Intermittent fasting bests standard diet in lowering liver fat content in MASLD, obesity
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Key takeaways:
- At 12 weeks, 72.2% of the intermittent calorie restriction group achieved at least 30% reduction in liver fat content vs. 44.4% in the standard of care group.
- This effect was greater among those with obesity.
An intermittent calorie restriction diet was “safe and more effective” in reducing hepatic steatosis at 12 weeks vs. a standard of care diet in metabolic dysfunction-associated steatotic liver disease, particularly among those with obesity.
“Intermittent calorie restriction involves alternating periods of energy restriction and regular energy intake and has been proposed as a dietary intervention for MASLD,” Han Ah Lee, of the department of internal medicine at Chung-Ang University, and colleagues wrote in Clinical Gastroenterology and Hepatology. “Previous studies have suggested potential benefits of intermittent calorie restriction diet, including weight loss, improvement in insulin resistance, reduced oxidative stress and decreased level of systemic inflammation. ... However, there are limitations in such studies.”
To assess the effects of intermittent calorie restriction, Lee and colleagues enrolled 72 patients with MASLD, who were stratified by BMI, and randomly assigned them 1:1 to an intermittent calorie restriction diet (median age, 47 years; 58.8% men) or standard of care diet (median age, 53 years; 36.4% men) for 12 weeks. All patients had an MRI-proton density fat fraction (PDFF) level of at least 8% at baseline, with mean liver fat content measurements of 16.6% and 14.9%, respectively.
Patients on the intermittent calorie restriction diet consumed up to 600 kcal per day on 2 nonconsecutive days of the week, with an intake limit of up to 2,500 kcal per day on the remaining 5 days. Those on the standard of care diet consumed 80% of standard calories (1,200-1,500 kcal/day for women and 1,500-1,800 kcal/day for men or a reduction of up to 1,000 kcal/day).
The primary outcome was the proportion of patients who achieved a relative liver fat content reduction of at least 30%.
According to results, 63 patients completed the study, 32 in the intermittent calorie restriction group and 31 in the standard of care group. At 12 weeks, a greater proportion of those in the intermittent calorie restriction group achieved the primary outcome (72.2% vs. 44.4%), a difference of 27.8 percentage points (95% CI, 3.3-49.8).
In addition, among patients with obesity, a higher proportion reached a relative liver fat content reduction of at least 30% with intermittent calorie restriction vs. standard of care (61.1% vs. 27.7%; difference = 33.4 percentage points; 95% CI, 3.9-66.7). Among patients without obesity, the changes were comparable between groups (83.3% vs. 61.1%; difference = 22.2 percentage points; 95% CI, –12 to 30.5).
The relative reduction in body weight also was similar between groups (–5.3% vs. –4.2%), although it was greater among those with obesity in the intermittent calorie restriction group (–5.5% vs. –2.9%).
“The 12-week intermittent calorie restriction diet was safe and more effective than the standard of care diet in reducing hepatic steatosis, particularly in patients with obesity and MASLD,” Lee and colleagues wrote. “These results support the recommendation of a 5:2 intermittent calorie restriction diet as a useful dietary strategy for patients with MASLD and provide a basis for further research.”
They continued: “In future studies, the effects of intermittent calorie restriction require additional validation in different settings, such as in patients with MASH and individuals with co-existing diabetes, and comparisons with other diet types.”
Perspective
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Katherine Patton, RD
While it is promising that patients can lose a significant amount of liver fat with an intermittent calorie restriction diet, I am concerned about the quality of the diet during the 5 days there is no restriction.
The reason MASLD can be hard to manage is because there are multiple metabolic risk factors that contribute to MASLD. These include elevated triglycerides, blood pressure, glucose and waist circumference, along with low HDL cholesterol, all of which need to be managed.
It is important for patients to recognize that sources of calories matter. While following a standard diet 5 days per week, it is ideal to follow a carbohydrate-controlled, protein-rich, moderate-fat eating pattern to control metabolic risk factors. At the same time, when following a calorie restriction diet 2 days per week, patients should be eating mostly protein to preserve muscle mass and lose fat.
It is also not surprising that the intermittent calorie restriction group lost more weight, because they had a greater calorie deficit compared with the standard of care group.
As the authors point out, this is a safe diet. Therefore, it would be worth replicating this diet with participants in the U.S. to see whether researchers obtain the same outcomes as with study participants from Korea.
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