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.”
Doris’s passion for writing started to take shape in college where she was editor-in-chief of the college newspaper. Even though she ended up working in IT for more than 7 years, she’s now back to what he always enjoyed doing. With a true passion for technology, Doris mostly covers tech-related topics.