Carb counting and fibre

[kegstore]

OK so I have been carb counting for donkeys years with no (!) problem. I am always looking for new ways to tweak my regime for improved control. Two huge discoveries when I went on the pump 4 years ago:

Firstly GI which I mostly have sussed now, and very very very pleased with the results I am too!

Second thing is the role of fibre in digesting carbs. It was starting with the pump I was advised to "subtract the weight of fibre from the total carb if you're eating more than 100g of carb". Hmmm, since I've never eaten 100g of carb in one sitting I ignored that, but adapted it slightly so that I now always subtract the fibre from whatever weight of carb I am eating, in order to calculate my meal bolus. Does all fibre pass through the intestines undigested, so is this the right thing to do?

 

[phoenix]

In short there are 2 types of fibre
Insoluble Fibre:
This helps bulk stools by absorbing water, and making stools heavier and preventing constipation; the classic 'roughage'.
Soluble fibre breaks down in the digestive tract to form a gel which is thought to' trap' some substances related to high cholesterol.
In far too much detail here :http://www.diabetes.co.uk/diabetes-forum/viewtopic.php?f=3&t=5497&p=43548&hilit=fibre#p43548

I don't really know why one should subtract fibre for a large amount of carbs. If you're using British carb tables/labels then the fibre has already been subtracted from the carb count so you'd be doing it twice. It would give you a lower carb count so you'd take proportionally less insulin for a very high carb meal. Perhaps this is a safety mechanism. :?:
It would make sense to always subtract it when using tables from the US. There they give the total carb count including fibre and then the fibre separately so one needs to subtract the fibre to give the net carbs.(they also use a different method for analysing so will often show higher amounts of fibre)

 

[kegstore]

Thanks for the info phoenix, not sure I'm any further on though! I was surprised to read about UK and US labels. On most UK food labels, fibre is listed separately from carb, and these are the figures I tend to work with. The difference in bolus can be substantial (if you're on a relatively low TDD anyway).

Example: a tub of supermarket-prepared salad, carb listed as 12.6g per 100g, fibre listed as 6g per 100g. So 200g of this (ie lunch) could contain either 13.2g or 25.2g of carb requiring insulin. First figure I'd bolus 1 unit, second figure I'd bolus 2 units. For my insulin/carb ratio this difference could be enough to send me hypo, using my bg target of 6 mmol/l, and depending on the starting bg.

I know the usual method of determining this would be to test, test and test again, trouble is I quite often appear to get different reactions to the same (type of) food, so what works one day doesn't necessarily the next.

I'd be really interested to hear what rules others use.

 

[phoenix]

Example: a tub of supermarket-prepared salad, carb listed as 12.6g per 100g, fibre listed as 6g per 100g. So 200g of this (ie lunch) could contain either 13.2g or 25.2g of carb requiring insulin. First figure I'd bolus 1 unit, second figure I'd bolus 2 units. For my insulin/carb ratio this difference could be enough to send me hypo, using my bg target of 6 mmol/l, and depending on the starting bg.

Its difficult to make clear.

In UK (actually it's EU legislation).
If label says 12.6 g carbs per 100g and 6g fibre per 100gm.
Thats 12.6g actual carbs+ 6 g fibre .
We shouldn't need to bother with the fibre at all (except to note that a lot of fibre will probably result in lower gi)

A similar product in the US would be labelled 18.6 g carbs, 6 g fibre so they can subtract it to get the 12.6 g 'net' carbs.
The Americans are normally advised to subtract amounts of fibre over 5g per 100g

(The difference caused also some misunderstanding in the US. A certain brand of crispbread , made in Norway was labelled 6 g carb and 6 g fibre, it was proclaimed by some people to be a miracle no carb product until the labelling difference were pointed out :lol: )

If you have been subtracting an amount for fibre then it would obviously make a difference to your ratio if you changed things. Other than that it's the time honoured method of trial and error.