Looking for another reason to avoid the Greasy Spoon on your lunch break?
Oxford University scientists have provided a doozy. In their study, rats receiving a fat-laden diet exhibited a 50% reduction in exercise capacity and diminished cognitive skills after just 9 days.
The findings could have implications for Average Joes who eat Sloppy Joes for lunch, athletes in search of an edge, and people at risk for metabolic syndrome and diabetes, say the authors who published their findings in the FASEB journal.
“We found that rats, when switched to a high-fat diet from their standard low-fat feed, showed a surprisingly quick reduction in their physical performance,” lead author Andrew Murray told BurrillReport.
The physiology behind the observations is fairly well understood. Exercise endurance is a function of the amount of oxygen that can be delivered to muscles and the efficiency with which muscles can extract the energy contained within the chemical bonds of the nutrients supplied to them (a process known as oxidation)
Fat oxidation is less efficient than the oxidation of simple carbohydrates like glucose.
For their study, Murray and Co. fed 42 rats a standard diet containing 7.5% fat, and measured exercise capacity as the maximal time they were able to run on a treadmill. They assessed short-term memory in the subjects using a maze task.
The scientists then switched half the rats to a diet in which 55% of the calories were derived from fat and reassessed the rats’ endurance and cognitive abilities.
Junk food diets can easily approach the 55% fat content used by the scientists.
By day 9, rats on the high fat diet managed to run only half as far as their counterparts. They were also making mistakes about 17% earlier in the maze task, suggesting diminished cognitive skills.