Gastroenterologist says fatty liver disease isn’t only linked to weight, explains how even lean people may be at risk

Genetic and environmental influences

“Understanding the impact of genetics and environmental factors on non-alcoholic fatty liver disease (NAFLD) is crucial, particularly for lean individuals. The interplay of genetic predispositions and lifestyle choices can create a perfect storm for the development of fatty liver disease,” Dr Aasima Boxwalla, Associate Consultant in Surgical Gastroenterology at Manipal Hospital, tells Health Shots.

What is fatty liver disease?

Fatty liver disease encompasses a spectrum of liver disorders, including:

• Fatty liver: Accumulation of fat in liver cells.
• Steatohepatitis: Inflammation caused by fat buildup.
• Cirrhosis: Scarring of the liver, often severe.
• Liver failure: The Liver’s inability to function adequately.
• Hepatocellular cancer: A type of liver cancer.

Causes of fatty liver disease

One of the most significant theories explaining fatty liver disease is insulin resistance. It occurs when the body fails to respond effectively to insulin, resulting in impaired glycogen synthesis. As a result, carbohydrates consumed are converted into fats that accumulate in the liver, according to the journal Nutrition.

Additionally, other contributing factors include:

• Imbalance of energy intake and metabolic needs: Excess calories, particularly from unhealthy foods, can lead to fat accumulation.
• Systemic inflammation: Chronic inflammation can exacerbate liver damage and fat storage.

Body mass index (BMI): The weight factor

While increased body mass index (BMI) is often associated with a higher risk of developing fatty liver disease, it is crucial to note that fatty liver can also affect individuals with a low BMI. In fact, around 20% of those with fatty liver disease are classified as lean, as per the journal Biomedicines.

This underscores significant insights into how we view health and weight:

• BMI limitations: BMI does not account for ethnic and gender differences, nor does it account for the distribution of body fat.
• Insulin resistance in lean individuals: Studies published in Human Nutrition & Metabolism have shown that lean individuals with higher visceral fat (fat stored around organs) may experience significant liver fat accumulation, increased insulin resistance, and higher triglyceride levels.

A recent study published in the Journal of Gastroenterology and Hepatology, involving 250 lean individuals (BMI < 23 kg/m²), highlighted this connection. Researchers found that higher visceral fat was associated with greater liver fat on biopsy. This evidence suggests that metabolic dysfunction, rather than body weight alone, plays a significant role in the development of fatty liver disease.

Dietary choices

When it comes to managing fatty liver disease, dietary modifications and exercise have proven essential. However, recent studies indicate that simply reducing caloric intake or focusing on weight loss may not be the most effective strategy. Instead, the quality of the diet can have a substantial impact, according to the journal PLOS One.

Key dietary recommendations

For individuals with fatty liver disease, incorporating the following dietary practices can make a difference:

• Increase protein and healthy fats: Focus on foods rich in protein and omega-3 fatty acids.
• Emphasise plant-based foods: Incorporate vegetables, fruits, and unrefined grains into your diet.
• Mind the carbs: Opt for low-glycemic-index carbohydrates and reduce refined sugar intake.
• Focus on healthy fats: Aim for higher proportions of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) while minimising saturated fats.
• Regular protein sources include fish, legumes, eggs, and poultry, which should be consumed at least once a week.
• Healthy cooking oils: Add olive oil to your daily meals.

Even without weight loss, implementing a nutrient-rich diet can enhance metabolic health. Over the past six months, numerous studies published in the Journal of Clinical and Experimental Hepatology have demonstrated significant improvements in liver function markers, including transaminases and liver stiffness measurements.

Exercise

Both aerobic and resistance training play vital roles in reducing liver fat and improving metabolic health, as reported in the journal Gut and Liver.

Regular exercise may help to:

• Improve insulin sensitivity: Regular fitness routines help the body respond more effectively to insulin, leading to improved glucose control.
• Enhance fat oxidation: Exercise helps the body mobilise and use fat effectively for energy, reducing accumulation in the liver.
• Support overall health: Physical activity not only targets liver health but also improves cardiovascular health and enhances well-being.

The connection between fatty liver disease and body weight is complex and multifaceted. While BMI can provide some insight, it should not be the sole measure of health. A proper focus must be on metabolic health, dietary quality, and lifestyle habits.