Weight Loss and Cutting Ultra-Processed Foods Drive Liver Fat Reduction in MASLD: JST| September 2026

Introduction:

Diet is central to MASLD management, but whether one dietary pattern is superior remains uncertain. This 6-month randomized trial compared a Mediterranean diet, low-carbohydrate high-protein diet, and standard nutritional advice, while examining the impact of weight loss and ultra-processed food (UPF) reduction.

Why was this study needed?

Mediterranean and low-carbohydrate diets are commonly recommended, but their benefits may largely reflect weight loss rather than diet composition. The independent contribution of reducing UPFs also remains poorly understood.

Study Design:

173 patients with MASLD and overweight or obesity were randomized to the three dietary strategies; 148 completed 6 months. Liver fat was assessed using controlled attenuation parameter (CAP).

Key Results:

There was no significant difference between diets in liver-fat improvement.

Instead, two factors independently predicted CAP reduction:

↓ BMI → ↓ liver fat

↓ UPF consumption → ↓ liver fat

All groups also improved weight, adiposity, metabolic parameters and overall dietary quality.

Why Are Ultra-Processed Foods Important?

UPFs are typically rich in added sugars, refined carbohydrates, saturated fats and energy, and are associated with insulin resistance, visceral adiposity, inflammation and hepatic lipogenesis.

Importantly, reducing UPF intake predicted improved steatosis irrespective of the assigned diet.

Clinical Impact:

The practical question may therefore shift from:

“Which MASLD diet is best?”

to:

“Which healthy diet can this patient sustain to lose weight and reduce ultra-processed foods?”

A Mediterranean diet remains an excellent option, but flexibility may improve long-term adherence.

A Practical MASLD Nutrition Message:

Sustainable calorie reduction → weight loss → fewer ultra-processed foods → more minimally processed foods → long-term adherence

Caution:

Liver fat was measured by CAP rather than MRI-PDFF or histology, and follow-up was only 6 months. The study does not establish whether UPF reduction independently improves MASH, fibrosis or long-term outcomes.

Bottom Line:

In MASLD, liver-fat improvement appears driven more by weight loss and reduced ultra-processed food intake than by a specific dietary pattern. The best diet may therefore be a healthy, sustainable diet the patient can actually follow.