A Novel Approach to Fattening Them Up
Diet books often warn against eating at night, claiming it leads to weight gain. However, a researcher in Nagasaki, Japan, is turning this principle on its head to raise fatty fish in shorter periods.
Professor Katsuya Hirasaka of Nagasaki University's Faculty of Fisheries is pioneering this unconventional study based on chrono-nutrition, a new scientific field focusing on the timing of food intake. Unlike conventional nutrition studies that emphasize "what" and "how much" is eaten, chrono-nutrition explores the impact of "when" food is consumed.
Hirasaka's research draws inspiration from athletes who consume protein at breakfast to build muscle mass. He applies this concept to fish, aiming to manipulate their biological clocks to increase fat accumulation.
Demonstration tests began in 2022 at the Nagasaki Kakuyo High School's fisheries training facility, providing students with hands-on research experience. They fed fish and measured their growth, gaining valuable insights into university-level research.
"The study was fun and gave me the feel of what it would be like to be in a university," said Kai Yamaguchi, a participating student.
In 2023, Hirasaka compared two groups of white trevally fish, one fed at 8 am and the other at 7 pm. After a month, the night-fed fish exhibited significantly higher levels of neutral fat in their blood and muscles.
"Fish from the shoal fed at night taste so good," Hirasaka remarked, noting their characteristically rich flavor.
Further analysis suggests that white trevally have a 24-hour biological clock activated by morning light. Hirasaka believes the increased fat in night-fed fish is likely due to a metabolic disorder caused by disrupting their natural rhythm.
This research could potentially benefit the "Japan Buri" project, which aims to breed yellowtail for overseas export. Hirasaka's approach, relying solely on natural processes, could be more appealing to consumers than methods involving genetic modification or drugs.
By manipulating the timing of feeding, Hirasaka's research offers a novel and potentially more sustainable approach to raising fatty fish, paving the way for tastier and more efficient aquaculture practices.