I would say if depends on your definition of "bad". In general, the NHS definition of bad is anything full fat, so butter, meat with fat on - but these do not raise blood glucose levels. The NHS definition of "good" (in general again) is the Eatwell Plate, and advice to eat brown bread, rice, pasta, low fat everything..but no mention of the sugar that these things contain. These foods are still carbohydrate, and they will still raise blood sugar levels. How much they raise them is why people are advised to use a meter.
Test strips for meters are very expensive. There is also no perceived risk of hypo for a type 2 on metformin or diet, so it is not deemed necessary for those with type 2 to have one, instead relying on the HbA1c, which can happen every 3 months, or 6, or 9 and in some cases 12. If somebody is eating foods that they have been advised is good for their diabetes, and it is in fact raising their levels significantly, they won't know about it. So the HbA1c gets higher and higher, more meds are brought into the mix, and the person concerned is left wondering what the hell has gone wrong..is it any wonder we are told it's a progressive condition?
My next appointment with the diabetes nurse isn't until October so maybe I should try and find my meter. If i can't find it, does anyone know of one that is reasonable for meter plus test strips?