probably the pot with water weighs more than 100g?
Beware of "instant" porridge, they tend to have added sugar and the oats are more processed. Better to go for "proper" porridge, I use mornflake oats, they take 3 1/2 mins in microwave, so not much longer.
It doesn't actually go up.
The website says that 100g as consumed with added water has 15.7g carb
The contents of the pot, with added water weighs 225g (2.25 x 15.7 = 35.3)
As others say, the product is made from oat flakes (probably very fine) has added sugar and is likely to be far higher GI than porridge made from rolled oats with no sugar. http://groceries.morrisons.com/webs...tainer=|102705|150152|150178|150180_SHELFVIEW