Gout is caused by too much uric acid in the blood leading to crystals of uric acid in the joints which can then trigger very painful attacks of hot, swollen joints. If you have gout, the uric acid levels in your blood can be reduced by weight loss, avoiding purines from animal sources and yeast extract, and by keeping alcohol intake to 1-2 units per day or less. 

You can also help reduce the number of gout attacks you have by drinking plenty of fluids, especially water, but you should avoid drinks sweetened by sugar or too much fruit juice as these can trigger an attack. Diet drinks are fine. Increasing your intake of cherries either as fruit or juice, and drinking skimmed milk may also help prevent gout attacks.