The Defence Forces have agreed to put the contestants on Operation Transformation through their paces in a rigorous Army boot camp for the first time on Irish television.
An elite group of expert physical instructors challenged the participants to take on the level of training expected by the Armed Forces.
"First of all, we put a group of our soldiers through the challenges," explained Captain Pat O'Connor. "Then we gave the contestants a toned down version. Military training is robust and robust means tough, hard and difficult. They will make you hurt, they might make you cry but they will challenge you," he told the Herald.
Captain O'Connor said that although the aim was to help the contestants to lose weight, it was also an exercise to teach them the value of operating as a team.
"The biggest insult in the Defence Forces is to be called a 'me feiner' so all of these challenges are about building up teamwork. We'll be trying to create a team out of the contestants.
"There'll be lots of tough love, particularly from one instructor," he added. "It encourages people to keep pushing themselves, don't just wimp out."
On tonight's episode, it's revealed how the team managed to lose the weight.
Cork bride-to-be Amanda Casey (28) shed an astounding 10 and a half pounds as revealed on the daily updates on the Gerry Ryan Show on 2FM.
"They all exceeded their expected targeted weight loss," a spokesperson for RTE said. "It's due to a complete diet change and lifestyle overhaul."
This is the first time the Defence Forces have been called to assist on a national television show.
"If we can help in the fight against obesity, we are happy to do it," Captain O'Connor said. "First of all it shows off what our soldiers can do and then we can see the level expected these are expert in physical terms."
The five have been whittled down from 20 hopefuls who are aiming to shape up and lose weight in 2010 with the help of fitness guru Karl Henry, weight loss expert Dr Eva Orsmond, psychologist Dr Eddie Murphy and motivational coach Enda Mc Nulty.