Why pizza always tastes so much better on a Friday night.

It’s Friday night, it’s been a huge week, you are exhausted and just looking forward to getting home. The last thing you want to do is think about cooking dinner. The thought of just putting your feet up, maybe watching a movie and ordering takeaway becomes really attractive. When we are stressed, our emotional drivers are likely to lead us to eat high fat foods such as pizza and ice cream.

Dieting is a stress too. Have you ever been on a crash diet, successfully lost some weight only to find that it all goes back on (with a little extra!) in a relatively short period of time? Though if we continuously starve ourselves over an extended period of time, this restriction of calories or kilojoules will actually lead us to live a longer life (just hungry). There are people in the world actually experimenting on themselves to achieve this. I’m not suggesting you do too. Most if us choose not to live with calorie restriction. Life is meant to be enjoyable too isn’t it? Unfortunately if you have some excess kilos you want to lose, your experience is more likely to be one of the merry-go-round of weight off, weight on, weight off, weight on. It is this type of dieting stress, which alters our brain.

Researchers at the University of Pennsylvania put a group of mice on a diet for three weeks. They lost weight. They also showed increased levels of stress hormones and displayed depressive behaviour. An epigenetic* change was noted and that this change persisted even when the mice went back to a normal diet. The mice were then subjected to stress, which resulted in them choosing to eat higher fat mouse food compared to a control group who had not previously dieted.

This outcome suggests that in humans, dieting alters our brain, making it not only more difficult for us to lose weight in the first place but also reprograms our brain on how we deal with future stress and our emotional food choices.

So in order to lose weight successfully, it comes back down to healthy food choices and exercise.

Have you noticed it’s Friday today? How are you going to respond to “what’s for dinner tonight?”

• In epigenetics, an experience can alter the form and structure of the DNA in certain genes.

Ref: Society for neuroscience (2010, Dec 1) Yo-yo dieting alters genes linked with stress