In 2003 Sid Lerner, a successful ad agency executive, discovered he needed to take medication to lower his cholesterol level and started exploring how to make a meaningful difference in not only his own health but also the nation’s health. He asked nutrition experts at the John Hopkins Bloomberg School of Public Health how much saturated fat should be removed from a diet to make a meaningful difference in health, and the answer he received was 15 percent — just one day’s intake.

And that was the inspiration behind Meatless Monday: Giving up meat for just one day can help save lives and prevent or delay heart disease and cancer.

Launched in 2003, there are now tens of thousands of schools, restaurants and foodservice companies participating in Meatless Monday in 23 countries around the world. The campaign started in the U.S., then gained traction globally when Paul McCartney launched the campaign in the UK in 2009. Australia and Israel launched the initiative last year.

Health advocates and celebrities, including Oprah, Virgin Atlantic tycoon Richard Branson, Yoko Ono, Kate Moss, Robin Roberts of “Good Morning America,” and “The Biggest Loser” trainer Bob Harper, have all expressed their commitment to the Meatless Monday initiative.

Peggy Neu, director of the Meatless Monday campaign, said the program is growing tremendously. “Our research shows that nearly one in five Americans participates and avoids meat on Monday at least occasionally. It plays into the vegetarian and ‘flexitarian’ trends,” she noted.

Why Monday? “Monday has special significance as the beginning of the week. People view Monday as a day for a fresh start and a chance to set healthy intentions,” explained Neu. “Google searches for the word ‘healthy’ soar on Mondays as compared to any other day of the week.”

Neu and her team are actively recruiting restaurants to promote Meatless Monday menu choices. “It is becoming a positive trend, and chefs and their guests are jumping on board,” she said. “In fact, we have restaurants telling us that their Meatless Monday choices are enticing people to dine out on Monday, and sometimes it is a whole new clientele. It’s easy to do and a celebration of alternatives that focus on fresh, local and seasonal produce.”