People regularly fail to think about what they are eating and many are piling on the pounds as a result, it showed.
Of the 85 per cent who admitted to “unconscious eating”, most said boredom was the main trigger (59 per cent).
Eating to give themselves a treat was the second most common reason (41 per cent) followed by feeling depressed (36 per cent).
TV watching came in fourth place as a trigger for unconscious eating (35 per cent), while snacking in a bid to cheer themselves up came in fifth (25 per cent).
Eating at the weekends was the next most common reason (20 per cent) while in seventh place was people enjoying “me time” (18 per cent).
More than 60 per cent of adults surveyed admitted to eating too much, despite 75 per cent saying they wanted to lose weight.
Almost one in three (30 per cent) admitted not watching what they eat while seven out of 10 think about food every two hours or more.
A total of 22 per cent said they never eat at the table and 37 per cent eat at least one meal a day in front of the TV.
The poll of more than 1,000 people was carried out by the Jenny Craig weight management programme, which has proved a hit with US celebrities.
Obesity expert and GP Ian Campbell said: “Being aware of what and how much we eat is essential to weight management.
“Too often people get the balance wrong – the key to a healthy balanced diet is to be mindful about our eating.”