The research also showed that many employees (53%) believe there is a widespread culture of working through their lunch breaks and continually working over their designated hours.
Commenting on the findings, TUC general secretary, Frances O'Grady, said: "These figures shine a spotlight on Britain's long-hours culture. Far too many employees are failing to take lunch because they have too much work to do.
"It is essential that employers recognise the damage this can do to their staff and to the productivity of their workforce.
"Workers who skip lunch and don't take time away from their desks in the middle of the day are likely to become less productive as the day wears on and are also taking risks with their health."
She added: "We need to change the culture - prevalent in far too many workplaces, that it is acceptable to eat lunch at your desk, and not leave your workspace."
Alison Clark, spokesperson for the British Diabetic Association (BDA), said: "Of course, from time to time we have all sat at our desk and worked through lunchtime or two.
"However, this should not be allowed to become the norm. Indeed, eating lunch at your desk should be an occasional occurrence.
"Eating at your desk can be a fast track to piling on unwanted weight. For example, it is far too easy to partake in a bit of 'mindless eating' while working away at your desk.
"While you mind is fixed firmly on tasks at hand, your actual hand is automatically dipping into a whole raft of treats lying around on your desk.
"Also, working through lunchtimes often means a quick dash to the local sandwich shop without enough time to properly read food labels and understand what you are about to eat and this type of 'grab and go' habit can soon add up."
