This might sound crazy, but letting your pasta cool down and then reheating can actually make it significantly less fattening.

The findings were uncovered by Michael Mosley on the latest episode of BBC 2’s health program Trust Me, I’m A Doctor.

The reason that high-carb foods like pasta are so fattening in the first place is because carbohydrates are broken down and absorbed as simple sugars.

So when you eat them, your glucose levels spike, prompting your body to produce insulin to balance those blood sugar levels back out. This usually happens pretty quickly, and then you find yourself hungry again.

This is why health experts suggest eating foods that are also high in fiber – fiber resists digestion and breaks down slower, leading to a more stable and gradual release of glucose into the blood.

But what does all this have to do with pasta? Well, it turns out that letting pasta cool down actually alters its structure, turning it into a “resistant starch” that acts more like a dietary fiber (as opposed to a carb) during digestion.

But nobody wants to eat cold pasta, right? So Trust Me, I’m a Doctor teamed up with University College London to carry out an experiment.

They gathered a number of volunteers and had them eat freshly cooked, cold, and reheated pasta (with tomatoes and garlic) for three full days, spread out over a few weeks.

They always ate on an empty stomach, and gave blood samples every 15 minutes for 2 hours as they digested their meals. Mosley reported the findings:

“Just as expected, eating cold pasta led to a smaller spike in blood glucose and insulin than eating freshly boiled pasta had. But then we found something that we really didn’t expect – cooking, cooling and then reheating the pasta had an even more dramatic effect.

“Or, to be precise, an even smaller effect on blood glucose. In fact, it reduced the rise in blood glucose by 50 percent. This certainly suggests that reheating the pasta made it into an even more ‘resistant starch’. It’s an extraordinary result and one never measured before.”

Read more from Science Alert and the BBC.