There are a few foods which are considered to be uppers or mood enhancers. Chillies, bananas and of course chocolate for example. As for the latter there have been lots of claims for chocolate over the years and one of them has been a fairly consistent claim that chocolate has a positive impact on mood. Most of the claims have been fairly anecdotal and what little research has been done is either very small scale or have been fairly ropey first publications by students.
However the first systematic review of all of the current high quality research has been published today. In an article titled 'Effects of chocolate on cognitive function and mood: a systematic review' researchers from the Centre for Human Psychopharmacology, in Melbourne Australia and Keel University in the UK have gone through the scientific evidence to find out if there is any really any substance behind the claims.
Firstly they could only find eight scientific, valid and reliable studies of the effect of chocolate, or more properly cocoa flavanols, cocoa polyphenols and methylxanthine, on mood. By any measure 8 studies isn't exactly a lot!
Anyway, when they reviewed these studies they found that five of the studies found clear evidence of either an improvement in mood or a reduction of a negative mood after the consumption of chocolate. Two studies couldn't find any effect and the last one was inconclusive.
Most poeple will take 5 out of 8 as a result!
The question then turns to whether the mood elevation properties of chocolate is actually down to something that actually happens in the brain or it is what scientists call an orosensory effect. In other words does chocolate or something in the chocolate change the brain or it's chemicals in some way or is it a psychological effect based on the taste, smell and texture of the chocolate, probably linked to memories of our youth?
At the moment the research is unclear about what is causing the effect however two studies (oddly the ones that reported no behavioural affect) found an acute change in brain functioning following the consumption of cocoa polyphenols.
Reading between the lines it would appear that it is likely that chocolate or more properly a mixture of cocoa and sugar does have a mood elevation effect and can even help elevate your mood when it is 'down'. to some extent. It also is likely that it is both the association of the feeling we have when eating chocolate (taste, texture and smell) and active ingredients in the sugar and cocoa that bring about a sense of mood elevation. This effect may then amplified bythe orosensory effects of actually eating the chocolate.
There is no evidence yet of how long these effects last or whether it has a compound effect, i.e. the more chocolate you eat the better you feel. More research needs to be done on this.
As to whether chocolate can be used as part of an emotion regulation strategy... You might like to run some of your own experiments! Let me know what you find.
Scholey, A. & Owen, L. (2013) Effects of chocolate on cognitive function and mood: a systematic review. Nutrition Reviews Volume 71, Issue 10, pages 665–681, October 2013