The report finds that if the reported level of calories consumed in official statistics is correct then the nation would be losing weight, not gaining it.
The Behavioural Insights Team states that policies to reduce calorie consumption have an important part to play in an obesity strategy.
The report found that although attempts to increase physical activity should be part of the policy mix for obesity, they should not act as a distraction from the central importance of reducing calorie consumption.
To maintain the current weight using the average height, age and weight for adults in 2013, the report said an energy requirement of around 2446kcal per day is required, which is substantially larger than estimates of calorie intake presented in official statistics.