In addition to the total carbs, it is also useful to consider how quickly those carbs are absorbed. This is known as glycaemic index (GI). Whilst there are websites (e.g.
http://www.glycemicindex.com/) which tell you the value for various foods (with 100 being equivalent to pure sugar and digested very quickly), this is only an indication as different people digest different food at different rates. This is why many contributors on this forum advocate getting a BG meter and checking 2 hours after eating to see how different foods affect you.
There are some useful things that have come out of the GI research which help with choosing foods.
- fat reduces the GI which is why chocolate is not a good treatment for a hypo.
- fibre reduces GI a little which is why wholefood is generally better than white rice/pasta/bread. And, I suspect ready made mash has little fibre so is broken down and absorbed very fast.
- There is also a complex scientific reason why rice has a very high GI (Jasmine rice has a higher GI than pure sugar). This explains that weird feeling of hunger many people (including me) feel after eating a meal with lots of rice: we are full when we finish eating but not for long.
Unfortunately, it is all rather confusing at first but once you get to understand your body, things get easier.