Chris Moyles has "an issue with body dysmorphia".
The Radio X DJ has shed more than 80lbs in recent years but still feels "really fat" and puts himself through gruelling workouts depending on how he feels about his size that day.
He said: "Before lockdown Monday, Wednesday, Friday I would do the show we would have a quick meeting...and then I'd get to the gym and I'd train 11 'till 12 or 11 'till one depending on how fat I was feeling.
"I'm feeling really fat at the moment. I'm fascinated by body dysmorphia because I really have an issue with body dysmorphia, which I think most people do.
"I've lost six stone from my worst weight when I was 18 stone 2."
The 46-year-old star weights himself almost every day and eats "very little" during the week to allow himself more pleasure at weekends.
He told Ross Kemp on his 'Kempcast' podcast: "I know my body really well now, and I'm still learning and I'm lucky that I have a trainer who is a real nerd about this stuff, he's got a very similar metabolism to me which is that of a JCB.
"I don't have the metabolism of an 18-year-old girl or boy, I just don't. I will, and people don't believe me, but I weight myself six days a week, and I know you shouldn't and I know it's not for everyone, but I do that so I can learn about how my body works.
"I will train Monday, Tuesday, Wednesday, Thursday, Friday and I will watch what I eat and I'll eat very little, I do intermittent fasting and I'll eat at half six or seven and I'll be fine.
"I need to do that from the weekends that I have."
Chris admitted relaxing his strict diet means he instantly gains huge amounts of weight due to "bloating".
He said: "I will be really good during the week and then Friday comes, I'll have a couple of drinks and then maybe Saturdays we will go for dinner and maybe a few drinks and then maybe Sunday we'll do something and I'll get on the scales on Monday and I will have put on anywhere from five, six, eight, ten pounds - ten pounds!
"It's not fat, it's just bloat, it's just water retention and by the Friday the next week that ten pounds will have gone and maybe a bit more if I've worked hard enough, maybe a little bit less, but it will go.
"By Friday I'll probably look exactly the same but I'll feel like 'yeah, feeling good'.
And the presenter finds it "boring" having to stick to such a strict eating regime.
He said: "I get to the weekend and you're f***ing tired and you want a drink, it's boring watching what you eat. Anyone who goes, 'I don't really worry about what I eat.'
"Well, you lucky bastards because I've got to."