Counting carbs & reading labels

Jun 26, 2023

In this article we forget all about counting calories and focus on carbohydrates. We therefore focus on the exact foods that impact the blood sugars. I get asked about this frequently because once you start delving in to detail; it can get confusing!

The first step is to know how many carbohydrates to eat in a day. The best place to start is by knowing how much you currently consume. The average UK citizen is thought to consume around 300g/day!


The image above shows guideline ranges. The numbers refer to net carbs; you will find different ranges online depending on where you look but this is what we use in our clinic.

In essence; the least carbohydrates you eat the more restrictive you have to be. Eating less than 20g of carbs a day (as with the ketogenic diet) will give you energy, it will keep you full & you will have rapid weight loss. However, you will need to be obsessed with knowing the numbers of carbs & be strict with restricting foods. Deciding how low you want to go needs to be sustainable for the long-term and in line with your personality traits.

When deciding on your targets it’s important to remember that the number does not have to be set in stone. It is OK to ‘carb cycle’ and chose varying amounts in line with your monthly cycle, the seasons or any other life events you might encounter!


Reading Labels

Internet searches can leave you confused as you will find two ways of counting carbs; the ‘net carbs’ and the ‘total carbs.’


Net Carbs

In the UK – the number that is put on food labels is the Net carbs – so the calculation is easy.


So you can see here – if you were aiming for less than 50g of carbs a day – then you can see that one fish fillet contains 25.1g of carbs therefore that one fillet has taken 50% of your allowance for the day!


Total Carbs

However you will also discover ‘Total Carbs’ on recipes and advice that comes from America.

So what is the difference? The difference lies in whether that number includes fibre or not.

Fibre is a type of carbohydrate that the body cannot fully digest or absorb. We need the help of our gut bacteria to break these down. We know these live in our large intestine and the journey there takes many hours meaning that the higher the amount of fibre, the slower the glucose release. And there are bigger health benefits to fibre than just blood sugar, the more fibre we eat the less likely we are to have cancer & to be overweight. High fibre consumption is linked to good mental health and the least amount of food cravings.


The total carbs includes the fibre.  

The net carbs is the total carbs without the fibre.


So why does it matter?

Because it is only the net carbs that affect the blood sugar. We know that the fibre in complex carbs (eg vegetables) are good for us and I would encourage you to eat more of these. It is the net carbs which is the number we want to be low.


Calculating Total Carbs on UK food labels

There are certain scenarios when it is helpful to know the amount of fibre. The fibre in ‘real’ food; vegetables for example causes no meaningful impact on the blood sugar.

However ultra-processed food (eg ready-meals) can contain a variety of fibre that does increase the blood sugar. In this scenario, you would be better off knowing the amount of fibre in the food (the total carbs.) The British way of deducting the carbs would mean it would underestimate the impact on you blood sugars without you realising it.


To calculate the total carbs (from a UK food label) you would have to add the fibre:

Total Carbs = Net carbs + fibre 

Of which sugars

This refers to the amount of sugar; those that occur naturally and added. They are grouped together and are used for the traffic light system that we see on the front of food packaging.  This number is calculated within the Net Carb amount.

4g ‘of which sugars’ is equivalent to roughly 1 tsp of table sugar.

Portion Sizes

Be aware of portion sizes: Pay attention to the serving size indicated on food labels and adjust your carbohydrate counting accordingly. If your portion differs from the serving size mentioned, you'll need to calculate the carbohydrates based on the actual amount you consume.


Of course, it is always best to avoid ultra-processed foods. Many snacks/meals that are advertised as ‘keto’ or ‘low carb’ may well indeed be low in carbs but it is always worth remembering that they may also contain additives and chemicals that would cause inflammation and not be in line with our health goals. A general rule of thumb to know that something is processed – is to look at the ingredient list and if there are names you don’t understand – or even if there are more than 5 ingredients – then please avoid it. 

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