The recommended daily calorie allowance is 2,500 for men and 2,000 for women. The survey followed 4,000 adults as they reported their calorie consumption over four days, while scientists calculated the real number
The data suggests that their men eat more than 3,000 a day while believing they’re eating around 2,000. Women say they consume roughly 1,500 when in fact it’s more like 2,500.
Public Health England chief nutritionist Dr Alison Tedstone told the BBC that the finding isn’t a surprising one as under-reporting of calorie intakes "has always been a feature of all diet surveys".
"Some people forget what they've consumed and some change what they record knowing they are part of a survey.”
But professor John Wass, a consultant endocrinologist and spokesman for the Obesity Health Alliance, told the Telegraph: “This isn’t necessarily about being in denial, but demonstrates the difficulty in calculating the nutritional content of food.”
The significant disparity has also been blamed on a lack of clear labelling on food, excessive portion sizes, alcohol intake, snacking and a gap between a manufacturer's “serving size” and the amount people actually eat in one serving.