Energy expenditure in chronic alcohol abuse

Background: In healthy subjects, alcohol decreases lipid oxidation favouring fat deposition. However, individuals who chronically abuse alcohol are not obese. To investigate this paradox, we measured energy expenditure (EE) and fuel utilization in chronic alcohol abusers in relation to their drinking behaviour. Methods: Resting and postprandial EE and nonprotein respiratory quotient (NPRQ) were measured using indirect calorimetry, in 36 alcohol abusers [mean (± SE) age 42 ± 2 years; weight 67 ± 2 kg; 21 with steatosis, eight with hepatitis; seven with cirrhosis] and in 36 gender-, age- and weight-matched healthy controls. Alcoholic patients were re-evaluated either after 14 days (n= 14) or on days 2, 4, 6, 8, 14 and 42 (n= 6) after abstinence. Results: When alcoholics were compared to healthy controls, mean energy intake was greater, 15 ± 1 MJ day^-1 (38 ± 2% from alcohol) cf. 9 ± 1 MJ day^-1 (P < 0.001), resting EE increased, 82 ± 2 cf. 65 ± 2 W (P < 0.001) and NPRQ decreased, 0.75 ± 0.02 cf. 0.82 ± 0.01 (P < 0.001). The postprandial increases in EE and NPRQ were of similar magnitude in both groups. Abstinence from alcohol for 14 days was accompanied by reduced energy intake, 16 ± 1 cf. 11 ± 1 MJ day^-1 (P < 0.005) and decreased resting EE, 84 ± 5 cf. 73 ± 4 W (P < 0.05). The decrease in resting EE consistently occurred 4 days after abstinence from alcohol. Conclusions: Chronic alcohol abuse is associated with energy wasting and inhibition of adipose tissue accumulation. This may explain why alcoholics are not obese despite high total energy intakes.