arthritis sufferers & water retention

Sorry if this repeats previous posts but have other arthritis sufferers noticed big weight gains when their arthritis is inflamed?
Last week mine was very bad & I weighed 7lbs more than I do today, didn't matter what I ate it would not change, my physiotherapist agreed that it is normal. Joints retain the fluid to aid mobility hence increased weight, just thought it may be worth sharing as it is quite dispiriting when you feel poorly & could easily discourage any of us to stick with the healthy plan.