141 mg/dl would be about 7.9 mmol/l which is still within the normal range, so not too high. Blood sugar readings involve more than food eaten and insulin taken. If you ate the same food at the same time and took the same insulin then one of the other factors involved was the reason for the different reading. Weather, emotion, stress, possible oncoming illness are only some of the other factors involved and there are likely more that we are not aware of.