Belly fat affects brain performance

Why belly fat is bad for thinking

In previous studies, a connection between existing abdominal fat and reduced brain performance was found several times. An American research team has now deciphered the reasons for this connection. Obviously, belly fat affects our immune system in a negative way.

Researchers at Iowa State University showed for the first time why fewer muscles and more body fat are associated with reduced thinking. According to the study, belly fat releases inflammatory messengers, which lead to a permanently increased activity of the immune system in the brain, which affects the ability to think. The results were recently published in the journal "Brain, Behavior, and Immunity".

Belly fat affects our immune activity

According to the current study, fewer muscles and more body fat are directly linked to changes in the immune system and less flexibility in thinking. This can lead to a greatly reduced cognitive performance, especially in overweight older adults.

Course of study

The team led by Auriel Willette, Assistant Professor of Food Science and Human Nutrition, and Brandon Klinedinst, Doctor of Neuroscience, analyzed data from more than 4,000 UK middle to advanced age participants. Measurements of lean muscle mass, abdominal fat and subcutaneous fat were available from all subjects. The researchers examined how the cognitive performance of the participants changed over a period of six years.

The critical 40s and 50s

Willette and Klinedinst discovered that especially people who had increased fat levels between the ages of 40 and 60 lost their cognitive performance faster with increasing age. In contrast, higher muscle mass seemed to be a protective factor. These relationships remained unchanged, taking into account chronological age, educational level and socio-economic status.

Age doesn't seem to have much of an impact on IQ

"The chronological age does not seem to be a factor in the fact that the IQ decreases over time," explains Willette. It seems much more the biological age that is responsible for the mental degradation. In this case, the biological age can be determined by the amount of fat and muscle.

Be careful from the age of 40

Generally, as people get older, they start gaining fat and losing lean muscle. The researchers therefore point out that training routines become increasingly important with increasing age. The trend towards muscle loss is even more likely to start in women than in men.

How belly fat affects the immune system

In the current study, the relationship between abdominal fat and poorer IQ is explained by changes in the white blood cells. Accordingly, lymphocytes and eosinophils are increasingly formed in women in the course of increased body fat. In contrast, in men there is an increased formation of basophils with an increasing proportion of body fat. Increasing muscle mass had no impact on the immune system, which is why, according to the researchers, the BMI alone is not a suitable method for assessing this connection.

Can trigger belly fat in Alzheimer's

The researchers even suspect that excessive body fat increases the risk of Alzheimer's disease. According to the current study situation, this is only a guess. "Further studies would be necessary to see whether people with less muscle mass and more fat mass are more likely to suffer from Alzheimer's disease and what role the immune system plays," concludes Klinedinst.

Losing weight is good for the brain

When it comes to good resolutions for the coming year, the study team recommends eating healthier and exercising more. "If you eat healthy and walk faster, it could help you stay mentally longer," advises Willette. (vb)

Author and source information

This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.

Graduate editor (FH) Volker Blasek


  • Auriel Willette, Brandon Klinedinst, Colleen Pappas, u.a .: Aging-related changes in fluid intelligence, muscle and adipose mass, and sex-specific immunologic mediation: A longitudinal UK Biobank study, Brain, Behavior, and Immunity, 2019,
  • Iowa State University: Changes in the immune system explain why belly fat is bad for thinking (accessed: December 18, 2019),

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