Most Spiders prey on flies, but there is one fly which preys on spiders. Known as the spider-eating fly, it can grow up to an inch in size. Its natural predator is the spider-eating-fly-eating-spider, which is, frankly, enormous.
The "fact" that on average, people eat at least one spider per year is misleading, whilst true on some level. Every year in Warwickshire, there is held a spider-eating contest, and the competitors, whilst few, eat such a quantity of spiders in worldwide spider eating events, and in practice sessions, that on balance, they eat at least one for every man woman and child in the UK within the space of a year.
Please do not emulate professional spider-eaters. If you see a spider, consult with an expert before consuming it, as many are poisonous and could make you ill.
All content copyright Tom Crowley