BBC newsreader Huw Edwards said he has undergone a physical and mental "transformation" since taking up boxing training.
Mr Edwards, 58, who is from south Wales, has been training with former professional boxer Clinton McKenzie in a bid to get in shape.
He spoke about his weight loss in an interview with BBC Radio Cymru.
"The truth is that I lost weight because I felt unhealthy. It's simple enough," he said.
"I was physically and mentally in the wrong place. I was far too heavy and I wasn't happy with that. I wasn't happy with my own appearance, and I realised that I wasn't being fair with my own body in terms of my general health and wellbeing.
"I just felt pretty low to be honest, and it got progressively worse. Losing weight and getting fit have been a transformation for me."
He added: "The issue of image can be a nuisance because the newspapers write all kinds of nonsense about it.
"Where I enjoyed my boxing training, and used social media to promote it, this attracted a fair share of snarky comments in the press.
"I've also learnt that being physically fit means one's mind is sharper, and one's mind is healthier. To me, that has been an eye-opener. I feel far better now than I did in my 30s and 40s.
"I suppose my message to anyone in their 50s - male or female - faced with a similar situation to mine and feeling low, is that making the effort to get physically fit will pay huge dividends both physically and mentally.
"If I can do it, anyone can. I just hope that my journey can inspire others to do the same and improve their lives."