A PERSONAL trainer who deliberately gained and then lost more than 30 kilograms so he could better understand his client says he was "humbled" by the experience.
Drew Manning, 30, stopped exercising and survived on a highly-processed diet of hamburgers, white bread desserts and soft drink for six months in order to empathise with his clients.
While the experiment was meant to explore the physical challenges, Mr Manning and his wife Lynn have told morning television in the US it also took a surprising emotional toll on their marriage.
Mrs Manning said her husband – who was usually helpful around the house and an attentive father to their two children – became lazy, moody, and lost confidence in himself.
“I was shocked because I really thought this was only going to be a physical transformation, that Drew was going to pack on the weight and lose it because it was 'on purpose'," she told Good Morning America.
“The hardest part for me is that he's so depressed, he's constantly complaining - he's jealous of me because I get to work out.”
Mr Manning said he didn’t realise how much he had changed until his wife pointed out his laziness and bad moods.
“I started snoring, I was chafing ... I had less energy so it did become exhausting and I could see how it affected our relationship because of that,” he said.