The programme made gains of 36,600 viewers from last year's first episode to reach 594,800.
"Last year's season was more popular than any other year and it looks like it will be heading this way again in 2012," an insider told the Herald.
"Presenter Kathryn Thomas has been a great addition to the team, she's really enthusiastic about the show and supportive of the leaders so it translates really well on screen.
"The fact that Operation Transformation has really taken off on Facebook also means that it's become a lot more accessible, viewers are sharing tips.
"There's a whole Operation Transformation community out there supporting one another and organising their own fitness challenges -- which is the way it should be for successful weight loss."
Members of the public were encouraged to follow the participant who had the most similar lifestyle to them, so they could then follow the leaders' new regime and progress.
Nutritional and exercise advice was posted on RTE's Operation Transformation website to this aim, attracting an even bigger crowd of internet users than last year.
In 2011, the programme's interactive site had an impressive 326,957 page views a day after the first episode was aired, while this year the figure has gone up to 397,116.
A site dedicated to mobile phone users was introduced this year so the show's fans could set up their own Operation Transformation profile.
Myot.ie allows viewers whose Body Mass Index (BMI) is above the recommended 18 to 25 range, to follow the progress of their own diets and to set weight targets.
Meanwhile, speculation that this year's series will have a six-month follow-up episode is rife.
"The follow-up episode was a first last year and it worked really well so there may be another one this year," a TV insider told the Herald.
"Viewers want to follow the leaders all the way -- it's not just about watching the programme, cooking Dr Eva's recipes or doing Karl Henry's exercises for seven weeks only.
"It's about a long-term life change, and one way of keeping motivated is to know that the leaders have kept up their new routines, that they have managed to overcome their health concerns thanks to the show's advice."