But geneticist Dr Sharon Moalem has revealed to The Times, some people are predisposed to thrive on carbs.
To find out which side of the carb fence you sit, he (yes, he) has devised a 90-second cracker test in his new book, Unlock Your Personal Genetic Code To Eat For Your Genes.
All you need to do is chew on a cracker and make a note of how long it takes for the taste to change from bland to sweet.
If it takes less than 14 seconds you are a ‘full’ carb type.
This means your body thrives on carbs and you can have up to 50 per cent of your calories from carbs, while 20 per cent should come from protein and 30 per cent from fat.
Dr Moalem says that people who are ‘full’ carb types have inherited multiple copies of the gene that makes the protein amylase, which breaks down starch.
If you have lots of copies then your body can break up molecules of starch quicker, but some people might have none at all and therefore find it hard to break down starch.
If you find it takes 15 to 30 seconds for the taste of the cracker to change you fall into the Moderate carb category and should cut down your consumption.
Take the test
To find out if you fall into the Full, Moderate of Restricted carb category all you need is an unsalted cracker and a way of timing yourself.
- Take a bite of the cracker, set your time for 30 seconds and start chewing, but don’t swallow. Paying close attention to any change in taste as it may start happening immediately, and it can be quite subtle.
- As soon as you notice a change in taste note down the time. If you reach 30 seconds without seeing a change, stop chewing.
- Repeat the test twice and note your times to get an average.
0-14 seconds – Full carb type: You’re genetically predisposed to break down carbs. You can have up to 50 per cent of your calories from carbs, while 20 per cent should come from protein and 30 per cent from fat.
15-20 seconds – Moderate carb type: Ideally you should have no more than 35 per cent of your calories from carbs while an equal amount should come from fats and 30 per cent from protein.
30 seconds or more – Restricted carb type: No more than 25 per cent of your calories should come from carbs as your body finds them hard to break down. You should opt for a higher fat diet for 40 per cent of your calorie intake, while 35 per cent should come from protein.
Ideally you should have no more than 35 per cent of your calories from carbs while an equal amount should come from fats and 30 per cent from protein.
If it takes more than 30 seconds, or you don’t notice a change in taste at all, that means your type is Restricted.
No more than 25 per cent of your calories should come from carbs as your body finds them hard to break down.
Instead, you should opt for a higher fat diet for 40 per cent of your calorie intake, while 35 per cent should come from protein.
