The effect of a two-week low glycaemic index, higher fibre diet versus high glycaemic index diet on body composition, ectopic lipids, inflammatory biomarkers, gastrointestinal hormones and gut microbiota in metabolic dysfunction-associated steatotic liver disease (MASLD): A pilot randomized cross-over study.

Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD) is a global health concern. Low glycaemic index (LGI) diets, which tend to be naturally higher in dietary fibre, may reduce liver fat, blood glucose, and gut microbiota imbalance arresting MASLD progression. We hypothesized that in patients with MASLD, an LGI diet, meeting estimated energy requirements, would reduce liver fat more than a high GI (HGI) diet, despite matched energy (isoenergetic) and macronutrient content. To test this, a 2 × 2 randomized cross-over trial was undertaken involving 7 participants with MASLD randomised (1:1 ratio) to a 2-week either high GI (HGI) or LGI diet followed by a 4-week wash-out period and then the opposite diet. The impact of the LGI diet on liver fat content, measured using Magnetic Resonance Spectroscopy (1H-MRS) liver-related blood biomarkers, appetite (using subjective visual analogue scales) and gut microbiome composition was identified. Relative liver fat fraction was markedly reduced following the LGI diet (8.57%).Observations in the LGI group coincided with changes in blood glycaemic biomarkers, including a significant reduction in HOMA-IR (-1.78, p = 0.043). Additionally, the LGI diet resulted in significant reductions in body weight (-1.2 kg, p = 0.018) and body mass index (-0.38 kg/m2, p = 0.017), as well as increased pre-meal appetite scores during the middle of the diet period and decreased interleukin 6; IL-6 (-0.9 pg/mL) and glucagon (-13.7 pg/mL) levels (all p < 0.05). In agreement with previous work in healthy participants, this study suggests that LGI diets reduce liver fat in patients with MASLD and may be an important factor in preventative care. REGISTRATION: This trial was registered on the website of ClinicalTrials.gov, number NCT04415632.