STUDYFINDS - For scientists, mice often serve as stand-ins for humans. So, what happens when these tiny test subjects are bred to be Olympic-level athletes? Researchers from the University of California-Riverside are shedding light on how exceptionally active animals respond to food and calorie restrictions, with surprising implications for our understanding of diet, exercise, and metabolism.
For over six decades, scientists have been breeding “High Runner” (HR) mice – the rodent equivalent of elite athletes – that voluntarily run nearly three times as much as normal mice. When researchers decided to test how these super-fit mice would respond to severe food restrictions, the results, published in Physiology & Behavior, were nothing short of astonishing.
These mice maintained their incredible running regimens and body weights even when their food was cut by 20%, and they only showed modest changes when food was slashed by 40%. This resilience in the face of drastic calorie reduction flies in the face of conventional wisdom about energy balance and weight loss.
“People often lose about 4% of their body mass when they’re dieting. That’s in the same range as these mice,” says UCR biologist and corresponding study author Theodore Garland, Jr., in a media release.