Over 60% of adults surveyed admitted to eating too much, despite 75% saying they wanted to lose weight.
Almost one in three (30%) admitted not watching what they eat while seven out of 10 think about food every two hours or more.
A total of 22% said they never eat at the table and 37% 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.”
Karen Barber, nutritionist for the programme, said: “From our experience unconscious eating is one of the most common challenges our personal weight management coaches manage with our clients.”
Research suggested that people on the Jenny Craig programme lose more than three times as much weight as those using other diets, have lower cholesterol levels, better fitness and eat more fruit and veg.