You say you want to overhaul your life, and that this time the New Year's resolution is going to stick. You want to be fitter, trimmer and happier, and you think all you need to do is turn up for sessions three times a week.

There's so much more to it. I don't want to stamp on your dreams, but at some point I must come clean. I can't fix you. I'm not a qualified therapist and know nothing about corporate finance. I can only help you feel better about yourself. And I've told you 100 times that five glasses of wine rather negates the effect of sessions. (Yes, I can smell it on your breath.)

It doesn't matter what I'm feeling. All that matters is you and your body. It'll be the same for the next person, and the next. I've got the lawyer at 8am – he likes to train in luminous leggings, listening to the Pogues. Who am I to judge? He's lost 8% body fat in three months, after all. Then there's the dentist, so sweet, but full of hatred for her body. How long will she stick at it this time? Last time it was a month before work and children meant she could no longer find two hours a week for herself.

Last week, an actor's agent cried on me mid-squat. She works until 3am four nights a week, but says the training's the problem – it's eating into her sleep and she has to stop. Yeah, right, I think: the training is the only thing that keeps you from cracking up. But I stay quiet.

Truth is, they tell me everything, but they never listen. And it's not my place to interfere. I shouldn't care so much. That's my weakness.

• Tell us what you're really thinking – email mind@theguardian.com