News
Article
Study Finds Rapid Dietary Effects On Brain Insulin and Obesity Risk
Author(s):
A brief period of overeating ultra-processed, high-calorie snacks could lead to liver fat accumulation and temporary disruption of brain insulin action.
The link between brain insulin sensitivity and weight regulation is well-established; however, the speed with which dietary changes can impact this essential brain function is unclear. New study findings published in Nature Metabolism evaluated how short-term overconsumption of high-calorie, sweet, and fatty foods affects brain insulin responsiveness and liver fat acclamation among individuals with potential early drivers of obesity.1
Image credit: Maya Kruchancova | stock.adobe.com
Obesity impacts over 1 billion individuals globally and is declared as a body mass index (BMI) of 30 or more. Factors such as poor diet and limited exercise are often the cause of the chronic illness, but other influences in the body can lead to obesity. Given the vast number of individuals impacted, the World Health Organization (WHO) has confirmed obesity as an epidemic.2,3
In Germany, nearly 16 million individuals are affected by obesity. In a study led by the University Hospital of Tübingen, the German Center for Diabetes Research (DZD), and Helmholtz Munich, researchers aimed to assess insights into the cause of type 2 diabetes and obesity, along with the brain’s connection to these diseases. Specifically, the researchers analyzed how insulin performs in the brain and impacts an individual’s normal weight.1,2
"We assume that the brain's insulin response adapts to short-term changes in diet before any weight gain occurs and thus promotes the development of obesity and other secondary diseases,” Andreas Birkenfeld, Medical Director of Internal Medicine IV, Director of the IDM, and DZD Board Member, said in a news release.2
A total of 29 male individuals of average weight were included in the nonrandomized controlled study. The individuals were split into 2 groups, and the first group was required to supplement their regular diet with 1500 kcal from highly processed, high-calorie snacks for 5 consecutive days. The group resumed their regular diet for 7 days as the control group remained on their steady diet throughout the study. Follow-ups were conducted after the 5-day and 7-day consumption periods.1,2
“Interestingly, in our healthy study participants, the brain shows a similar decrease in sensitivity to insulin after a short-term high calorie intake as in people with obesity,” lead study author Stephanie Kullmann, professor at the Tübingen University Hospital for Diabetology, Endocrinology, and Nephrology, said in a news release. “This effect can even be observed one week after returning to a balanced diet.”2
The researchers used magnetic resonance imaging (MRI) to assess the liver’s fat content and brain’s insulin sensitivity, demonstrating that the fat content of the liver of the first group increased following the boosted calorie intake. Further results found that the significantly lower insulin sensitivity in the brain compared to the control also continued 1 week after returning to the normal diet.1,2
"Our findings demonstrate for the first time that even a brief consumption of highly processed, unhealthy foods (such as chocolate bars and potato chips) causes a significant alteration in the brain of healthy individuals, which may be the initial cause of obesity and type 2 diabetes," Kullmann said in a news release.2
However, the study’s small sample size restricts how broadly the findings can be applied, as the results did not detect changes in peripheral insulin sensitivity following the 5-day high-calorie diet.1,2
The findings suggest that a brief period of overeating ultra-processed, high-calorie snacks could lead to liver fat accumulation and temporary disruption of brain insulin action in men. The study authors noted that the results highlighted how rapid the brain’s insulin response can adapt to short-term dietary changes, even before noticeable weight gain.1,2
