Dear Body, Queen Elizabeth Hall, London<br>Nowhere and Everywhere at the Same Time, Tate Modern, London

Body-dissatisfaction used to be the preserve of teenage girls. Now everyone is at it, as the beauty and style industries, not to mention TV makeover shows, cosmetic surgery practices and "personal trainers" combine to persuade us that there is no square inch of flesh that can't be toned, tweaked or generally improved on.

The psychotherapist Susie Orbach has publicly bewailed the self-loathing this induces, particularly in women. And now a dance company called Protein has weighed in with a satire on body fascism. Dear Body strikes a blow for every perfectly healthy person who has ever looked in a full-length mirror and felt bad.

Directed by Luca Silvestrini, the piece follows a team of snarling professional gym-bunnies as they wrench, pummel and kick-box their way to physical perfection, terrorising their clients in the process. They include Sarah Storer's spike-heeled aerobics sadist, who launches into furiously complicated routines that the class can't possibly follow. There's preening, queeny Nuno Silva, who can't enter a room without showing off his latest variation on the benchpress, red-haired Michael Spenceley, who seeks to assuage his ginger hang-up in increasingly violent massage ("I can feel it working!"), and David Lloyd, whose manic workout culminates in self-strangulation. The team is completed by Vicki Manderson's sunny nutritionist who counsels that "happy stools are eight to 10 inches long".

Into this self-regarding Bedlam wanders Sally Marie, a homely specimen with cellulite thighs and an innocent desire for self-improvement. "I'm doing the A-Z of change," she tells us. "I've done abs attack, aromatic cross country, absolute yoga ...."

The warm heart of Dear Body lies with this excellent dance-actress's comic timing, and – damn it all – her nerve, as she strips down to her sensible bra and beige knickers and surrenders to the inevitable humiliations. These include not only the obvious (but still funny) failed attempts in class, but also failed attempts to keep her fingers out of the Nutella jar (the Nutella's for facial massage), and her breasts from wobbling in a jolly bouncing session with exercise balls. Only halfway through does she notice that everyone else has kept their bra on – the stuff of classic nightmare.

It's a shame that some of the group sequences are a little too long and unfocused, and clever visual effects using Cellophane lose impact through repetition, but overall, Silvestrini's frenetic cartoon style finds its target. When our misguided self-improver emerges from surgery gamely tottering in high heels, mummified in bandages and minus a kidney ("They said it was weighing me down"), there is real pathos in her declaration that she feels, at last, ready to be loved.

The Focus on Forsythe season rolled on last week with an event in Tate Modern's Turbine Hall. But unlike previous expositions of dance in that vast space, in which the work took on some of the heroic scale of its surroundings, William Forsythe's offering looked puny. Nowhere and Everywhere at the Same Time – a title whose relevance became no clearer – involved a dozen or more of Forsythe's dancers negotiating paths between 200 small steel weights hanging at regular intervals from 70ft strings. Spectators sat on cushions around the perimeter, respectfully hushed, as a score that sounded like plumbing problems burped and rumbled, and performers in jeans and T-shirts crept about looking demented.

For me, the sea of pendulums was just about worth seeing, glinting in the evening sun, forever in faint motion, almost as if it was alive. However, an hour and a half is a long time for contemplation. Clearly there were rules to the game Forsythe was playing, but trying to decipher them was futile.