It's all been exactly the same for me. Put on 50 pounds in 3 months when starting quetiapine. I'm got some of it off, and now that I'm decreasing my dose and will be stopping soon the rest is gradually going. Some things really helped me:
1. Get your thyroid hormones checked. Especially if you have sleep issues. Turns out I was hypothyroid too so not all the weight was quetiapine's fault. Starting thyroxine made me loose 8 pounds.
2. Fibre supplements really help. They make you feel fulller (and help if, like me, you got constipation from the quetiapine too). I prefer soluble fibre as long as its not psyllium based, but thats because I get a lot of gas and bloating thanks to IBS. For most people any will help, I like tablets coz its easier than a powder but you have to drink a lot of water.
3. Don't stay on it any longer than you need to. If you need it then its great, but its easy for things like the tiredness to actually make you feel worse, especially if you're taking it as an adjunct for depression. I went to the psychiatrist feeling awful wanting to increase something (also on 300 venlafaxine) and when he suggested decreasing the quetiapine I was surprised, but it actually make me feel better! The anxiety I had before has gone and so far not come back, as has the rapid changes in mood, which were the two reasons I was on it.
4. If you can, avoid anything sugary (snakcs, chocolate, bread, pasta) for 3 or 4 days (lots of protein and fruit and veg). For me, it stopped the rapid changes in blood sugar levels, which is what was making me hungry - I'd snack, get a sugar boost, insulin released then causes sugar levels to crash making me want a snack... Getting out of this cycle REALLY helped me, but it probably won't help everyone. Think the venlafaxine actually helps in a way because it meant I got full from a small amount of food - when I 'grazed' constantly it meant I actually snacked more, but now that I'm eating properly it means I don't over eat at meal times.
5. Try and build exercise into your routine. Even just cycling 2 miles to work made a big difference. Easier said than done though with depression, believe me, I know!
6. For me, the quetiapine made me less depressed and therefore gave me a chance to eat right and exercise where before just showering was beyond me. If quetiapine makes you feel better in whatever way - use it if you can to beat the side effects. Kinda a mental thing rather than a practicle one, but it helped me.
Good luck to everyone. It's a pretty messy drug, but like all drugs can be very beneficial to the right people if dealt with in the right way.
Hope this helped xx