Numerous conditions can cause rapid weight loss in teenagers. According to MayoClinic.com, obesity is a common health problem among American teens. The quest for appearances and a better body drive some teenagers to adopt unhealthy eating habits.

If you want to lose weight quickly and are unwilling to alter your diet, you should do some form of at least moderate physical activity every day of the week. You will generally lose weight when you eat significantly fewer calories than normal, burn significantly more calories through exercise than normal or both.

The thick layers of cellulose on the cell walls of raw carrots prevent your body from digesting and fully absorbing the vitamins and minerals in these vegetables. By juicing carrots, you break down these cell walls and increase the concentration of carrots that you can consume.

Silicon, a naturally occurring element, is pervasive in the environment and the second-most common element in the Earth's outer crust. This element is beneficial for a variety of health functions. Most silicon exists in a form that is unabsorbable.

Your body consists of fat and all the rest: its fat-free components. If you are overweight, improving your body composition involves lowering your percentage of body fat.

A severe deficiency of dietary protein causes kwashiorkor. Many children in developing countries, who are given a high-carbohydrate and low-protein diet after they are weaned from breast milk, develop kwashiorkor.

The original Stacker 3 was a popular weight loss supplement that contained ephedra. In 2004, the Food and Drug Administration banned ephedra in weight loss products in the United States. Manufacturers of ephedra-based supplements including Stacker 3 had to change product formulations to comply with the FDA ban.

To lose weight, you need to burn more calories with physical activity than you take in by eating and drinking. The total number of calories you consume minus the total number of calories burned is your net calories. The lower your net calories are every day, the more weight you will lose.

One pound of fat contains 3,500 calories. To lose this the number of calories you burn each day must outnumber the number of calories you consume through food. The American Academy of Family Physicians says it is safe, healthy and sustainable to lose one to two pounds per week regardless of your starting weight.

Nausea can be brought on by food poisoning, pregnancy or illness. When you feel nauseous, eating certain foods can prevent you from vomiting. If you don't feel like eating, start with fluids and move to solid foods as you begin to feel better.

While there is no cornflake diet, ready-to-eat cereal works as a convenient meal option for those trying to lose weight, and it can work as a diet-friendly meal in place of higher-calorie options.

Dining out is a challenge for anyone on a weight loss plan and the Weight Watchers program is no exception. Though a few restaurants, such as Applebees, print Weight Watchers points right on the menu, most restaurants don't.