wake your body is ready to burn fat and your levels of growth hormone are highest at that time. Later in the day it can take up to 30 minutes just to put your body into a fat-burning mode.
Another overlooked way to burn fat is by lifting weights. Skeletal muscle has very high caloric needs... almost twice that of adipose (fat) tissue. Put on a little muscle and you will burn calories all day even at rest. Be aware that skeletal muscle weighs more, so with this approach you may see your weight increasing while your body fat is melting away. Not realizing this often stresses folks who think they should be losing weight as a measure of fitness. Forget the scale, look in the mirror and you will be happy.
To lose a pound of fat, you need to eliminate about 3500 calories. You can do this by burning more with exercise or by modifying your diet to reduce intake. If you do a Google search on say, "swimming calories" you will quickly find a website with tables of calories burned for a given exercise. You can use such lists to estimate how many calories you are burning up with your routine.
For diet, keep a diary for a couple of weeks counting calories, grams of protein, and grams of fat intake. It is easy with online sources of nutritional information (type the name of the food and calories into the Google search engine) and packaging labels. That will let you quickly figure out where the fat is coming from in your diet.
Fat gives you 9 calories per gram. So take the number of grams of fat, multiply by 9, then calculate what percentage the fat calories are of your total daily calories. Restricting the calories from fat to about 20% of your total intake is ideal for a maintenance diet... that isn't overly restrictive. Of note, you need some fat in your diet. For instance, the body uses fat to produce hormones. Once you have a picture of how to modify your diet, you can drop the diary and just go back to it occasionally if you are wanting to tweek things further.
There is a subset of questions that goes further and asks about "How to get a six-pack?" The answer is the same. Six-packs are 20% abdominal exercise and 80% diet. There is one caveat... abdominal muscles will form in the position that you work them, so be certain to pull them tightly toward your spine while doing crunches, etc. Also, during most lifting, the "core is active" which means that you should be stabilizing with contracted abs then too. Fail to do this and the abs will form, but bulging outward and the result is not attractive.
If you are trying to build muscle as a way to lose fat, then you may need to increase total calories and specifically your protein intake. I target about 0.8 g of protein per pound of body weight each day when actively building. That is far more protein than most people need in their diets.