On entering Farmacy in Westbourne Grove, I immediately feel as though I have shrunk and swollen into the incarnation of Roz, my fugly avatar on Twitter. The whole place is populated by creatures of luminous beauty, long and slender of limb, glowing of skin, sheeny-shiny of hair. Here they are, the disciples of “clean eating”.

The clean-eating trend (cult? epidemic?) is spawning temples of worship like kombucha spores. Deliciously Ella with her Mae “delis” (although she has now, in a slightly panicky way, distanced herself from the word “clean”); M Raw, “London’s first 100% gluten-free fine dining restaurant”; Vita Mojo, which promises to “put you in control of your diet”; the Detox Kitchen; Rawligion; and too many more.

The same day I visit Farmacy, I eat roast broccoli at Counter Kitchen that costs £8, and a small bottle of wan, cucumbery green juice for nearly a fiver. I call by Redemption in Old Street, east London (sugar-free, wheat-free, alcohol-free), where the lovely young guy at the bar trills, “Are you a vegan?’ with the fervour of a Moonie. But my main event is this glittering, plant-filled restaurant from Camilla Fayed, daughter of Mohammed Al, in west London, clean eating’s spiritual home. It is clearly an absolute smash, but I pray I never have to eat here again.

It’s “healthy choice comfort foods”, we’re told, so there’s a “sourdough” pizza with all the personality of an inflated Ryvita topped with spurts of lurid vegan cheese looking and smelling like burst boils. There’s a burger, a leaden wad of compressed black fibre that lives in the mouth long after swallowing. (Nice sweet potato fries, though.) And “Earth Bowls”, a key part of the trend, random items flung into bowls so they can be chugged with spoons. The infantilism.

In what’s something of a portent, ingredients are repeated all over the place: the frijoles, salsa, guacamole and “sour cream” (grouty stuff made from nuts) that feature in a plate of nachos also turn up in the Mexican bowl; ditto the meze – clunky, pasty sweet potato patties (“falafel”? Hmm), baba ganoush, soggy quinoa with a gummy drool of something non-dairy glueing it together, zatar (sic) crackers – as well as the Middle Eastern version. Flavours are muddy, textures claggy, thrills few and far between.

Perhaps desserts will perk us up? A vast, Instagram-worthy sundae, a “Berry Mess” of mostly blueberries, “cream” and “coconut nice cream” with, lurking in its depths, dusty shards of “maple meringue” (made of, I dunno, actual dust?) coats the palate with a gritty, fatty deposit. “Raw chocolate tart” brings more “coconut nice cream” and squares of brown material dense enough to lag lofts, a stodgy penance.

“No wonder they’re all so thin,” hisses the pal. Our bill, with the cheapest wine and one (good) cocktail each, is £120 for two. Those nachos alone are 12 quid. Oh, and I have a “Farmaceutical syringe shot” – an actual syringe filled with a thimbleful of, among other things, gotu kola and garcinia – for five quid. Might also feature sucka.

Photograph: Karen Robinson/The Guardian

Beautiful restaurant, lovely staff, horrible, bullshit food. As ever, just my opinion: Farmacy’s customers are loving it, buying it hook, line and silica – we wait nearly an hour for a table on a week night. Do I think slender beauty comes from necking “adaptogenic lattes” of reishi, chaga, maca, whateva? I do not. Had I been weaned on the stuff, I still wouldn’t manage willowy: my Italian-Irish peasant heritage has put paid to that. “Eat like me and look like me” is the goddesses of clean-eating’s message, omitting to mention good genes, loads of money and bags of privilege. I’m not writing this as a bitter old hag, but as the mother of a teenage girl; it makes me mad, especially when I suspect that “Berry mess” had more calories, sugars and fats than Big Mac plus McFlurry. (I haven’t the space to rant properly here, but The Angry Chef blog is righteous on the subject.)

But wait: the morning after my day with the clean eaters, I have an unexpected lightness to my step. Positively jet-propelled. I couldn’t say whether this diet will make you foxy, but it sure as hell ain’t going to make you fragrant. “Our offer is founded on… learning to listen to our inner selves,” waffles the Farmacy website. Here’s what my inner self is saying: “Parp!”

• Farmacy 74 Westbourne Grove, London W2, 020-7221 0705. Open Mon-Sat, 9am-11pm. Sun 10am-7pm. About £40 a head, plus drinks and service.

Food 3/10

Atmosphere 8/10

Value for money 1/10