THE post-holiday blues last for an average of five days for Brits according to new research, with a lack of concentration at work revealed as the worst side effect.

The study of 2,000 British workers, conducted by British Summer Fruits, found that it takes an average of four days to reach their usual level of productivity after returning to work, with one in 10 (13 per cent) admitting that it can take them a staggering 10 days to get back into work mode.

And bosses should beware as the lack of concentration was found to have a knock-on effect on Brits’ productivity at work.

Nearly a fifth of those questioned (17 per cent) admit to making mistakes on important work, with a similar number missing deadlines (16 per cent) and one in six (15 per cent) spending more time on social media in work time after a break.

The study also found that with beach body fears behind them, a third of workers (33 per cent) fall into the trap of opting for junk food when feeling low – with two in five (37 per cent) reaching for chocolate, a fifth (21 per cent) eating biscuits and a similar number drowning their sorrows in a glass of wine (17 per cent).

These eating habits last for nine days, almost double as long as the post-holiday blues.

Surprisingly, nearly three quarters of those questioned (70 per cent) know that food can affect mood but only a quarter (28 per cent) try to eat healthily to combat the blues. However recent research has shown that nutrients found within fruits like berries boost blood flow to the brain1, a key factor which can increase productivity.

Leading nutritionist Dora Walsh said: “Low mood and low concentration are key symptoms of the post-holiday blues but a snack of sweets will only exacerbate this by giving people a sugar high and an almighty crash soon after.

"New research conducted this year found that berries can support brain function by helping to prevent mental decline2, so berries can be the booster you need when the day is dragging on.

“Berries are high in resveratrol polyphenols which keep our blood flowing to the brain – essential when trying to catch up on a week’s work and battle the dreaded email inbox. Good blood flow increases alertness which can improve cognition and brain function.”

Brits are likely to have a laissez-faire attitude to getting over the blues, with two in five (38 per cent) choosing to do nothing but ride them out and cope with the lack of concentration – despite noticing an average of 24 colleagues also suffering.

A spokesperson for British Summer Fruits said: “Many people reach for the junk food when feeling low, but research has actually shown that certain foods are better at improving the mood and giving us a spring in our step.

"A study conducted earlier this year found that strawberries are the fruit that makes us the happiest3, which is a delicious way to banish the post-holiday blues.”

Despite suffering with the blues, Brits admit they are not as sympathetic about colleagues’ post-holiday plight. Rather than offer support, over a third (37 per cent) would let a colleague suffer and two fifths (19 per cent) would tell them to pull themselves together.