A surprising brain discovery could help explain why we overeat fatty foods
Researchers have uncovered a surprising brain-based mechanism that may help explain why fatty foods can be so difficult to resist
Date:
August 13, 2026
Source:
Osaka Metropolitan University
Summary:
A protein inside appetite-controlling brain cells may play an important role in preventing overeating and obesity, particularly when high-fat foods are readily available. Unexpected differences between males and females could also help explain why obesity risk—and responses to weight-loss drugs—can vary.
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FULL STORY
Obesity is a major health problem worldwide and can raise the risk of diabetes, cardiovascular disease, and other metabolic disorders. Many factors can contribute to obesity, but researchers are increasingly interested in the role of high fat foods that are readily available in grocery stores. These foods can be difficult to resist and may encourage people to eat more than they need
Although overeating might seem like a problem that begins in the stomach, appetite is largely regulated by the brain. Scientists still do not fully understand how dietary fat interacts with the neural systems that control hunger, food intake, and body weight
A Brain Protein Linked to Appetite Control
To investigate this connection, a research team led by Professor Shigenobu Matsumura of Osaka Metropolitan University’s Graduate School of Human Life and Ecology focused on optic atrophy 1 (OPA1). This mitochondrial fusion protein is found in hypothalamic MC4R neurons and plays a role in maintaining mitochondrial function and energy metabolism
The researchers compared wild-type mice with mice in which OPA1 had been specifically removed from MC4R neurons. To explore how the protein influences appetite and body weight, the animals were given free access to soybean oil as a
Dietary Fat Produced Different Effects in Males and Females
The results showed that soybean oil increased OPA1 expression in male wild-type mice, but the same increase was not seen in females. Mice that lacked OPA1 ate more food, gained more weight as they aged, and eventually developed obesity
When the animals could freely choose between standard chow and soybean oil, the OPA1-deficient mice consumed more fat and gained additional weight. These effects were especially strong in females
Obesity Drug Response Also Varied by Sex
The researchers also tested setmelanotide, an anti-obesity MC4R agonist. The drug successfully reduced appetite in both control males and OPA1-deficient males. In OPA1-deficient females, however, its ability to suppress appetite was significantly weaker
“Our findings provide key insights into the mechanisms underlying obesity from the perspective of neuronal energy metabolism,” said Professor Matsumura. “The sex differences observed in OPA1 responses and obesity susceptibility may help inform the development of obesity treatments that take them into account, as well as future personalized medicine approaches.”
The findings were published in the FASEB Journal
Materials provided by Osaka Metropolitan University. Note: Content may be edited for style and length
Journal Reference:
- Shigenobu Matsumura, Mizuki Fujiwara, Soyoka Horie, Miona Marutani, Eri Nousou, Nanase Iki, Yuka Yamato, Yui Otonashi, Tsutomu Sasaki, Mina Fujitani, Teppei Fujikawa. OPA1 in MC4R Neurons Regulates Dietary Fat Intake and Body Weight in Mice. The FASEB Journal, 2026; 40 (10) DOI: 10.1096/fj.202600452R
Cite This Page:
Osaka Metropolitan University. “A surprising brain discovery could help explain why we overeat fatty foods.” ScienceDaily. ScienceDaily, 13 August 2026. <www.sciencedaily.com/releases/2026/08/260813045531.htm>.
Osaka Metropolitan University. (2026, August 13). A surprising brain discovery could help explain why we overeat fatty foods. ScienceDaily. Retrieved August 13, 2026 from www.sciencedaily.com/releases/2026/08/260813045531.htm
Osaka Metropolitan University. “A surprising brain discovery could help explain why we overeat fatty foods.” ScienceDaily. www.sciencedaily.com/releases/2026/08/260813045531.htm (accessed August 13, 2026).
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