Why BMI Is Important in the Diagnosis of NASH

BMI stands for body mass index. BMI is a simple formula that uses your height and weight to determine whether you are underweight, normal weight, or overweight. It also indicates whether you may have obesity.¹

BMI is an easy-to-use tool that can help signal weight-related conditions such as type 2 diabetes, metabolic syndrome, and obesity. BMI also can be used to determine your risk for liver diseases such as nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). NASH is more advanced form of NAFLD.^1,2

It's important to note that BMI can have many limitations, including not being a direct measure of body fat. BMI is one tool that doctors can use to help diagnose NASH, but it is not the only thing that matters in a diagnosis.⁷

Why BMI matters for a healthy liver

BMI can be helpful in assessing liver health. A high BMI may mean that you have excess body fat. Excess fat can build up in the liver. This fat buildup can impact how your liver functions, and it can result in NAFLD.^1,2

The liver is a vital organ that performs many functions to keep you healthy. This includes tasks like:³

• Detoxifying the blood
• Making bile, which aids in digestion
• Storing glycogen and vitamins

If NAFLD is left untreated, it can progress to NASH. With NASH, in addition to fat buildup, there is inflammation and cell damage in the liver. This can lead to even more serious health issues like cirrhosis (permanent scarring of the liver) and liver cancer.⁴

Ideal BMI range for reducing NAFLD and NASH risk

The higher your BMI, the greater your risk of NAFLD and NASH. A high BMI can be linked to other health conditions like type 2 diabetes, high cholesterol, and obesity. These conditions increase the risk of developing NAFLD and NASH.^1,2,5

You can find out your own BMI using this online calculator. According to the Centers for Disease Control and Prevention (CDC), BMI scores fall into the following categories:¹

• Less than 18.5 – underweight
• 18.5 to 24.9 – normal weight
• 25 to 29.9 – overweight
• 30 or above – obese

Generally speaking, a BMI between 18.5 and 24.9 is the ideal range for reducing the risk of NAFLD and NASH. However, it is not just about the number. It is important to maintain a healthy balance of muscle and fat.¹

In diagnosing NAFLD and NASH, doctors take many things into account. They use BMI as well as other health indicators to get a comprehensive view of liver health. Other health indicators may include:^1,2,5

• Waist circumference
• Co-occurring health issues
• Certain lifestyle factors

NAFLD in people who do not have a high BMI

While high BMI is a risk factor for NAFLD and NASH, these conditions can occur in people who are not overweight. A person may have a healthy BMI and still develop NAFLD. This may be due to:⁵

• Genetics
• Hormones
• Lifestyle factors
• Body composition

Even with a healthy BMI, fat can still collect in the liver. Living a healthy lifestyle and getting regular checkups are crucial to maintaining liver health.⁵

Weight loss and maintenance

The first step in treating NAFLD and NASH is to lose weight. Research has shown that weight loss is one of the most effective ways to treat these conditions. Weight loss:^2,3,6

• Reduces fat in the liver
• Improves liver function
• Helps manage other risk factors like diabetes and high cholesterol

Try these tips to maintain a healthy weight:⁶

• Eat a balanced diet.
• Be mindful of portion sizes to avoid overeating.
• Stay hydrated.
• Exercise regularly.
• Limit sugary and processed foods.
• Stay active throughout the day.
• Try to get 7 to 9 hours of quality sleep each night.