In a new study, mice were put on 29 different diets for the equivalent of 9 'human years' in an attempt to discover exactly what causes mammals to gain weight.

　　(Image: iStockphoto)

　　

　　What happened?

　　"The result of this enormous study was unequivocal – the only thing that made the mice get fat was eating more fat in their diets," said Professor John Speakman, who led the study between the University of Aberdeen and the Chinese Academy of Sciences.

　　The study looked at key components of our daily diets: fat, carbohydrate, refined sugar and protein.

　　

　　(from Cell Press)

　　

　　Scientists and the public have long argued which of these is to blame for our expanding waistlines. 

　　

　　(Image: Blend Images)

　　A few decades ago, fat was considered the main culprit.

　　But more recently carbohydrates, particularly refined sugar, have become the number one enemy for those seeking a slimmer frame.

　　According to TechnologyNetworks, more recently, "attention has turned to protein" with the hypothesis that "when the protein content of our diet falls, we eat more food to meet our target protein intake".

　　Therefore high carbohydrate, high fat and low protein have all been implicated in weight gain.

　　But the results in this new new mice study are clear.

　　Only diets with high fat led to weight gain. 

　　

　　Sugar is not the cause of weight gain in mice (Image: Photographer's Choice)

　　The results show diets with high "carbohydrates including up to 30% of calories coming from sugar had no effect" on weight gain.

　　Combining sugar with fat had no more impact than fat alone.

　　There was no evidence that low protein (down to 5%) stimulated greater intake'" of food.

　　Professor Speakman says "A clear limitation of this study is that it is based on mice rather than humans.

　　However, mice have lots of similarities to humans in their physiology and metabolism, and we are never going to do studies where the diets of humans are controlled in the same way for such long periods. So the evidence it provides is a good clue to what the effects of different diets are likely to be in humans." (Mirror Online)