When the body is starved of nutrients it seeks to conserve what reserves of energy it has in order to protect vital tissues. This is why as you continue to restrict your eating the amount of weight you lose will lessen over time. Basically the boy adapts to “famine conditions”, seeking ways to burn calories at a slower rate and so to preserve your health. As your metabolism rate slows, as does your growth rate. In pre-pubescent women, for example, with anorexia puberty is delayed.
The state of starvation causes feelings of fatigue and weakness as your body seeks to make you reduce physical activity and therefore conserve energy. In many cases, however, the psychological urge to increase activity and thus speed up weight loss will over-ride these physical feelings. As you seek to lose more and more weight your body is actually pitching against you: hence that feeling common in anorexia of being at war with your body. Ultimately is starvation continues the regulatory mechanisms of the body will be over-ridden. Epileptic fits are not uncommon amongst people with anorexia, usually occurring in the context of disrupted internal environment.
The skin may become dry and crusted due to starvation. Also a fine layer of hair, called lanugo, may grow all over the body a bit like the “fuzz” on the skin of a peach. The skin may also develop an orange tinge, particularly on the pales of hands and soles of feet, this is caused by high levels of carotene in the blood due to the liver becoming unable to break it down.
Myopathy (muscle wasting and weakness)
When in a state of starvation the body turns to reserves within itself for energy, this included metabolising muscle. In extreme cases this includes heart muscle! This muscle wastage results in a drawn and haggard appearance.
The less muscle you have the slower you will burn calories. Also, as the muscles are not getting all the nutrients they need they work even less well than would be predicted from wastage alone. Signs of severe myopathy include difficultly climbing stairs, a flat footed method of walking an even an inability to stand from a squatting position without help.
Lower back pain
This can be caused due to bone thinning (osteoporosis) or, more usually, by the spinal column not having enough muscle support.
In advanced stages of starvation, shrinkage of the brain may occur.
In cases of severe starvation, the heart weakens and its efficiency at pumping blood is greatly reduced. Blood pressure becomes lower, which results in dizziness and fainting. In extreme cases cardiomyopathy can develop: this is characterised by the failure of the heart muscle to function efficiently, and can result in chest pains and palpitations.
These can be effected by the low blood pressure, making them less efficient and causing slow damage. Also dehydration and low levels of potassium can cause serious damage.
The immune system
This is greatly impaired by starvation.
The reproductive system
Starvation impairs fertility by causing the uterus and ovaries to shrink. Amenorrhea (cessation of menstruation) is an inevitable consequence.