Researchers compared 121 people with fatty liver disease to 119 healthy people to understand how different types of carbohydrates affect liver health. They found that people who ate higher-quality carbohydrates—like whole grains instead of refined carbs—had significantly lower chances of developing fatty liver disease. The study also showed that better carb choices were linked to healthier blood sugar levels and less liver damage. These findings suggest that the type of carbohydrates you eat matters more than just the amount, and choosing quality carbs could be an important way to prevent this increasingly common liver condition.

The Quick Take

  • What they studied: Whether eating better-quality carbohydrates and eating fewer carbs overall could help prevent or reduce fatty liver disease (a condition where fat builds up in the liver)
  • Who participated: 240 adults in total: 121 people who had been diagnosed with fatty liver disease and 119 healthy people without the condition. The group with fatty liver disease was slightly older and heavier on average.
  • Key finding: People who ate the highest quality carbohydrates had about 78% lower odds of having fatty liver disease compared to those who ate lower-quality carbs. This strong connection remained even after accounting for other health factors.
  • What it means for you: Choosing whole grains, beans, and other high-quality carbs instead of white bread, sugary foods, and processed snacks may help protect your liver. However, this is one study, so talk to your doctor before making major diet changes, especially if you have liver concerns.

The Research Details

This was a case-control study, which is like comparing two groups of people—one with a health condition and one without—to find differences in their habits or diet. Researchers asked 240 adults detailed questions about everything they ate using a food survey with 168 different food items. They then calculated two scores for each person: one measuring how much carbohydrate they ate, and another measuring how good the quality of those carbs was (based on things like fiber content and how quickly they raise blood sugar). The researchers also measured blood markers like liver enzymes and blood sugar levels to see how these related to carb quality.

The study was designed to look backward in time—researchers identified people who already had fatty liver disease and compared their eating habits to healthy people. This type of study is useful for finding connections between diet and disease, but it can’t prove that one directly causes the other.

Understanding which types of carbohydrates protect against fatty liver disease is important because this condition is becoming more common worldwide and can lead to serious liver problems. By identifying specific dietary factors that help prevent it, doctors and nutritionists can give people practical advice about what to eat. This study goes beyond just saying ’eat fewer carbs’ and instead focuses on ’eat better carbs,’ which is more helpful for real-world eating.

This study has several strengths: it used a detailed, validated food survey that’s been tested for accuracy, it measured actual blood markers to confirm liver health, and it adjusted for other factors that could affect results (like age and weight). However, because it’s a case-control study, it can’t prove carb quality causes better liver health—only that they’re connected. The sample size of 240 people is moderate, which is reasonable but not huge. The study was published in a peer-reviewed journal, meaning other experts reviewed it before publication.

What the Results Show

The main finding was striking: people who ate the highest quality carbohydrates had about 76% lower risk of fatty liver disease (the odds ratio was 0.22, meaning their risk was less than one-quarter that of people eating lower-quality carbs). This strong protective effect remained even after researchers adjusted for other factors like age, weight, and socioeconomic status.

People who ate fewer carbs overall also showed benefits, with about 70% lower odds of fatty liver disease in the highest group. However, the carbohydrate quality effect was stronger and more consistent in the final analysis.

When researchers looked at blood markers, they found that for every one-point increase in the carbohydrate quality score, people had lower liver enzyme levels (ALT), lower blood sugar levels, and higher antioxidant capacity (which means better protection against cell damage). These are all signs of better liver and metabolic health.

The study also found that people with fatty liver disease had several other health differences compared to the healthy group: they were slightly older (38 vs. 36 years), significantly heavier (BMI of 28.6 vs. 23.2), had higher fasting blood sugar (114 vs. 98 mg/dL), and had elevated liver enzymes. These differences suggest that fatty liver disease is connected to weight, blood sugar control, and overall metabolic health—areas where carbohydrate quality may also play a role.

This research supports and builds on previous studies showing that carbohydrate quality matters for metabolic health. Earlier research has shown that whole grains and high-fiber carbs are better for blood sugar control and weight management than refined carbs. This study extends that knowledge specifically to fatty liver disease, which is a newer area of research. The findings align with the general nutrition science consensus that not all carbohydrates affect the body the same way.

This study has several important limitations to consider. First, because it’s a case-control study, we can’t be certain that eating better carbs prevents fatty liver disease—we only know they’re connected. It’s possible that people with fatty liver disease changed their eating habits after diagnosis, which could affect the results. Second, the study relied on people remembering what they ate, which can be inaccurate. Third, the sample size of 240 people is relatively small, so results might not apply to everyone. Finally, the study doesn’t tell us exactly which carbs are ‘best’—just that higher quality scores are associated with better outcomes.

The Bottom Line

Based on this research, consider eating more whole grains, beans, legumes, vegetables, and fruits instead of white bread, sugary snacks, and processed foods. These higher-quality carbs appear to protect liver health. However, this is one study, so consider it as supporting evidence rather than definitive proof. If you have fatty liver disease or are concerned about liver health, talk to your doctor or a registered dietitian before making major diet changes. Confidence level: Moderate—the findings are strong but based on one case-control study.

This research is most relevant for people who have fatty liver disease, are overweight, have high blood sugar, or have a family history of liver disease. It’s also useful for anyone interested in preventing metabolic diseases. However, if you have severe liver disease or other serious health conditions, you should work with your doctor on dietary changes rather than making them on your own.

Improvements in blood sugar and liver enzyme levels may appear within weeks to months of changing your carbohydrate choices, but preventing fatty liver disease development is a longer-term benefit that may take several months to a year to become apparent.

Want to Apply This Research?

  • Track the ‘quality’ of carbohydrates eaten daily by logging whole grains, legumes, and high-fiber foods separately from refined carbs and sugary foods. Aim for a ratio of 70% high-quality carbs to 30% or less refined carbs.
  • Replace one refined carb choice per day with a whole grain or legume option—for example, swap white bread for whole wheat bread at lunch, or add beans to dinner instead of having only rice.
  • Weekly review of carb quality ratio and monthly check-ins on energy levels, digestion, and any available blood work (like fasting blood sugar if monitored by a doctor) to see if changes are having positive effects.

This research suggests an association between carbohydrate quality and fatty liver disease risk, but it does not prove cause and effect. This information is for educational purposes and should not replace professional medical advice. If you have fatty liver disease, elevated liver enzymes, or concerns about your liver health, consult with your healthcare provider or a registered dietitian before making significant dietary changes. Individual results may vary based on genetics, overall diet, lifestyle, and other health factors.