Parent of three daughters here.

As Becky said bullying is something to look out for.

Also carefully and subtlety keep an hour in her eating make sure she isn't skipping meals or leaving the table straight after meals. This is from experiences of a friends daughter. Don't make food an issue though.

We do a thing at family meal times called question of the day first everyone says one good thing about their day and one bad. Then one persons asks a question like what is your fav song or what animal would you like to be. Its just a good way of starting a conversation you will be surprised what you might find.

Finally all kids are different some hide in their rooms and some join every club going. But treat them all the same and dont compare them. I expect it's just one of those phases. Be supportive. You will come out the other end.

The fact that you are concerned shows good parenting.

Show a United front even if you disagree with your with your partner. Discuss it away from the kids

Probably been no help at all but best I have.

Good luck

Tom,

Basically you're screwed mate.
I have 3 daughters now 21, 30 & 34.
The 21 yr old still lives with me & still does moody, although shes been no real trouble.
The older 2 however both went from moody kids to getting on the piss and clubbing, bringing back w***ered mates who chundered the house up.
Then theres the having to fetch the sods from outer Mongolia in the early hours because they've got ill, upset or skint.
dont forget at 14 shes just getting interested in fellas so youll have lads with only one thing on their minds rocking up to take them out over the next few years.
some will bore the s***e out of you & try to be friendly.
blank 'em.
I reckon you got a 10 year session of hassle.

very true, it's not just hormones the world and all its depressing aspects hit us in the face around this age, this is often underrated when teenage angst is discussed - I've had to teach in secondary schools at times and 14 is the worst age - they go from thinking adults are gods straight to thinking of them as tw*ts before a year or two later they see them as mere humans, one of which they are too - good luck, hopefully Palace will provide you with some solace during your unenviable struggle, but she sounds good hearted so it shouldn't take too many years off your life.