Four metrics to characterise population overweight are described.Behavioural Risk Factors Surveillance System data were used to estimate the weight the US population needed to lose to achieve a BMI < 25. The metrics for population level overweight were total weight, total volume, total energy, and energy value.About 144 million people in the US need to lose 2.4 million metric tonnes. The volume of fat is 2.6 billion litres-1,038 Olympic size swimming pools. The energy in the fat would power 90,000 households for a year and is worth around 162 million dollars.Four confronting ways of talking about a national overweight and obesity are described. The value of the metrics remains to be tested.