"Diabetes is at epidemic levels in this country," said Mandell, who has Type 2 diabetes. The walk is "creating a true awareness of diabetes and reaching into the hearts and minds of over 100 million people."
Sporting a hunter-orange vest visible from a mile away, Mandell spent Tuesday and Wednesday walking east along the Interstate 90 shoulder in Gallatin County. A white Land Rover painted with the words "Mr. Diabetes" followed him down the road.
Mandell, who founded the nonprofit Defeat Diabetes, has trademarked the nickname "Mr. Diabetes." He wants people to associate that name with his face, and the motto "Awareness plus action equals prevention."
"I'm looking to become that barometer for diabetics all over the country," said Mandell, who was born and raised in Boston and speaks with an unmistakable accent.
Mandell was an athlete who created educational games for a living when was diagnosed with diabetes in 1985. He later started Defeat Diabetes with his brother. In 2000, he took the first step on his trip around the U.S.
He usually walks between five and six hours a day and has gone through 12 pairs of walking shoes in four years.
When he finally reaches the finish line, he hopes to have raised awareness for how healthful habits can prevent Type 2 diabetes, and the importance of early detection. He has visited with thousands of people and hands out free screening tests to nearly everyone he sees.
"Over half of diabetics don't even know they've got it," he said. "Diabetes can be eating at you for 10 years before it shows its ugly face."
Although his journey is nearly halfway complete, it has not been free of obstacles, including bad weather.
"We spent the winter in Las Vegas because we got up to the Montana-Idaho border and there was too much snow; it was too dangerous to walk in the break-down lanes," said Steve Hopf, who follows Mandell in the Land Rover.
In April, Mandell decided to try walking in Montana again.
"I came back figuring, it's springtime everywhere else, it has to be springtime in Montana," he said, laughing. "We lost 19 days in the month of May due to illness and weather."
Mandell plans to keep walking along Interstate 90 until he reaches Billings. To track his journey or learn more about Defeat Diabetes, log onto http://www.defeatdiabetes.org.