Intermittent fasting and fatty liver: Benefits, side effects, and who should avoid it

One is one of the most popular and trending eating habits of this era, while the other – one of the most concerning diseases.

Intermittent fasting and fatty liver.

Intermittent fasting, more popularly known as IF, has become a widely popular method for weight loss and improved metabolism, celebrated by health influencers, celebrities, and tech leaders alike. Thanks to the simplicity of eating within a set time window, skipping meals like breakfast, and losing weight as a consequence, sounds too good to pass up.

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On the other hand, there’s fatty liver disease, which is often linked to obesity, type 2 diabetes, and metabolic syndrome. Currently, it’s affecting an estimated 30.2% of the world's population, while prevalence varies by region. In the Americas and Southeast Asia, the rates are above 40%.

Now, one area where IF has garnered attention is in its potential impact on NAFLD. As the global prevalence of NAFLD rises, effective lifestyle interventions are increasingly sought. IF, with its promise of weight reduction and metabolic improvements, has been proposed as a potential therapeutic approach.

So, how does IF work for NAFLD, if at all? If it works, how to approach it safely? What are the risk factors, and what are the cautions to follow?

Let’s dive deep.

Intermittent fasting (IF) is the practice of cycling between eating periods and fasting, with popular methods like 16:8, where you eat during 8 hours, fast for 16, or the 5:2 approach, where you eat normally for five days, and intake very limited calories on the rest of two days. By cycling between periods of eating and fasting, IF aims to harness the body's natural metabolic processes.

Non-Alcoholic Fatty Liver Disease, widely known as NAFLD (or Metabolic Dysfunction-Associated Steatotic Liver Disease – MASLD), is a condition where excess fat builds up in the liver, not caused by heavy alcohol consumption. It exists in two main forms: NAFL (Nonalcoholic Fatty Liver) with fat but minimal damage, and the more severe NASH (Nonalcoholic Steatohepatitis), which involves inflammation and can lead to cirrhosis and liver failure.

Reduction in liver fat content: Research indicates that IF can lead to a significant decrease in liver fat accumulation. A meta-analysis found that IF, including methods like time-restricted eating (TRE) and alternate-day fasting, resulted in notable reductions in intrahepatic triglyceride (IHTG) levels among individuals with NAFLD.

Weight loss and fat reduction: By promoting weight loss and reducing visceral fat, IF indirectly benefits liver health. Excess fat, particularly abdominal fat, contributes to liver fat accumulation, and its reduction can alleviate the burden on the liver.

Improvement in liver enzymes: Elevated liver enzymes, such as ALT and AST, are markers of liver inflammation and damage. Studies have shown that IF can lower these enzyme levels, indicating reduced liver inflammation and improved liver function.

Enhanced insulin sensitivity: Insulin resistance is a hallmark of NAFLD. IF has been associated with improved insulin sensitivity, which can help in managing blood sugar levels and reducing the risk of progression to type 2 diabetes.

Nutrient deficiencies: Restricting eating windows may lead to inadequate intake of essential nutrients, including vitamins and minerals. This can result in deficiencies that affect overall health and liver function.

Hormonal imbalances: Prolonged fasting may disrupt hormonal balance, affecting reproductive hormones and thyroid function. This is particularly concerning for individuals with existing hormonal disorders.

Increased risk of gallstones: Extended periods of fasting can lead to the formation of gallstones, as the gallbladder doesn't empty regularly. This condition can cause pain and complications, especially in individuals with a history of gallstones.

Potential for disordered eating patterns: The restrictive nature of IF can lead to unhealthy relationships with food, including binge eating during non-fasting periods. This is especially risky for individuals with a history of eating disorders

While IF may offer benefits for some individuals with NAFLD, it is not suitable for everyone. The following groups should exercise caution or avoid IF:

Pregnant or breastfeeding women: Nutritional needs are heightened during these periods, and fasting may compromise both maternal and fetal health.

Children and adolescents: Growing bodies require consistent nutrient intake, and fasting can interfere with growth and development.

Elderly individuals: Older adults may be at increased risk of nutrient deficiencies and muscle loss due to fasting.

Individuals with eating disorders: The restrictive nature of IF can exacerbate disordered eating behaviors and should be avoided.

Individuals with certain medical conditions: Those with conditions such as diabetes, heart disease, or liver cirrhosis should consult healthcare providers before attempting IF.