Ana came for me when my sister died.

I was fourteen when Mia left us and the whole awful thing made no sense to me. She'd always been healthy, happy, bright as a sunflower. She danced. She adored dance. Even after she was rejected from the ballet school she still danced in her room- more so, in fact, her eyes shut so that she could fully savour the experience. She jogged every day before school and nibbled fruit while I lounged in my room and enjoyed light, fluffy angel cake, heavenly milk chocolate and gallons of fizzy, frothing cola. God, was I greedy! But I was healthy, somehow. Fat, bursting with greasy gunge like an acne spot, but healthy enough to feel fine- healthy enough to survive.

The worst bit was that she didn't leave all at once. Death was sneaky; he stole her bit by bit, ounce by ounce. She shivered. Her hair lost its shine. The muscles holding her smile in place wore away. Her eyes, her bright, clever eyes, flitted when you talked to her, her glance ricocheting around the room, never settling on one place. I used to hear her talking in her room, but when I went in to see who was there she was always alone. I should have stayed and talked to her myself.

Standing by the coffin, all I wanted to do was crawl in with her. She looked… This sounds awful, but after all those months of drifting to death, she looked better. Her soft, tanned skin had faded to a pale, sepia tone like an old photograph, and someone had painted her face tenderly. Around her neck was the cheap, grey, lace collar she'd took to wearing just after the ballet place rejected her.(We thought it was the start of another phase. Once she dyed her hair lilac and threaded little gold beads into her braids.) The undertaker had slipped a little bundle of forget-me-nots into her hand. She looked so happy. Relieved. Was it that bad she couldn't wait to get away?

What idiot decided that open caskets were a good idea? I wasn't thick; I didn't expect her to jump out of the bloody thing and yell, 'Surprise!' I shut my eyes. It wasn't her now, anyway. I kissed her forehead- she was cold as cod.

Someone tapped me on the shoulder the next day as I was walking. The frozen fingertip made me squeak.

'Jenny, isn't it? Such a sweet name.'

To be completely honest, I wouldn't have stopped if she hadn't looked like Mia. Both were as slim as daffodil stems. Both had beautiful bone structure. Both had long, dark hair. Had the girl in front of me not been paler than a ghost, I'd have been sure it was Mia.

'Who are you?'

'Well aren't you polite?' She smiled, of all things. 'I knew your sister. Sorry about that.'

Everyone's always sorry.

'It's fine,' I fibbed, my eyes dropping to my muddy, blue trainers. 'I'm sorry, I didn't ask your name.'

'Ana.' She noticed my frown. 'She didn't like to talk about me, if you don't recognise the name. I took her jogging.' Tucking her hair behind her ear, she leaned her head forward a bit to stare at me. Her eyes were bilberry blue just like my sister's- just like mine. 'You look a little like her.'

I had to laugh at that. There was about as much resemblance between Mia and me as there was between a hummingbird and a fried egg.

'She was a lot prettier,' I mumbled.

'You've got have the same cheekbones if you look hard enough. Hmm.' Her brow creased in (false) concentration as she patted my round tummy. 'Have you thought about losing weight? It'd make your bone structure more obvious.'

My overbite sunk into my bottom lip. Was it me, or was this girl being a little bit rude? It did sound tempting, though, looking more like Mia. Maybe we were identical beneath the flab. Maybe then I'd still be able to see her as she was, lively and lovely, like she'd been before she was ill. I could remember her without the forget-me-nots, without the dead smile.

Ana's smile glinted to show small, sharp, white teeth.

'Come with me tomorrow, if you like. You can come jogging with me.'

Let me tell you, I'd had no idea how out of shape I was until I was puffing and panting, my skin poppy-red and prickling with heat. A few feet ahead Ana giggled at me, her feet springing along the pavement, oblivious to the cold. Her white legs glowed in the dark.

'This burns three hundred calories an hour, you know. You'd be surprised how easily it goes down,' she chirped, cackling like a poltergeist. 'Two hours a day, that's six hundred calories. Two hours a day for a week is four thousand two hundred calories! And there's three thousand five hundred calories in a pound.'

'It's hard work,' I gasped, dropping onto a bench. Instinctively I reached into my pocket and grabbed a packet of chocolate buttons I'd bought the day before. Regaining my breath, I caught the packet between two teeth and pulled the plastic packaging apart. Shutting my eyes, I shut my eyes and inhaled the sweet, warm smell until a second later the skin of my arm crisped under Ana's spectre-white hand. 'What?'

The look she gave me could've drawn blood.

'Do you have any idea what's in that?' she asked me, her eyebrows jumping up to hide under her fringe. 'Filth. Fat and sugar and all sorts of muck.'

'It's only a little packet…' I bit my lip.

'That little packet is worth a half-hour of jogging. You might as well've not come if you're going to stuff yourself afterwards.'


'Honestly, it's no wonder you're so huge.'

My teeth pierced my bottom lip. Hunching my shoulders, I let the packet fall out of my hand- the hot, oily taste of blood quickly killed my appetite. No sooner had the packet hit the pavement than Ana swooped down, grabbed the packet, and tipped it upside-down. Then, once the buttons had rolled off into sewer grates, she shoved the packet back into my pocket.

'It's best if you keep them,' she explained. 'It helps you remember to keep away from them. Cake's even worse, and bread. Anyway, are you coming tomorrow? We could go through the park if you want.'

Eventually- when I learned to catch my breath- we used to talk about Mia; well, I did. I told her memories of us being little, the time she'd tried and failed to teach me a dance, the songs she used to like, how she always bit her nails, how she painted her bedroom wall to look like a rainbow, how she put a lock on her bedroom door without telling Mum, her smile at the funeral, how much I missed her. For the most part Ana just listened, jogging along with a straight mouth and her eyes ahead, charging ahead even as I got faster. Calories, calories, calories.

