NEW RESEARCH SUGGESTS THAT OBESITY affects the brain in sex-dependent ways. Specific brain parts appear different when we compare males and females with high body mass indexes. Regarding obesity, men and women have different brains, so tailoring management strategies by sex may help fight obesity.

Obesity is a significant public health issue that affects people of all ages, genders, and socioeconomic backgrounds. The World Health Organization (WHO) states that over one billion people worldwide are obese. This estimate includes 650 million adults, 340 million adolescents, and 39 million children.

The World Health Organization explains that obesity impacts most body systems, including the heart, liver, kidneys, joints, and reproductive system. It can lead to various non-communicable diseases (NCDs), including type 2 diabetes, cardiovascular disease, hypertension, stroke, cancer, and mental health issues. Individuals with obesity are three times more likely to be hospitalized for COVID-19.

Now comes a brain imaging study that analyzed brain differences between females and males with a high body mass index (compared with those with a normal BMI).

Obesity — Men and women have different brains

The University of California, Los Angeles (USA) researchers analyzed data from magnetic resonance imaging (MRI) scans, clinical characteristics, and medical histories. They aimed to identify sex-specific brain processes that lead to obesity. Might men and women develop obesity for different reasons?

Historical studies examined brain images to see how obesity affects eating habits. Few studies have looked to see how the brains of obese individuals might differ in males and females.

Here are the current study results:

Specific brain parts differed between males and females with a high body mass index (BMI). The researchers offer that tailoring management to an individual’s sex may be essential to combating obesity.

In other words, investigating sex as a biological variable is key to determining obesity development and management response.

Obesity — Study details

The study involved a review of data from 183 participants. Of these, 78 had a high body mass index, and 105 had a normal BMI. The researchers used several brain scan forms. They also collected survey data on early life experiences, mood, and eating habits.

Using a method known as DIABLO, the scientists tried to accurately discern differences between those with a high versus a normal BMI. They also assessed differences between males and females with high BMI.

The analysis could effectively differentiate high BMI from normal BMI participants with 77 percent accuracy. Also, males with high body mass indexes could be distinguished from females with high BMI with 75 percent accuracy.

The study discovered differences in specific brain regions when comparing males and females. These variations appeared to be related to mental health, early life experiences, and touch sense.

Women with obesity exhibited changes in emotion-related brain centers associated with higher compulsive eating levels. On the other hand, in men, brain regions related to eating behavior and obesity were linked to gut sensations linked to abdominal discomfort and hunger.

Moreover, women with a high BMI had more significant brain signatures and lower mental health scores than men. Females may be more vulnerable to developing food cravings and addictions.

My take — Obesity and sex differences in the brain

This exploration of sex differences is unusual; of 199 studies found by the researchers, only 13 examined sex differences.

Key brain signatures are changed in obese individuals, affecting how an individual views food (and food cravings), eating patterns, and obesity. By looking at how these brain patterns differ by sex, the researchers open the door to a better understanding of the pathways by which women and men develop obesity.

In summary, there are gender differences in obesity. The reasons for the variation are unclear. By better understanding how the brains of those with obesity differ from those without it, we may develop better diagnostic and management tools.

Because the study was cross-sectional (comparing one group to another), the researchers cannot establish any causal relationships. We do not know if the brain MRI differences between men and women, based on body mass index, are due to gender or BMI. There may be some other factors.

Second, the researchers could have used more accurate measures of obesity, including waist-hip ratio or fat measurements (visceral adiposity).

Finally, I don’t think this provocative study has any implications for the current management of obesity. Given that those with a higher BMI report significantly greater childhood traumas, anxiety, depression, a tendency to notice body symptoms with hypervigilance, and other chronic stressors, we need to do a better job addressing these issues.