Carbs are getting a lot of airtime, and new research seems to be constantly turning what we have believed about them for years on its head.

Recently, studies have found that it might be better to eat carbs at night than in the morning, and that eating pasta regularly in a diet could actually aid weight loss.

It's a confusing time to be a pasta or pizza lover.

So how many carbs should you be eating?

According to geneticist Sharon Moalem, "the cracker test" can help you to discover how well your body digests carbs and therefore give an indication of your carb tolerance.

He outlined it in his 2016 book The DNA Restart: Unlock Your Personal Genetic Code to Eat for Your Genes, Lose Weight, and Reverse Aging.

In a new BBC documentary titled The Truth About: Carbs, Dr. Xand van Tulleken, a self-professed carb lover, put the test into practice with a group of students.

"The truth is that some of you can eat as many carbs as you like, while others have to watch it," van Tulleken said, adding that he considers himself to be in the latter category - he once weighed 19 stone (266 pounds).

Each student was instructed to chew an unsalted cracker for 30 seconds and raise their hand when the flavour began to change - if, say, it started to taste sweeter.

The student who noticed a change in the shortest time raised their hand after 17 seconds, while another did not do so until after 35 seconds. Some said they did not notice any change in flavour.

"Seventeen seconds is quite fast," van Tulleken said, adding that, according to Moalem's research, "this suggests you have a high concentration of amylase enzymes in your mouth which are chopping up the big starch molecules into smaller molecules of sugar or sugar-like molecules that you can taste."

He added: "That means that you should be able to eat a lot of carbs without having any problems."

But for the students who noticed a change later, van Tulleken explained that it might mean they should watch their carb intake more so than those who observed a change earlier.

Finally, for those who didn't notice a change, the theory suggests it's because they have a low concentration of these enzymes in their mouths and "might struggle eating carbs," van Tulleken said.

He said that, generally speaking, if you try the test at home and don't notice a change after 30 seconds, it could mean that, like him, you have a lower tolerance for carbs and might want to ease off the white and beige variety.

He added that while it's still early days with Moalem's research, "the cracker test demonstrates just how varied our carb tolerance is".

This article was originally published by Business Insider.

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