It could be one of the biggest developments in terms of dieting so far this decade: scientists in the UK have created a five-minute test that can measure biological markers in urine that are created when certain foods are broken down, allowing medical care providers to actually figure out a person’s exact diet by examining their pee rather than rely on the patient’s own flawed memory and diet tracking.

It’s a finding that could pave the way to better diet plans, as most people aren’t very good at tracking what the eat, frequently overestimating how much healthy food they eat while downplaying how much unhealthy food is consumed. This new test could specify exactly what foods are eaten, like red meats, veggies, chicken and fish, for example, as well as measure the amount of fat, sugar, and fiber consumed.

There’s more development work to do on the test, but it is an incredibly promising development that could be weaved into weight loss programs and help better inform doctors about the eating habits of a patient. The findings were published in the journal Lancet Diabetes and Endocrinology, and the study involved 19 volunteers who followed various diets and then submitted urine samples to researchers.

Professor Gary Frost, senior author of the study from the Department of Medicine at Imperial said: “A major weakness in all nutrition and diet studies is that we have no true measure of what people eat. We rely solely on people keeping logs of their daily diets — but studies suggest around 60 per cent of people misreport what they eat to some extent. This test could be the first independent indicator of the quality of a person’s diet — and what they are really eating.”