First step in exercise is to always Think FIT. To make physical improvements, you need to work your body harder than usual. This is referred to as the overload principle. As your body becomes more conditioned, you need to increase the frequency, intensity, or time of your workouts in order to continue improving your fitness level

Choosing an Exercise:
The best exercise is an activity that you enjoy enough to really pursue enthusiastically.
•Indoor (Facility) Activities: If the treadmill, stairmaster, rowing machine or stationery cycle doesn't excite you, sample some group activities that strike your fancy. Participate in a group cycling class, beat stress with yoga, find balance with martial arts, stay cool with indoor swimming, or kick some you-know-what with boxaerobics.

1. Change your eating habits (i.e. start eating smaller portions of food) before if you ate a full plate of food try eating 2/3 of a plate instead.
2.
o Substitute aspartame for sugar
o Try eating 3 or 4 smaller meals during the day rather than 2 large ones
o Eat your main large meal at midday with the other meals much smaller in content
o Don't eat heavy meals late in the evening as the body wont have time to digest it so it ends up stored as fat in your body.
o Balance your meals out during the day so in one day you have a mix of protein, carbohydrate and vitamins
o Drink lots of water during the day and before, during and after exercise, you should drink at least 8 big glasses of water per 24 hours
o Drink alcohol in moderation
o Stop smoking if you smoke or cut down
o Eat more fibre i.e. pulses grains nuts, pasta, brown rice, cereals, fresh fruit
o Eat more vegetables as part of your diet
o Eat less dairy products or choose those with less fat content i.e. cottage cheese
o Try steaming or poaching food instead of frying it, frying adds calories by the bucketful
o Cut down on Red meat and eat more lean or better still chicken and fish instead
o Use low fat oils in cooking i.e. sunflower, corn or Mazola
o Cut down on your salt intake, there are hidden salts even in tinned foods
o Try substituting carrots or fresh fruit instead of biscuits and sweetmeat when you have a craving for something in between meals.
o Drink semi or skimmed milk as opposed to full cream
Simply choose a diet which is low in fat and cholesterol, moderate in sugar and salt and high in fibre but at the same time has a variety of everything thus making it a balanced diet.

Calculate your BMR!!!!
BMR means Basal Metabolic Rate.It is used to estimate how many calories you should consume.By using a simple formula called the Harris-Benedict principle, you can assess your BMR.
Your BMR is the amount of energy your body needs to function.Then, to lose weight, you'll need to cut calories or burn extra calories and shoot for a level lower than the results you get with this formula.
We use about 60 percent of the calories we consume each day for basic bodily functions such as breathing.Other factors that influence your BMR are height, weight, age and sex.
Step One : Calculate your BMR with the following formula:
•Women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
•Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)
Step two : In order to incorporate activity into your daily caloric needs, do the following calculation:
•If you are sedentary : BMR x 1.2
•If you are lightly active: BMR x 1.375
•If you are moderately active (You exercise most days a week.): BMR x 1.55
•If you are very active (You exercise daily.): BMR x 1.725
•If you are extra active (You do hard labor or are in athletic training.): BMR x 1.9
Create a Calorie Deficit:
In order to lose weight, you must create a calorie deficit. It is easier and healthier to cut back your calorie intake a little bit at a time.
Every 3,500 calories is equivalent to 1 pound.
If you cut back 500 calories a day, you will lose 1 pound per week.
If you exercise to burn off 500 calories a day you will also lose 1 pound per week.
Ideally, you should do a combination of both, (e.g. cut back 250 calories; burn an extra 250 calories).

For more useful information go to
read the following articles
References :
http://informationquest.blogspot.com/2006/12/always-think-fit-first-step-in-exercise.html
http://informationquest.blogspot.com/2006/12/what-is-your-bmr.html
http://informationquest.blogspot.com/2007/04/secret-to-fast-metabolism.html
http://informationquest.blogspot.com/2007/05/physical-activity-in-your-daily-life.html
http://informationquest.blogspot.com/2007/06/exercise-ratings.html

13 year olds should not be dieting for 10 pounds. It's not because I'm an evil adult who wants to keep you from being happy, it's because you are still growing, and a diet now can have serious long-term effects that will change your relationship with food and weight in a bad way for the next 50 years (or so). A diet at your age (when your body needs a TON of calories - more than an adult), can cause you to gain weight more easily as an adult, stunt your growth, and cause permanent changes to your metabolism. 10 pounds is NOTHING when you are in puberty… it could just be your body gearing up for a growth spurt. You did not mention what your height is, and that can be a HUGE factor in determining how much you should weigh.

