Effects of Dietary Interventions on Liver Volume in Humans

Objective: To compare effects of similar weight loss induced either by a short-term low-carbohydrate or by a long-term hypocaloric diet, and to determine effects of high carbohydrate overfeeding on liver total, lean, and fat volumes. Methods: Liver total, lean, and fat volumes were measured before and after (i) a 6-day low-carbohydrate diet (n=17), (ii) a 7-month standard hypocaloric diet (n=26), and (iii) a 3-week high-carbohydrate diet (n=17), by combining magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (H-1-MRS) techniques. Results: At baseline, three groups were comparable with respect to age, body mass index, liver volumes and the liver fat content. Body weight decreased similarly by the short-term and long-term hypocaloric diets. Liver total volume decreased significantly more during the short-term low-carbohydrate (-22 +/- 2%) than the long-term (-7 +/- 2%) hypocaloric diet (P < 0.001). This was due to a greater decrease in liver lean volume in the short-term (-20 +/- 2%) than the long-term (-4 +/- 2%) weight loss group (P < 0.001). Decreases in liver fat were comparable. Liver volume increased by 9 +/- 3% due to overfeeding (P < 0.02 for before vs. after). Conclusions: These data support the use of a short-term low-carbohydrate diet whenever a reduction in liver volume is desirable. Overeating carbohydrate is harmful because it increases liver volume.