Liver

Fatty liver is rarer on healthy plant-based diets

By WhyStopHarmingAnimals.com

Fatty liver disease now affects a large share of adults, and with no drug treatment worth the name, diet is the treatment. The healthiest plant-based diets come with substantially lower odds of it[1][2], and in one older population the disease regressed in people eating a plant-based, high-fibre, low-fat diet[3].

Measured in the liver itself

Much of the older research estimated liver fat from blood work. A study of 3,900 US adults measured it directly by elastography instead (Nutrients, 2022)[1]. The healthiest plant-based diets came with 36% lower odds of fatty liver disease, even after accounting for body mass index[1]. An unweighted plant-based score, which counts any plant food the same whether it's lentils or soda, showed no association at all[1].

A US national survey of 18,345 adults found the same split (Clinical Nutrition, 2019). The top third of plant-based diet scores had 21% lower odds of fatty liver disease, with better liver enzymes across the board[2]. Scores built from unhealthy plant foods moved in the opposite direction on every measure[2].

Fatty liver that went away

In Rotterdam, researchers scanned 963 older adults twice, a median 4.4 years apart (European Journal of Epidemiology, 2020)[3]. Fatty liver regressed in 30% of those who had it at the first scan[3]. Of all the dietary patterns tested, adherence to a plant-based, high-fibre, low-fat pattern was the one that tracked with the regression[3].

Which foods matter

A pooled analysis of 24 studies across 11 food groups (British Journal of Nutrition, 2020)[4] linked red meat and soft drinks with higher odds of fatty liver disease, red meat by about 12%[4], and nuts with lower odds[4]. Whole grains, refined grains, fish, fruit, vegetables, eggs, dairy and legumes showed no significant effect either way[4]. Red meat and sugary drinks were the clearest harms[4], and nuts the clearest help[4].

Trial evidence from elsewhere fits. In a 16-week randomized trial of 244 people, a low-fat vegan diet cut liver fat by 34%[5], with no change in the control group[5] (JAMA Network Open, 2020).

The limits

The four fatty liver studies are observational, and the effect depends heavily on the quality of the diet[1][2]: a plant-based score that ignores quality shows nothing[1]. Fish, eggs and dairy showed no clear effect in the pooled food-group analysis[4]. The consistent signals are a lower risk on diets built around whole plant foods[1][2] and a higher one with red meat[4].