Gastric bypass surgery

According to the NHS, your Body Mass Index (BMI) should sit somewhere between 18.5 and 24.9. Anything over that, and you're overweight.

So something's gone seriously wrong when you're just 14 years old and your BMI is a whopping 100.

The world's heaviest man, who at one point weighed almost 600 kilograms, has undergone successful gastric bypass surgery, his doctors in Mexico said.