Help!!!! Doc has told me to eat 1000 cals a day with no help.

[MyBloominMarvellousYoni]

My psychiatrist has told me to go on a diet of 1000 cals a day as the meds I am on cause huge weight gain and can cause diabetes. (quetiapine)

Where on earth do I start? Is there anyone doing similar? What do you eat?

Also, is there anything my gp can prescribe to try and counteract the weight gain?

I am already overweight which is why the psych has said this.

My calories occassionally come in at around 900 - 1100 per day. Normally those days would be:

Breakfast
Slimfast shake with skimmed milk and a banana
or
Protien shake (whey protein powder, 5 strawberries, half a banana, 200 mls skimmed milk, blended)
or
Small bowl of nut and seed museli with a handfull of blueberries, 5 chopped strawberries and two large tablespoons of reduced fat greek yoghurt

Lunch
3 egg omelet with mushrooms and finely chopped spinach
or
Crab Salad (made with 1 tin of white crab meat, a large handfull of shredded iceberg lettuce, an inch of sliced cucumber, 1 cooked beetroot, a quater of a red onion, 4 cherry tomatos - halved, half a yellow pepper - slliced and some reduced fat salad dressing)
or
This with a poached egg on top and toasted pumpkin seeds

Dinner
Fish or chicken with roasted or steamed veg, but no white potatos
or
Baked sweet potato with half a tub of reduced fat cottage cheese mixed with spinach and a mixed leaf side salad.

I also do not live off of 1000 regularly it's just when I track my calories, they do occasionally come in that low, normally on days I am working split shifts and have very little time to prepare meals.