The effects of alcohol on body weight are dependent upon the timing and amount of alcohol consumption in relation to meals and on the presence or absence of organ damage, in particular alcoholic liver disease (Table 2). Whereas body weight is usually unaffected by moderate alcohol consumption, chronic alcoholics who drink daily while substituting alcohol for other dietary constituents lose weight due to the energy neutral effect of alcohol in the diet. Moderate drinkers on weight loss regimens are less likely to lose weight while consuming alcohol with their meals since one effect of alcohol is to decrease restraint over food intake. At the same time, those who consume alcohol with high-fat meals are more likely to gain weight due to an acute effect of alcohol on reducing the oxidation of fat at the same time as it promotes its storage.
The presence of alcoholic liver disease results in significant changes in body composition and energy balance. Although fatty liver is fully reversible, progression to alcoholic hepatitis can have profound effects on nutritional status. According to large
Table 2 Effects of alcohol on body weight
Increase weight Heavy drinking
Substitution of carbohydrate by alcohol; more likely in women Decreased dietary restraint
Substitution of nonalcohol calories by alcohol calories, which are 'wasted' during metabolism Alcohol metabolism decreases lipid metabolism, promotes fat storage multicenter studies, alcoholic hepatitis patients demonstrate universal evidence for protein calorie malnutrition, according to the physical findings of muscle wasting and edema, low levels of serum albumin and other visceral proteins, and decreased cell-mediated immunity, whereas their 6-month mortality is related in part to the severity of malnutrition. Anorexia is a major cause of weight loss in alcoholic liver disease, and may be caused by increased circulating levels of leptin. Furthermore, active alcoholic hepatitis contributes to increased resting energy expenditure as another cause of weight loss. On the other hand, resting energy expenditure is normal in stable alcoholic cirrhotics who are also typically underweight or malnourished in part due to preferential metabolism of endogenous fat stores. At the same time, the digestion of dietary fat is decreased in cirrhotic patients due to diminished secretion of bile salts and pancreatic enzymes.
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