'Do you like green tea? It helps boost your metabolism.'

'Keep a food diary. Realising how much you eat will motivate you.'

'Eat in front of a mirror so you won't eat too much.'

'Only two pounds? Have a cold bath when you get in- as cold as you can stand. Your metabolism will work faster.'

'Are you really going to eat that?'

'Punch yourself in the stomach and that'll stop you feeling hungry. Here.' (I had a bruise for three days after.)

After I lost the two stone in five months Ana gave me a present. The necklace was a kind of choker made of shimmery-grey lace embroidered with silver beads. She fastened it for me while I held my hair up.

'You should take better condition of your hair, you know, or people will start to suspect something. What weight are you now?'

'Eight stone three, apparently.' I squeezed my leg, watching as fat enveloped my fingers. 'My scales might be broken. I still feel huge.'

'You'll feel happier when you lose a bit more. What have you eaten today?'

'An apple for breakfast, then a chicken salad for lunch.'

'Try cutting out meat. Just tell your mum you want to be a vegetarian or something. That's what I told mine.'

Nodding, I turned the top of my smoothie. My stomach groaned.

'You don't want to eat that.'

'Why not?'

'Your metabolism starts slowing down after two stone. You need to eat less if you want to keep losing weight.'

'I'm not eating much anyway.'

'Urgh.' Rolling her eyes, she shot her hand down the back of my collar and yanked. Spluttering like hot soup I dropped the bottle in surprise.

'What did you do that for?'

'I told you, idiot,' she snapped. 'I told you that you need to eat less now and you aren't listening! Now look what you've made me do.' She pinched the back of neck and twisted the skin sharply, digging her nails in; I yelped.

'I'm sorry!'

'No you aren't,' she sneered. 'You're such a weakling. You've got no self-control at all, have you? Have you?'

'No,' I whimpered, my face burning hotter than an oven. If there's a Hell, I was in it for those five second, my whole body scorching enough that I'm surprise my tears didn't evaporate.

'Oh, stop blubbering. Do you want to get fat again?' Finally letting go, she sat down beside me and very gently curled her arm around my waist. My big, blubbery waist. 'I'm doing this for your own good, you know,' she mumbled, stroking the side of my arm. 'There, there, no need to cry. I'll look after you.'

From then on she went everywhere I did. Whatever passed my lips went down on paper:

2 carrots (52 cals)

4 glasses of water

10 raspberries (24 cals)

Total: 76 cals

She always hid behind the door when Mum came in wondering who I was talking to.

'I was just on the phone.'

'All right, darling,' she'd smile before slipping out. She barely spoke anymore. 'Dinner's downstairs, are you coming?'

'Actually, I don't feel all that hungry,' I said, watching Ana mouth the words. Yes I did. 'I already ate at a friend's house.' No I didn't.

'Oh… Sweetheart, is something bothering you?' she asked, shutting the door behind her. 'We barely see you anymore.'

My heart threw itself against my ribcage like a lunatic against a padded wall. My eyes ricocheted around the room. She knew. She had to know. She didn't say she knew, but we both knew she knew. And Ana knew she knew.

'Fine, Jenny. You're fine,' she hissed, her eyes manic and bright with panic.

'I'm fine.'

'Oh,' Mum said. She lowered her head. 'Well, your dinner's downstairs on the table if you change your mind. You… You would tell me if something was wrong, wouldn't you? It's good that you want to be healthy, but-'

'I'm fine,' I cut in, and I clamped my lips together as I hurried to the door. 'I'll eat it later,' I lied, focusing on the white door frame. I couldn't have said it looking at her. 'Love you.'

She sighed. I hadn't fooled myself and I didn't fool her.

'Love you too.' She trudged back out into the hallway. Shutting the door, I jerked my head around to look at Ana.

'She knows.'

'No she doesn't.'

'You could see it on her face. Oh God…' I started to shake and stumbled back onto my bed. My brain whirred. 'I don't feel very well, Ana.'

'Calm down,' she soothed, though her voice kept its hard, bony undertone. 'Let's go for a run.'

'Not another, please.' My stomach howling, burning as though it had finally started to devour itself. 'I need something to eat.'

'No,' she ordered. 'You're so close. You can't start gorging yourself now.'

'I don't care,' I groaned, clutching my stomach. Clinging to the bedpost I limped to my door.

'Don't you dare.'

'I can't do this!'

'You aren't trying hard enough,' she accused, stepping back to stand by the mirror in the corner. 'Pathetic. Look at yourself!' Before I could turn she hooked a finger into my grey collar and dragged me forward, almost pressing my nose against the mirror. 'Look!'

The reflection gasped as I did, lips pale against her sickly skin. Beneath her morsels of flesh her poor little bones jutted out like the bars of a birdcage. She was as frail and pale as Mia in her coffin.

I had my wish, and it terrified me.

'Can't you see that I'm trying to help you?' Ana yelled, her voice venomous. 'You're going to get fatter, you know. If you don't do something, you're going to get worse and worse!'

'Oh God!'

Before I realised I'd done it my hand connected with her cheek; her fragile frame slapped against the floor and I staggered out of the room, clinging to whatever I could grab until I fell into my chair at the dinner table.

Stew- Mia's favourite (though eventually she wouldn't even eat that). Just vegetables- Mia was a vegetarian. I never liked it- the brown gunk reminded me of rot. Slowly, reluctantly, I lowered it into the brains-and-remains vegetable soup. I lifted it up. I opened my lips. I closed my mouth around the spoon. The potato was soft in my mouth, squishy like an eyeball. Ana dropped to the floor, mewling like a dying animal. My stomach's pleading grew quiet. My collar fell into my lap.

I did it again, and again, and again.