The Irishman has lost a couple bands around the waistline and is playing his best football since his days at Nottingham Forest.
"I didn't wake up one morning and say, 'I am going to do this'," Reid explained to the Daily Mail.
"It was something I felt I wanted to do and I needed to do. I spoke to the chairman about it and he felt it would be a good idea, which would benefit me and the club. So I went away and did it.
"Towards the end of last season, things were not going particularly well at the club for myself or for anyone else, for that matter. I just felt I wanted to have a good summer and give myself a good opportunity when we came back.
"Everyone knew there would be a new manager coming in and we all wanted to make a good impression and I was no different.
"So I had a break straight after the season, which I enjoyed. It was not a big blast, I just chilled out, took a complete break for two weeks and didn't do anything, which I felt was important, not so much physically as mentally. It was a very long, grinding season and I needed to re-charge and get my head round coming back and putting in a good shift in the summer and doing some hard work.
"Initially, the idea was not to lose weight, it was more to get fit. But, as I started to feel and get fitter, I started to lose weight and it continued from there. I was consciously looking after myself better, I was watching what I was eating and drinking and the times I was doing it.
"I was conscious the weight was coming off but I was more conscious of the work and making sure I was working hard. The great thing was that it was really enjoyable."