If anorexia nervosa is not treated, the condition can lead to severe health problems.

If treatment is not improving your symptoms, or you start to get worse, your healthcare professional may consider changing your treatment. This may include treatment in hospital if your health is seriously at risk.

It is quite common for anorexia to return after treatment. For example:

• if someone's weight starts to fall again, or
• after having a baby, when a woman tries to lose the weight she gained during pregnancy

Other health problems

If someone has anorexia for a long time, it can lead to severe complications and health problems that can sometimes be permanent, such as damaged bones.

People with anorexia have an increased risk of:

• poor circulation and cardiovascular problems
• heart conditions, such as coronary heart disease and irregular heartbeat (arrhythmia)

Sometimes, anorexia can lead to another eating disorder called bulimia nervosa, where the person binge eats, then immediately makes themselves sick or uses laxatives to rid their body of the food.

Anorexia can cause an imbalance of minerals in the blood, such as potassium, calcium and sodium.  These minerals play an important part in keeping you healthy. For example, a common complication is a low level of potassium (hypokalaemia), which can cause:

• tiredness
• weakness
• dehydration
• kidney damage
• fits
• irregular heartbeat (arrhythmia)

Low levels of calcium can cause muscles to contract tightly and painfully (spasms). Lack of calcium and vitamin D can cause bone damage.

Lack of sodium (hyponatraemia) can cause people to become confused. In severe cases, it can cause fits (when your body jerks uncontrollably because of your muscles contracting).

Other complications of anorexia can include:

• low blood pressure (hypotension)
• anaemia
• dental problems, such as tooth decay caused by regular vomiting (stomach acid affects the enamel on the teeth)
• low blood sugar levels (hypoglycaemia)
• acute kidney (renal) failure
• liver damage
• heart failure
• osteoporosis (fragile bones) and loss of muscle strength, particularly in women and girls
• loss of sex drive (libido) and impotency in men

Misuse of laxatives can permanently damage the bowels and cause permanent constipation.

Anorexia and pregnancy

If you have anorexia and are pregnant, your GP or midwife will monitor your health closely during your pregnancy and after your baby is born. You may need extra health checks as part of your antenatal and postnatal care.

Anorexia during pregnancy can increase the risk of complications, such as

• miscarriage
• giving birth early (premature birth)
• a low-birthweight baby
• needing a Caesarean section

You are also likely to need extra care and support during pregnancy if you have previously had anorexia and recovered from it.

Anorexia and other health conditions

If you have anorexia and another health condition, you will need to take extra care of your health. For example:

• If you have diabetes, you will need regular health checks to help avoid problems with your eyes or other serious complications. This is particularly important if you have type 1 diabetes.
• If you have a bone condition, such as osteoporosis, your GP will probably advise you to avoid any physical activities that may lead to falls. 

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Dehydration

Dehydration is an excessive loss of fluids and minerals from the body.

Heart

The heart is a muscular organ that pumps blood around the body.