I am working out in the gym at the top of my apartment building in downtown Los Angeles and trying not to stare at the men around me. This is rarely a problem for me. With the best will in the world, few of the men at my regular gym in south London are sparkling physical specimens you would want to spend much time staring at. I include myself among their number. I am the number one man you do not want to look at, or if you do look, you want to look away again quickly without grimacing too obviously. We are ordinary blokes, fighting the unavoidable calculus of biology and the passage of time. We are doing what we can, and it ain't pretty.

Which is what's so different here in LA. Everyone is pretty. Even the ugly men are pretty. They have a chiselled, muscle-cut six-pack and pectoral grandeur to them. And don't even get me started on the women, those lithe, caramel-tanned, spun-sugar-haired creatures with their size-zero figures and gravity-defying busts and lilo-pumped lips and arses. Not that the women are the issue. I've been coming to LA for years and have got used to the way the women look here. It's like visiting the Lake District and enjoying the blissful views without being startled by them.

This time it really is the men who have got my attention. I want to know if I measure up. Or to be more exact, I want to know how far short of them I fall. The fact is I have become worryingly obsessed with body image, namely my own. This was never an issue when I was solely a print journalist. To borrow the joke about politics, print journalism is show business for ugly people. Or to put it another way, none of us ever gets hired because of how we look and thank god for that or a lot of us would be out of a job. Unfortunately, I have stumbled into television. This is my own fault, a product of my low boredom threshold and my shameful desire to show off. Suddenly I have to give a damn about how I look, not necessarily because I actually care – though I do – but because you can be sure others will have a view on the subject too.

There are two ways to deal with this. I could either get off the television or stay in television and become obsessed with how I look. It appears I have chosen the latter, for I am here in Los Angeles for a month doing what every British person in Los Angeles does these days. I am The British Reality TV Show Judge. I am working on a show called Top Chef Masters, in which big-name celebrity chefs from across the US compete for the title. My job is to eat their food and say witty off-the-cuff things about it on camera, in a wry British flat-vowel-led way.

Top Chef Masters is shot on a specially built set in downtown LA, costs hundreds of thousands of dollars an hour and generally involves eight – count them, eight – cameras, all of them high definition. And oh, isn't that technology kind to the ragged complexion of a 43-year-old London bloke who has seen too many pies in his time?

So I regard my obsession with my body image less as some weird, pathological condition than as an entirely reasonable response to the circumstances in which I find myself. That is exactly what I tell myself as I bash away in the gym, looking at the beautiful men and wondering what I must do to become one of them. After all, here I am in the beauty capital of the world, ground zero for the cosmetic-surgery business. Everything I need is to hand. What would it take to turn Brixton man into LA man? I mean, if these ordinary guys can do it, why the hell can't I?

My first stop is Kalologie, a beauty clinic on Ventura Boulevard. A lovely nurse of Philippine extraction called May Lazo takes me out for coffee to discuss the various procedures available. She sips her skinny soya latte and tells me that my impression that Los Angeles is the most body-obsessed city in the world is not wrong. "I have this saying: fat for Los Angeles, thin for Chicago. In other words what's considered heavy here is thin anywhere else in America. It really doesn't take long to become obsessed with how you look here." She whispers that all her colleagues at Kalologie are equally obsessed.

Mostly she administers Botox and fillers. I ask her what she would do to my face. She peers at me. "Well, if it was my personal preference I wouldn't have you do anything." That's very sweet of you, May, but it's a jungle out there. The streets are thronging with Greek gods. Let's get real. "OK then, I would deal with the lines around the eyes," she says. "A little filler there." Now she's warming up. "Maybe some more on the nasal labial fold." What? The two creases between mouth and nostrils? "That's it. And I'm looking at the redness of your skin." What redness? I wasn't aware of any redness. "The redness that I'm looking at is caused by blood vessels close to the surface. I would use intense pulse light. The light translates into heat and that heats the blood, which bursts the blood vessels, and away they go." I point out that I have to be on camera the next day and she looks a little disappointed. "Oh, we shouldn't do it then. There can be swelling."

She suggests instead a $90 facial. "The number of men coming for these treatments really is on the increase. A few years ago they were put off because the clinics were too feminine, but now they are more neutral." She also says men can be more sensitive to pain. "They are more afraid of pain." This doesn't seem unreasonable, I say. Pain is worth being afraid of. I am introduced to Jamie, who lays me down and steams open my pores. She covers me with me an antibacterial pore decongestant, exfoliates me and conducts what she calls "minor extractions" – she squeezes my blackheads (the things people will do for money) – gives me a facial massage and a seaweed mask with an antioxidant serum and then covers me with a cream containing hyaluronic acid which apparently hydrates from within. Afterwards I feel fabulous; 24 hours later, however, my skin starts to peel off.

After my facial I go to see Anastasia Soare, eyebrow lady to the stars. Anastasia has done Jennifer Lopez for years, has plucked Sharon Stone and Madonna, Donald Sutherland and Colin Farrell (she once described herself to friends as a total star plucker). She even went to work on Gabriel Byrne's brows and they were so thick small children could have got lost in them.