Meanwhile, concentrate on healthy habits - eating right (food pyramid link below), and regular exercise. If you still think you need to lose weight, see your doctor, and (s)he will get you in touch with trained professionals who are experts in teenage physiology.
References :
http://www.mypyramid.gov

In fact, using this method can and often DOES produce visible weight loss results in as little as 10 days or less.

If you need to know how to lose weight quickly then this article will be your saviour. But before I set you in the right direction, I must say that quick weight loss (aka yo-yo dieting) is NOT a healthy way to carry on eating.

Lecture over! Now let's shed those pounds off your body so that you're left with a lean, sexy shape in ultra quick time, ok?

There are actually several approaches that people take to lose weight very quickly. Celebrities use very dangerous yo-yo diets where they go from normal calorie consumption to things like Lemon Tea for breakfast.

Well, forget that. Too much torture!

So instead, I am going to share with you and focus on the single most effective fast weight loss technique that, when combined with a proper system can see you lose A LOT of weight in as quickly as 10 days or less, but more to the point, it will not be anywhere near as difficult as those flimsy and bland celebrity diets…

It's called "carb rotation".

Carb rotation is a short term diet strategy that consists of three key elements:

1. Huge CUT on your usual fat intake

2. Limiting your overall carbohydrate consumption

3. Boost your protein consumption

We all know the first element is pretty obvious, because fat will have no place in our temporary quick weight loss plan. Lose the skin on chicken, put oil to one side and leave out the butter whilst losing the weight this way.

Next, you'll see that I mentioned limiting you carbohydrate consumption. Again, this sounds obvious…but it's important that it is done right because by properly limiting your carbs, you will suppress the release of insulin in your body.

Insulin helps the body to store fat more quickly, so by limiting carbohydrates you shut down the supply of insulin, therefore increasing fat loss rather quickly and rather effectively!

(And who said weight loss was hard work huh?)

Finally, you'll notice I mention adding extra protein to your diet. Now this is actually more important than you might think. Because during your quick weight loss, if there is no added protein, your body will start eating into your muscle tissue.

This is BAD NEWS because it can not only make you weak but will also give a very unhealthy, un-toned appearance of contours around your body due to a slight loss of muscle tissue.

You might feel weak during the first few days to weeks, because the body will go into a stage of ketosis. This is due to the sudden loss of protein and fats.

This can be avoided with proper expert guidance, but as we're not in a position to hire a personal nutritionist or have the time to mess around scouring advice from each corner of the internet and desperately trying to build a safe plan to lose weight quickly and safely, there is a better (and even quicker and more effective) option available to you!

Because if you're serious about losing weight in as little as 10 Days, then you need to see how to make this carb rotation diet work for you via a proper easy and super quick system.

Therefore, I would suggest taking a look at my #1 recommendation for the internet's best selling carb rotation program online here:

http://trustusreviews.com/carbrotation

See for yourself how it can easily take you by the hand and make you lose weight VERY quickly…but more importantly, safely too.

Ultimately, what the carb rotation system does is to take your body through a system of switching your carbs around on predefined days, so as to somehow "trick" your body temporarily to keep wanting to burn fat instead of getting used to the changes and storing it.

You can trick your body by switching things up for one day and keep your metabolism and fat burning in high gear. Increase your carbohydrate intake to 80% of normal (this is 400 grams for the referenced 200 pound male). This increase will fool your body and keep your metabolism high while also providing you with much needed energy at this point.

P.S.

Don't forget to increase protein. During your reduced carbohydrates you will need additional protein to keep your body from using your muscles as fuel. Follow the schedule below for protein intake to avoid this problem.

If you decide NOT to use this new carb rotation system, make sure (at the very least) that you :

* Eat six meals a day (to keep metabolism at peak level)

* Drink at least 64 ounces of water daily

* Exercise daily

However, if you truly want to know how to lose weight very quickly then the carb rotation diet at http://trustusreviews.com/carbrotation is easily your best bet by far. I personally guarantee it.

The other options are to attempt the celebrity style bland endurance for a few weeks, or to simply go flat out at the gym whilst eating regular foods.

I know which I would prefer, don't you?

Again, make sure you at least check out how easy it can be to lose weight very quickly, and more importantly safely too. Go and see for yourself right now at http://trustusreviews.com/carbrotation

Above all, good luck in your weight loss mission whatever you decide!
References :
http://trustusreviews.com/carbrotation