Is “Social Jetlag” making you fat?

If you love sleeping until noon over the weekends you might want to re-think your habits once you read this blog...

According to a study published this month in the journal Current Biology, researchers from the Universities of Munich and Groningen have shown that people with different sleep schedules on working days and free days (what the researchers called Social Jetlag) had triple the chances of being overweight.

Social jetlag is "the discrepancy between what our body clock wants us to do and what our social clock wants us to do," says Till Roenneberg, a professor at the University of Munich's Institute of Medical Psychology, in Germany. "It almost looks as if people on a Friday evening fly from Paris to New York, and on Monday morning they fly back again.”

Roenneberg and colleagues have surveyed the sleep habits of more than 65.000 European participants, comparing their sleep duration, sleep timings and patterns over working days and free days. They have found out that the Body Mass Index (BMI) of overweight people tended to be higher in those with a bigger discrepancy of sleep between their biological and social clocks (sleep discrepancy did not explain variations in body mass among those with a normal BMI).

These results confirmed previous data that linked higher BMI to sleep deprivation and irregular sleep schedules. Particularly, various studies have found an increased risk of obesity, as well as chronic diseases such as diabetes, among shift workers.

Some of the proposed explanations for the link between shift work and obesity, such as irregular meal times and metabolism disruptions, may help explain these social jetlag findings as well, Roenneberg says. "With social jetlag, we're forced to eat at times when the body doesn't want to eat, or isn't prepared for digesting food properly," he says. "All these things coming together might influence the way you digest food and how you incorporate it into your body fat. The result is that you become overweight or obese."

This study also explained why “teenagers show the largest discrepancy in sleep duration between free days and workdays”. Amongst other obvious reasons (such as playing computer games until late or chatting on their computers/mobiles :0)) this is because developmental changes in their circadian clock are not matched by the school start timings, changes particularly evident and fundamental at this phase.

So what can we do?

Adjusting our sleeping patterns isn’t easy. We just can’t simply rely on our biological clocks to wake up, we have work schedules to keep up to but paying more attention to our body clocks may be good start.

And here goes a link if you want to do a check-up to your sleep

http://www.webmd.com/sleep-disorders/sleep-disorders-health-check/default.htm 

Let's give this a thought, shall we?

A sweet treat for Easter!

Does eating chocolate regularly make you thinner? Not really but don’t loose all your hope because…

Scientists from the University of California believe that there is a link between regular chocolate consumption and a lower body mass index (BMI*).

In a recent study published in the journal Archives of Internal Medicine (March 26^th), Dr. Beatrice Golomb and colleagues analysed the diet, exercise and mood levels of about 1000 healthy US individuals and found that those who ate chocolate a few times a week were, on average, slimmer than those who ate it occasionally.

This link remained even when other factors were taken into account, such as the calorie intake (frequent chocolate consumption was actually linked to more overall calories), the frequency of exercise or the mood levels.

According to the authors, it is the how often you eat chocolate that is important rather than how much you eat (they found no link between the quantity of chocolate consumed and the BMI).

Previous studies have shown that chocolate consumption has other metabolic benefits, such as insulin sensitivity, blood pressure and cholesterol levels. To Dr. Golomb and her team, this study “now extends the favourable associations of chocolate to metabolic factors”.

“Chocolate products are often rich in sugar and fat, contributing to assumptions that chocolate boots BMI”, says the team in this report. Nonetheless, one possible explanation for these findings is that the antioxidants present in chocolate (called catechins) contribute to lean muscle mass and reduce weight, as shown previously in studies in rodents. The team suggests that a clinical trial in humans is now needed to see if this is indeed the case.

Study details:

1) The study analysed data from 1018 healthy men and women aged 20 to 85 years old (average 57). 972 patients had their BMI calculated (average 28) and 975 answered the food frequency questionnaire.

2) Data was collected regarding chocolate consumption, calorie intake, saturated fat intake, fruit and vegetables consumption (used as controls), exercise and mood levels.

3) Results have shown that on average the individuals ate chocolate 2 times/week and exercised 3.6 times/week. Chocolate consumption frequency was linked to greater calorie and saturated fat intake and higher mood scales. It was not linked to greater activity but to lower BMI.

In conclusion, before you reach for a chocolate bar next time, think that it is, to a great extent, your diet composition that will influence your BMI, rather than solely the quantity of what you eat.

But, hey, it is Easter, so give yourself a treat (preferably dark chocolate that has antioxidants that fight free radicals ;0) )!!!

Let's give this a thought, shall we?

* BMI is a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems. It is calculated by dividing one’s weight by the square value of one’s height. Normal values range from 18.5 to 24.9. Bellow that those values a person is considered underweight. Between 25 and 29.9 a person is overweight and above 30 a person is obese.