Through good times and bad, the humble chocolate bar has always been there for us. 

Whether we're treating ourselves after a hard day's work, trying to drown our period cramps in a sea of hot cocoa, or simply just giving in to those pesky sugar cravings, chocolate is one of the few things we can always count on to put a smile on our face. 

Sure, it's all about moderation, but there are definitely worse ways to relieve stress – and science can prove it. 

Two studies from the Loma Linda University in California have found the the consumption of chocolate can have a positive effect on stress levels, as well as inflammation, mood, memory and immunity. 

However, before you start chomping down on that last emergency Easter egg, you should know that not all chocolate is made equal.

If you want to enjoy all the benefits listed above, you need to be eating dark chocolate with over 70 per cent cocao. 

The study looked at how the flavonoids contained in dark chocolate impacted the human brain, and found that the higher concentration of cacao, the more beneficial effects are to be had.

"For years, we have looked at the influence of dark chocolate on neurological functions from the standpoint of sugar content – the more sugar, the happier we are," says lead researcher Lee S. Berk.

 "This is the first time that we have looked at the impact of large amounts of cacao in doses as small as a regular-sized chocolate bar in humans over short or long periods of time, and are encouraged by the findings.

"These studies show us that the higher the concentration of cacao, the more positive the impact on cognition, memory, mood, immunity and other beneficial effects."

We can't argue with that…