While not usually nine days old, some foods
taste better the second time than when first cooked. Many people say
leftover pasta tastes great. Now an experiment has shown that it
also might be better for us.
Pasta is a form of carbohydrate and like all carbohydrates it gets
broken down in our gut and then absorbed as simple sugars, which in
turn makes your blood glucose quickly rise. In response to a surge
in blood glucose our bodies produce a rush of insulin to get our
blood glucose back down to normal as swiftly as possible, because
persistently high levels of glucose in the blood are extremely
unhealthy.
A rapid rise in blood glucose, followed by a rapid fall, can often
make a person feel hungry again quite soon after a meal. It is true
of sugary sweets and cakes and also true for things like pasta,
potatoes, white rice, and white bread. That is why dieticians
emphasize the importance of eating foods that are rich in fiber, as
these foods produce a much more gradual rise and fall in blood
sugars.
Cooking pasta and then cooling it down changes the structure of the
pasta, turning it into something that is called 'resistant starch'.
It is called that because once pasta, potatoes or other starchy food
is cooked and cooled it becomes resistant to the normal enzymes that
break carbohydrates down and release glucose that causes a blood
sugar surge.
According to Dr. Denise Robertson, from the University of Surrey, if
you cook and cool pasta down then your body will treat it much more
like fiber, creating a smaller glucose peak. You will also absorb
fewer calories.
A study was conducted and volunteers had three days of testing,
spread out over several weeks. On each occasion they had to eat
pasta on an empty stomach. The volunteers were randomized to eating
either hot, cold, or reheated pasta on different days.
On one day they ate the pasta, freshly cooked and hot with a plain
sauce of tomatoes and garlic. On another day they had to eat it cold
with the same sauce, but after it had been chilled overnight. On a
third day they ate the pasta with sauce after it had been chilled
and then reheated.
On each of the days they also gave blood samples every 15 minutes
for two hours, to see what happened to their blood glucose as the
pasta was slowly digested. Eating cold pasta led to a smaller spike
in blood glucose and insulin than eating freshly boiled pasta.
Cooking, cooling, and then reheating the pasta had an even smaller
effect on blood glucose. It reduced the rise in blood glucose by
50%.
We can convert a carb-loaded meal into a more healthy fiber-loaded
one without changing a single ingredient, just the temperature.
Leftovers could be healthier than the original meal.