Read the label on food packages. Specifically look for carb sugars. Every 7 grams equals one heaping tablespoon of granulated sugar. Don't be surprised when you read milk, bread & cereal labels.
Are you taking the readings after eating? Before eating? You say you are not eating any sugars, do you mean sweets. You need to start looking at the carb levels of your foods. 15 gr carb is considered one serving. I am allowed 3-4 carb servings per meal, 2 of which they prefer to be starch (not processed grains, either), one fruit...the rest from fruit or vegetables.
Your levels in the am should be before you eat anything, and at least 8 hours from eating the night before. If that is when you are doing it, they are a little high. If you are at 170 2 hours after dinner, I suggest you look at what you are eating and start considering carbs.