Bulimia nervosa and binge-eating have a number of physical complications. These arise either as a direct result of binge-eating or as a consequence of the measures taken to compensate for overeating.
Binges usually produce a sense of fullness and bloatedness; sometimes this is so extreme as to cause profound abdominal discomfort and, occasionally, acute pain in the abdomen. The fullness frequently leads to breathlessness caused by the distended stomach pressing up against the diaphragm and thereby interfering with breathing. In rare cases, the stomach wall can be damaged and even tear. This is a serious medical emergency.
General digestive problems are common among people who binge. These include stomach cramps, flatulence, constipation and diarrhoea.
Dieting can have adverse physical effects. It has been suggested that repeatedly going on and off diets (so-called ‘yo-yo dieting’) can actually cause people to gain weight over time. What seems to happen is that, when someone is dieting and losing weight, their body becomes metabolically efficient and, as a consequence, they can function on a relatively low number of calories without losing weight. Then, when they resume eating normally (or begin overeating) this metabolic efficiency persists and they gain weight rapidly, overshooting the weight at which they started dieting. This would explain why people who go on and off diets tend gradually to become heavier and heavier.
Both a low carbohydrate diet and a low body weight can have a significant impact on hormonal functioning. Menstrual periods may become irregular or stop altogether. This is because normal menstruation depends on the body maintaining a certain proportion of fat (around 20 per cent). The dieting practised by people with bulimia nervosa often reduces the proportion of body fat to below this critical level. It has also been found that a woman who is only 5–10 per cent under her ideal body weight may undergo subtle alterations in the menstrual cycle which can compromise fertility.
As noted above, vomiting is not nearly as effective a means of compensating for overeating as people tend to believe. It also has a number of adverse physical effects, some of which can be medically serious.
First, repeated vomiting leads to an erosion of the dental enamel, mainly on the inner surface of the teeth. This is caused by the teeth repeatedly being exposed to acid from the stomach. Many people brush their teeth vigorously after vomiting to get rid of the smell; this actually damages the teeth further, because the presence of the acid in the mouth means that brushing the teeth effectively scours them. Using a mouth wash, rather than brushing, would reduce the potential damage somewhat. However, the damage caused to the teeth by repeated vomiting is irreversible.
Second, vomiting causes the salivary glands below the jaw to swell. This is painless, but it does make the face look rather puffy; this is particularly distressing to someone with bulimia nervosa, who is apt to interpret the swelling as a sign of weight gain and may well respond with further vomiting.
Third, repeated vomiting often causes damage to the throat. This is because most people who vomit need to induce the gag reflex by sticking something down their throat. Gagging in this way is sometimes difficult and some people have to use considerable force. The back of the throat is frequently injured in this process. Sometimes it bleeds and the injuries often become infected. People who vomit frequently commonly develop a hoarseness in their voice.
Very rarely, violent vomiting causes a tear in the oesophagus (the tube linking the mouth to the stomach). If the oesophagus ruptures, it is a medical emergency. Vomiting repeatedly for many years can also lead to a weakening of the oesophageal sphincter (the set of muscles at the top of the stomach). The result of this is that there is nothing to prevent the contents of the stomach from returning up the oesophagus into the mouth (so-called gastric reflux). This can be uncomfortable, distressing and embarrassing.
The effects of vomiting on the body’s physiology can be serious, especially for those who flush their stomachs by repeatedly vomiting, drinking and vomiting again until they are satisfied that their stomach is empty of food. This process upsets the balance of body fluids and body salts (electrolytes). The abnormality of most concern is low potassium (hypokalemia) because it can result in serious heartbeat irregularities. Almost half of those with bulimia nervosa who come for treatment have some fluid or electrolyte abnormality, but most of these will not show any symptoms. Electrolyte disturbance is reversible and the abnormalities disappear once vomiting stops.
As noted above, laxatives and diuretics, like vomiting, are ineffective as well as a dangerous way of attempting to control weight. Laxatives have very little impact on calorie absorption, and diuretics have none at all. Misuse of laxatives causes several complications. As already mentioned, people may become dependent on them and need to take larger and larger doses to achieve the desired effect. Also, stopping taking laxatives can be difficult, because the shock to a body that has become used to them leads to ‘rebound’ constipation and water retention. The latter effect can also arise when people stop taking diuretics.
As with vomiting, laxative and diuretic misuse can cause a variety of fluid and electrolyte abnormalities. People who both vomit and take laxatives are especially at risk of such complications. Some laxatives, when taken in large doses, can cause damage to the gut wall. However, the other physical consequences of laxative and diuretic misuse disappear rapidly once the person stops taking them.
There is no evidence that appetite suppressants have a significant impact on binge-eating. They also have certain complications; for example, they can cause agitation or depression. They cannot be recommended for people who binge.
Most people who come for treatment of bulimia nervosa or binge-eating have been overeating and vomiting for some years. By this time many will have suffered some damage to their teeth. However, they are most unlikely to have caused themselves any other permanent physical harm. When they restore their eating habits to normal their bodies soon return to a healthy state.