Can rapid weight loss or fasting trigger gout?

Yes, and the possibility is not small. This has to do with how our bodies process energy and waste.

You can understand it this way:

The Body's "Panic Mode": When you suddenly starve yourself (fasting) or lose weight too quickly, your body thinks you've encountered a famine and enters a "panic mode." To survive, it starts breaking down its own fat and protein for energy. This process produces a byproduct called "ketone bodies."
Kidney "Traffic Jam": Our kidneys are like "waste treatment plants," responsible for filtering waste products from the blood (such as "uric acid," which causes gout, and the "ketone bodies" mentioned above). Normally, everything exits in an orderly fashion. But when you lose weight rapidly, a large amount of ketone bodies suddenly appear in your blood. They also need to be excreted by the kidneys, and they often take priority. This is like a sudden rush of cars at an exit, blocking the uric acid that was originally trying to get out. Uric acid can't be excreted, and its concentration in the blood skyrockets.
Cellular "Remains" Release Uric Acid: Rapid weight loss means a large number of fat cells and some muscle cells "die" and decompose in a short period. Cells themselves contain purines (the raw material for uric acid). When they decompose, they release a large amount of purines, which the body then metabolizes into uric acid. This is like adding a large batch of new uric acid to an already "congested" bloodstream.

In summary:

Rapid weight loss/fasting = (Kidney uric acid excretion channels are crowded out by ketone bodies) + (Large number of cells decompose and release new uric acid) = Drastic increase in blood uric acid concentration -> Induces acute gout attacks.

Therefore, for people with a history of gout or high uric acid, losing weight is a good thing, as it can fundamentally improve metabolism, but you absolutely cannot rush it. You need to lose weight steadily and slowly, like "boiling a frog in warm water."

Here are some suggestions:

Take it slow: Losing 2-4 kg (4-8 pounds) per month is a relatively safe pace.
Drink plenty of water: Drinking enough water can help the kidneys excrete uric acid more effectively. This is the simplest and most important point.
Balanced diet: Even when losing weight, ensure a balanced diet instead of eating nothing.
Consult a doctor: If your uric acid is already high and you want to start a weight loss plan, it's best to consult a doctor first. Sometimes doctors may suggest taking uric acid-lowering medication in the initial stages of weight loss to prevent gout attacks caused by rapid weight loss.