A hypocaloric protein-rich diet before metabolic surgery improves liver function in patients with obesity and diabetes : A secondary analysis of a randomized clinical trial.

Purpose: Obesity and type 2 diabetes (T2DM) are major risk factors for hepatic steatosis. Diet or bariatric surgery can reduce liver volume, fat content, and inflammation. However, little is known about their effects on liver function, as evaluated here using the LiMAx test.

Methods: In the MetaSurg study (RCT on the effects of different Roux-en-Y gastric bypass (RYGB) limb lengths on diabetes remission in patients with BMI ≥ 27 to ≤ 60 kg/m and T2DM; trial registration: DRKS00007810, German Clinical Trials Register Freiburg), 24 consecutive patients underwent liver function (LiMAx) and imaging assessments (MRI, transient elastography; TE) before and after diet and surgery. Two weeks before surgery, the patients received a hypocaloric protein-rich diet.

Results: Nine of 18 patients had a pathologic LiMAx value (≤ 315 µg/kg/h) at baseline. After two weeks of diet, LiMAx values improved (p = 0.01, paired t test, n = 15). LiMAx values further recovered six months after RYGB (p = 0.01, paired t test, n = 15), which was accompanied by decreased liver volumes (p = 0.005, paired t test, n = 10), proton density fat fraction (p = 0.003, paired t test, n = 12), and TE measurements (p = 0.032, paired t test, n = 14). The need for medical diabetes treatment decreased from 100 to 35%.

Conclusion: Liver function improved after a two-week hypocaloric protein-rich diet and metabolic surgery in patients with obesity and T2DM. These data suggest that a two-week diet for this group of patients prior to abdominal surgery could improve a presumably impaired liver function.