DIETING makes people feel depressed because cutting out fatty foods alters their brain, according to a new study. Watching other people tuck into calorie-laden food while dieters munch on “rabbit food” is enough to make anyone feel blue.
And now it’s official as the scientists say ditching a high-fat diet triggers chemical changes in the brain that could make people enter a cycle of poor eating.
Such fatty and sugary foods cause chemical changes before obesity even occurs, with University of Montreal researchers likening going on a diet to drug withdrawal.
Dr Stephanie Fulton said: “By working with mice, whose brains are in many ways comparable to our own, we discovered that the neurochemistry of the animals that had been fed a high fat, sugary diet were different from those who had been fed a healthy diet.
“The chemicals changed by the diet are associated with depression. A change of diet causes withdrawal symptoms and a greater sensitivity to stressful situations, launching a vicious cycle of poor eating.”
The researchers fed one group of mice a low-fat diet, and a high-fat diet to a second group over six weeks. They then monitored how the different food affected the way the animals behaved.
Fat represented 11% of the calories in the low-fat diet and 58% in the high-fat diet, causing the waist size in the second group to increase by 11%, which is not yet obese.
The relationship between rewarding mice with food and their resulting behaviour and emotions was then measured, and the brains of the mice were studied to see if there had been any changes.
Results showed mice that had been fed the higher-fat diet exhibited signs of being anxious – such as avoiding open areas – and their brains had been altered.
A molecule the researchers looked at, dopamine, enables the brain to reward people with good feelings and encourages them to learn certain kinds of behaviour.
They found another molecule involved in memory, which causes the production of dopamine, was more activated in the brains of the higher-fat fed mice.
It is all linked to what is known as Creb (cAMP response element-binding protein). “Creb is more activated in the brains of higher-fat diet mice and these also have higher levels of corticosterone, a hormone that is associated with stress.
“This explains both the depression and the negative behaviour cycle.
“It’s interesting that these changes occur before obesity. These findings challenge our understanding of the relationship between diet, the body and the mind.
“This raises the question as to how we might support people psychologically as they strive to adopt healthy eating habits.” – The Daily Telegraph