Why do some people with obesity develop type 2 diabetes?

• People with obesity are at higher risk of developing insulin resistance and type 2 diabetes than those of a healthy weight.
• However, the conditions to develop insulin resistance do not affect everyone with obesity.
• Now, scientists investigating why some remain healthy and others do not have discovered that adipose (fat) tissue may influence cell function.
• Their research, which they conducted in mouse models, suggests that, in some individuals, obesity disrupts the function of macrophages — which clean up cell fragments — leading to inflammation and metabolic disorders.

According to the World Health Organization (WHO), the number of people with obesity worldwide has tripled in the past 50 years. While the United States and Europe top the scale, South East Asian and African countries are fast catching up.

People with obesity have a body mass index (BMI) of more than 30, although it must be remembered that BMI alone cannot determine whether that mass is made up of muscle or fatty tissue.

More usefully, the WHO defines obesity as “abnormal or excessive fat accumulation that presents a risk to health” together with a BMI of more than 30.

Obesity increases the risk of several health conditions, which include:

However, many people with obesity will not develop these conditions, and scientists at the University of Gothenburg, Sweden, may have found a reason why some are more likely to progress to metabolic disorders than others.