Anastasia, a handsome, slender woman with lovely fine, fully separated eyebrows, was born in Romania and came to the US in the late 80s. She still has a thick accent. She describes her story as the American dream come true. She trained originally at art school; she says it was because of this understanding of classical sculpture and the work of Leonardo da Vinci that she came to recognise the importance of eyebrows. "By shaping correctly the eyebrows you bring everything else into balance," she says. "It is the golden proportion. People are drawn to you, but they don't know why." So how does she do this? "I tweeze, I wax and I cut."

I ask her what kind of eyebrows a man should have. "A man should not have very arched eyebrows. The space between the eyebrows should be smaller than on a woman. The noses of men are bigger than the noses of women. If the space is too big, the nose becomes too prominent." What would she do with mine? Normally, like the facial, this costs $90. "First of all I will dye them." I open my mouth to say something, but she gives me a hand mirror. "You have very dark hair, but your eyebrows are too light. When I dye your eyebrows your eyes will look twice as big." It occurs to me that I will also look like David Gest.

I bark "continuity issues". This TV show I'm working on is actually proving to be my saviour. Anastasia looks crestfallen, and begs me to call her the moment the filming is finished. "Then I dye your eyebrows." I promise to do so.

I need to go hardcore, which obviously means one thing: liposuction. The king of liposuction is a tidy Hungarian émigré called Dr Peter Fodor, who wears sports jackets and eyelids that speak of a little work. He has twice been president of the Lipoplasty Society of North America and is unabashed in his enthusiasm for the procedure. "Isolated deposits of fat may be very difficult to remove through exercise or diet," he says. "And yet people continue to diet until they become gaunt. Still the problem area is not dealt with. Liposuction can deal with that."

Why did he choose it as a discipline? Partly, he says, because of the skills involved. "It is more creative. It requires an aesthetic sense. I even etch abdominal six-packs." But also, he argues, it is because it is one of the few medical disciplines where the outcome is always positive. "You operate and save a life, and that is a positive, but only in the sense that you return a life to normal. With what I do we take people to a new place in their lives." Proudly he shows me before-and-after slides, endless pictures of sagging stomachs tautened, of love handles vanquished and thighs sculpted.

He takes me to an examination room and I strip down to my underpants. A couple of years ago, in an attempt to conquer a lifetime of fat, I embarked on a gym regime that shifted almost 4 stone. There is definition to my shoulders now and a chest of which I'm proud, but there is still a belly and love handles whole families could cling to. I do not feel comfortable with this body of mine, even less so when it is positioned before a hinged mirror for a three-sided view. Dr Fodor gently squeezes my folds. "I would suggest suction on the love handles first. Then later we would do liposuction and a tummy tuck combined, and finally we would come back and do a little more lipo to tidy up." He can remove 5kg of fat at one go. I am gutted (or would be if I let him have his way). I had thought that I had made great strides, but clearly there is so much more to do.

The fact is, I am a complete coward. I've said no thanks to light pulse treatments and black eyebrows and a definite sod-off to lipo. At the beginning I asked: why can't I be like all those other boys in LA? The answer: because I haven't got the stomach for it (even though the stomach is the problem). I am not committed enough. I am not yet certifiable. There is only one thing I understand, and that's the gym. I make an appointment to see Jackie Warner, personal trainer to the stars and a celebrity in her own right. She is blonde and taut and very gay. Her own cable reality show, Work Out, was as much about her lesbian relationships as it was about her route to perfect abs.

Normally she costs $300 an hour. We talk briefly in her penthouse gym overlooking Wilshire Boulevard about celebrity culture in LA. "This town is where it all comes from," she says. "Everything that's ever read about in the celebrity magazines, it comes from here. People like me have to be careful about the messages we put out." Right now the film stars up in their Hollywood Hills villas are using "cleansers" to get thin. "So dangerous. Maybe it contains water, lime juice, a bit of maple syrup, stuff like that. And that's all you're meant to drink for 10 days."

She believes in the workout, much as the Pope believes in God. Normally I get on a cross trainer and pump away for 40 minutes and think pointless airy thoughts while I'm doing it. No good, she says. My body has plateau-ed. It's used to it. I need to do something radical and varied. She makes me bench-press weights, and follow that with press-ups. Next I have to push hunks of iron with my feet before doing the ugliest, most ungracious jumps I have ever done, my shirt rising up to reveal the belly the good doctor was thinking about sucking out only an hour or so before. She makes me do all that three times. She puts me on a treadmill and forces me to walk up a steep hill and then to run. Sweat pours off my head. Snot dribbles over my moustache. I am human wreckage. And all the time the nice, scary blonde lady is barking at me to keep going, to do more, to move on.

We finish. I say thank you, much as a hostage in the advance stages of Stockholm syndrome might thank their kidnappers for being so kind as to have imprisoned them. I can't pretend any more. Whatever efforts I have made with my physique, I still distrust its folds and creases and wobbles so much that the idea of working on it with anyone else is horrifying. I prefer to shove on headphones, fill my ears with music and pretend no one else is in the room. Plus, I hurt. I really hurt.

I walk on to the rooftop to cool down and look out over Los Angeles, at the streets teeming with beautiful physical specimens. I think of all the eyebrows dyed and all the skin tightened and all the fat sucked out, and all of a sudden I feel terribly terribly weary and terribly, terribly old and I know exactly what I have to do. I have to go home.