In the largest study of its kind, scientists at the University of Aberdeen and the Chinese Academy of Sciences looked to see what makes mice gain weight: is it fat? Is it the carbs or the proteins?
Considering that food contains all three, it’s difficult to find out which type of diet leads to gaining weight.
Scientists couldn’t study humans, because they cannot control what the subjects eat for very long periods, so studies on animals were the best approach to get closer to an answer: what makes us fat?
The Answer is: FAT
In their study, which was published on 12 July in the journal Cell Metabolism, scientists developed 30 diets to feed their lab mice. The mice had different types of food, which varied in contents of carbs, fat, and protein.
The mice received different diets for three months, which (in humans) would be equal to nine years. Scientists did more than 100,000 measurements of the mice’s body weight and changes in body fat using a very small MRI machine.
Lead author of the study, Professor John Speakman, explained their results:
“The result of this enormous study was unequivocal – the only thing that made the mice get fat was eating more fat in their diets.”
He then explains that carbs that accounted for up to 30% of the calories and came from sugar did not make the mice fat. Neither low protein (5%) had increased the intake. He concluded that:
“These effects of dietary fat seemed to be because uniquely fat in the diet stimulated the reward centers in the brain, stimulating greater intake.”
Speakman knows that the study has its limitations since it was based on mice and not on humans, but mice and humans have a lot in common, especially the physiology and metabolism.
He added that they could never do this study on humans, considering they would have to control their diets for years, so he concludes “the evidence it [the study on mice] provides is a good clue to what the effects of different diets are likely to be in humans.”
Rex Austinwas born and raised in Thunder Bay Ontario on the shores of Lake Superior. Apart from running his own podcast (Ice Fishing And Other “Cool” Things), he spends his time canoeing and backpacking in Northern Ontario.. As a journalist Rex has published stories for Global News (Thunder Bay) we well as Buzz Feed and Joystiq. As a contributor to Great Lakes Ledger, Rex most covers science and health stories. Contact Rexhere