The world is getting fatter and it’s making us sicker. But could rising stress levels be playing an important role in our growing waistlines?

In the past few years, you may have noticed more and more people around you turning away from meat. At dinner parties or family barbecues, on your social media feed or in the news, vegetarianism and its more austere cousin, veganism, are becoming increasingly popular.

Imagine what the world would be like if numbers had specific spatial locations, music had shapes, or colours made sounds. Perhaps you’d experience the bass in the Jamie xx track Gosh as cuboid, metallic and heavy, with spiralling ribbons of synthesiser in the background.

A feeling of apathy or being a little forgetful from time to time is nothing unusual. But for some, this could be an early sign of not getting enough thiamine (also known as vitamin B1). Long term, this can have serious consequences, including an increased risk of developing Alzheimer’s disease.

How do you choose which shampoo to buy? Do you take the advice of your hairdresser or believe the adverts you see in magazines or on television? Perhaps you just opt for the brand on special offer in the supermarket? Most importantly, does it make any difference?

Everybody knows that to lose weight you need to eat less or exercise more – or ideally do both. The evidence supporting the benefits of regular exercise and eating less is overwhelming, but for people looking to lose weight, it remains unclear whether there are extra benefits to be gained from increasing the intensity of workouts.

Roughly 90% of humans are right-handed and this is one of the traits that separates us from most other primates who don’t really show any overall preference for left or right handedness. It’s believed that handedness played an important role in human evolution, with a recent study on the earliest evidence of right-handedness in the fossil record shedding light on when and why this trait arose. Interestingly, the clues were found not in our ancient hands, but in our ancient teeth.

We’re all here because of mutations. Random changes in genes are what creates variety in a species, and this is what allows it to adapt to new environments and eventually evolve into completely new species. But most random mutations actually disrupt the functions of our genes and so are a common source of genetic diseases.

The internet may be the most comprehensive source of information ever created but it’s also the biggest distraction. Set out to find an answer on the web and it’s all too easy to find yourself flitting between multiple tabs, wondering how you ended up on a page so seemingly irrelevant to the topic you started on.

A lot of people will have already made up their mind about whether humans need dairy in their diet and will be thinking that the answer is obviously “yes” or obviously “no”. But nutrition is based on science not opinion – so, here’s the latest research on the matter.

Christmas is a time of year like no other; gifts are exchanged, little-spoken-to relatives are contacted, and appetising treats are consumed with great gusto. Christmas can be both a time of stress and a time of relaxation. But whether you love or hate Christmas it’s pretty difficult to avoid – and so your brain may be altered by the experience one way or another. Here are some of the main facets of the Christmas experience, and how they might affect your brain.

People who regularly go on diets tend to lose weight initially but bounce back and even gain weight after stopping the regime. This phenomenon – dubbed yo-yo dieting – is associated with changes in metabolism and is one reason why the vast majority of calorie-based diets fail. But exactly what causes these metabolic changes has remained a mystery – until now.

Many of us might respond to this question with a resounding yes. It is easy to think that we all got better rest in those halcyon days when summers were long and hot, winters were snowy and life was a bit less frenetic. But even if this is true about your own sleep, is it really true of people as a whole?