A scientist convinced 25,000 people to leave urine samples on their stoops - and made a remarkable discovery

Scientists do some pretty strange things to better understand how the human body works.

Take prediabetes, the condition that precedes Type 2 diabetes but usually comes without symptoms.

Today, about half of the US has diabetes or prediabetes. In her book, "The Life Project: The Extraordinary Story of 70,000 Ordinary Lives," Helen Pearson tells the story of the incredible study that taught scientists that prediabetes exists.

In the 1960s, a British medical professor named John Butterfield was watching as more and more patients who complained about being thirsty, tired, and having to constantly visit the bathroom were eventually diagnosed with diabetes (using a test that looked for sugar in their urine). He wondered if there was a better way to identify diabetes, before the symptoms started.

To find out, he organized an incredible study, recruiting 25,701 residents in a British town called Bedford - most of the townspeople over 21. The task? Eat breakfast one Sunday morning, then leave a urine sample at their front door.

Butterfield and a team of volunteers collected all the samples and measured how much sugar was in each person's urine. The incredible result: He could actually see the early stages of diabetes unfolding.

He found that about 1,000 of the town residents already had high levels of glucose in their urine - even though they'd never had any symptoms of diabetes. In fact, some of them already had glucose levels about as high as what a diabetic person would have.

Diabetes didn't just come out of nowhere, Butterfield discovered. It develops gradually, over years - years during which doctors can now try to intervene.

Despite the impressive discovery, the study didn't entirely go according to plan, Pearson writes. Apparently, someone tried to turn in a glass of sherry in place of his actual urine, but was found out.

"You may have made medical history, my boy, but, just to be sure, can you please do it again?" Butterfield reportedly asked the cheater. Science still hasn't found any conditions that would make a person pee pure sherry.