Metabolism is the process your body uses to make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system (enzymes) break the food parts down into sugars and acids, your body's fuel. Your body can use this fuel right away, or it can store the energy in your body tissues. If you have a metabolic disorder, something goes wrong with this process.

Mitochondrial diseases are a group of metabolic disorders. Mitochondria are small structures that produce energy in almost all of your cells. They make it by combining oxygen with the fuel molecules (sugars and fats) that come from your food. When the mitochondria are defective, the cells do not have enough energy. The unused oxygen and fuel molecules build up in the cells and cause damage.

The symptoms of mitochondrial disease can vary. It depends on how many mitochondria are defective, and where they are in the body. Sometimes only one organ, tissue, or cell type is affected. But often the problem affects many of them. Muscle and nerve cells have especially high energy needs, so muscular and neurological problems are common. The diseases range from mild to severe. Some types can be fatal.

Genetic mutations cause these diseases. They usually happen before age 20, and some are more common in infants. There are no cures for these diseases, but treatments may help with symptoms and slow down the disease. They may include physical therapy, vitamins and supplements, special diets, and medicines.

Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even paralysis.

Causes of muscle disorders include:

• Injury or overuse, such as sprains or strains, cramps or tendinitis
• A genetic disorder, such as muscular dystrophy
• Some cancers
• Inflammation, such as myositis
• Diseases of nerves that affect muscles
• Infections
• Certain medicines

Sometimes the cause of muscle disorders is unknown.

Any part of your neck - muscles, bones, joints, tendons, ligaments, or nerves - can cause neck problems. Neck pain is very common. Pain may also come from your shoulder, jaw, head, or upper arms.

Muscle strain or tension often causes neck pain. The problem is usually overuse, such as from sitting at a computer for too long. Sometimes you can strain your neck muscles from sleeping in an awkward position or overdoing it during exercise. Falls or accidents, including car accidents, are another common cause of neck pain. Whiplash, a soft tissue injury to the neck, is also called neck sprain or strain.

Treatment depends on the cause, but may include applying ice, taking pain relievers, getting physical therapy or wearing a cervical collar. You rarely need surgery.

Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the first month of pregnancy, often before a woman even knows that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In spina bifida, the fetal spinal column doesn't close completely. There is usually nerve damage that causes at least some paralysis of the legs. In anencephaly, most of the brain and skull do not develop. Babies with anencephaly are usually either stillborn or die shortly after birth. Another type of defect, Chiari malformation, causes the brain tissue to extend into the spinal canal.

The exact causes of neural tube defects aren't known. You're at greater risk of having an infant with a neural tube defect if you:

• Have obesity
• Have poorly controlled diabetes
• Take certain antiseizure medicines

Getting enough folic acid, a type of B vitamin, before and during pregnancy prevents most neural tube defects.

Neural tube defects are usually diagnosed before the infant is born, through lab or imaging tests. There is no cure for neural tube defects. The nerve damage and loss of function that are present at birth are usually permanent. However, a variety of treatments can sometimes prevent further damage and help with complications.

NIH: National Institute of Child Health and Human Development

Obesity is a disease that means having too much body fat. It is different from being overweight, which means weighing too much. Both terms mean that your weight is greater than what's considered healthy for your height.

Body Mass Index (BMI) measures how much you weigh compared to how tall you are. An adult who has a BMI of 30 or more is considered to have obesity. Severe obesity is having a BMI of 40 or higher. Obesity increases your risk for many other diseases and health problems, especially if the extra body fat is carried around the waist.

Obesity happens over time from taking in more calories (through food and drinks) than used up from physical activity and daily living. Your body stores the extra calories as fat. The right balance between calories and activity is different for everyone.

There are many different factors that can affect your body weight. Certain medicines or medical conditions may affect your weight. Other factors include your:

• Genetic makeup
• Eating habits
• Sex
• Race or ethnicity
• Physical activity level

To find out if you have obesity, your health care provider may:

• Ask about your health history, which may include reviewing your weight history, weight-loss efforts, and how physically active you are.
• Do a physical exam, which may include checking your height, weight, and vital signs, as well as listening to your heart and lungs.
• Order blood tests or other imaging tests, which may include checking any known health problems, as well as for other weight-related diseases and health conditions.
• Calculate your BMI, to check your risk for certain diseases. The higher your BMI, the higher your risk. BMI does not distinguish between fat, muscle, and bone mass. It may also overestimate body fat in athletes or those with a muscular build, or underestimate body fat in older persons, or others who have lost muscle.
• Check your waist size, since a large waistline, with more body fat around your abdomen (belly) rather than your hips, increases your risk for weight-related health problems.

Having a larger body size can make your heart work harder, put extra pressure on your joints, and may increase your risk for many health conditions, including:

• Type 2 diabetes.
• Heart disease.
• High blood pressure.
• Stroke.
• Metabolic syndrome.
• Osteoarthritis.
• Sleep apnea.
• Pregnancy problems.
• Fertility problems.
• Some cancers.

If you have obesity, losing even 5 to 10% of your weight can delay or prevent some of these diseases. For example, that means losing 10 to 20 pounds if you weigh 200 pounds.

Treatment plans for obesity may depend on your overall weight, other health conditions, and your willingness to participate in a weight-loss plan.

Your provider can tell you what a healthy weight is for you, help you set goals, and give you tips on how to lose weight. They may refer you to other providers that specialize in nutrition or weight loss to help you make realistic goals and provide support.

Possible treatments may include:

• Dietary changes and exercise goals to help you learn how to adopt healthy nutrition, exercise, and lifestyle changes to lose weight safely and keep it off long term.
• Counseling or support groups can give you encouragement and help you understand what's behind weight changes.
• Weight-loss medicines to treat obesity.
• Weight loss procedures or surgery if you have severe obesity or serious obesity-related health problems and have not been able to lose enough weight.

A healthy lifestyle that includes healthy eating patterns and regular physical activity can help you lose weight and lower your chance of developing complications related to obesity.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases