Pneumonia is a term used to describe inflammation of the lungs. It is usually caused by a bacterial, viral or parasitic infection. Pneumonia often starts with symptoms similar to that of a cold and gradually worsens.

Puberty causes changes in the shape and feeling of your body. "Man boobs" on a 13-year-old boy may be an effect of having too much body fat, but they can also develop as a result of hormonal shifts occurring during puberty. This growth of breast tissue in a teenage guy is known as gynecomastia.

When it comes right down to it, weight loss is all about calories. Knowing the number of calories your body burns to perform daily functions, which is referred to as the basal metabolic rate, or BMR, can help you determine the number of calories you need to lose weight.

Overweight and obesity are serious health problems that affect over 17 percent of children and teens in the United States. Being an overweight teen girl can affect your self-image and self-esteem and cause social problems.

Childhood obesity has become one of the biggest health concerns in the United States, according to My Overweight Child. Genetics, a diet high in fat and sugar, overeating and living a sedentary lifestyle can all contribute to an overweight child.

An occasional diet soda in small amounts is probably safe for children, according to the Mayo Clinic. However, daily consumption of diet soda may be cause for concern.

You may be alarmed if you find small red bumps or pus-filled pimples on your child's scalp. There are a number of causes that can mimic acne pimples, and it is even possible that your child is starting to develop acne.

Almost one in three children are overweight or obese, according to the American Heart Association in 2010. In addition to developing increased risks for diabetes, high cholesterol and heart disease, obese children suffer from a variety of psychological and social problems.

According to the Centers for Disease Control and Prevention, as of 2008 as many as 19.8 percent of adolescents younger than 19 were considered obese.

Being overweight as a teenage girl can make school and personal life more challenging. If your teen has expressed a desire to lose weight, you can help her do it in a way that's safe and sustainable. She'll have to eat a healthy, reduced-calorie diet and increase her physical activity.

About 17 percent of children and adolescents ages 2 to 19 years are obese, reported the Journal of the American Medical Association in 2014.

A diet plan for overweight teens is more of a health and nutrition roadmap for life – quick fixes or fad diets will not maintain a teen’s weight loss. The term overweight is synonymous with impending health issues such as heart disease, diabetes and high blood pressure.