A rapid rise in blood glucose, followed by a rapid fall, can often make you feel hungry again quite soon after a meal. It's as true for pasta, potatoes, white rice and white bread as it is for sugary sweets and cakes. Dieticians emphasise the importance of eating foods that are rich in fibre, as these foods produce a much more gradual rise and fall in your blood sugars.
Cooking pasta and then cooling it down changes the structure of the pasta into "resistant starch" as it then becomes resistant to the normal enzymes in our gut that break carbohydrates down and release glucose that then causes the familiar blood sugar surge. If you cook and cool pasta down then your body will treat it much more like fibre, creating a smaller glucose peak and helping feed the good bacteria that reside down in your gut. You will also absorb fewer calories, making this a win-win situation.
But many people don't really like cold pasta. So an experiment looked as what would happen if you took the cold pasta and warmed it up. Volunteers were randomised to eating either hot, cold or reheated pasta on different days. On each of the days they also had to give blood samples every 15 minutes for two hours, to see what happened to their blood glucose as the pasta was slowly digested.
Just as expected, eating cold pasta led to a smaller spike in blood glucose and insulin than eating freshly boiled pasta had. However, cooking, cooling and then reheating the pasta had an
even more dramatic effect.
In fact, it reduced the rise in blood glucose by 50%. This suggests that reheating the pasta made it into
an even more "resistant starch". It's an extraordinary result and one
never measured before.Trust Me, I'm a Doctor, series two, BBC2.
