Your daughter's after meal glucose reading is elevated, and her waking sugar is higher than the "normal" range of between 70-126 also. The hunger, thinness and fatigue DO sound suspicious of type 1 diabetes, for these are all frequently present in type 1 kids and teens. Another symptom that she would be showing if diabetic would be excessive thirst, and you have not mentioned this as a symptom she displays.
I think you would be smart to have her tested for diabetes. The readings from the home monitor could be just a fluke after meals with heavy carbohydrate content, but a glucose tolerance test or even a fasting glucose test from a lab may be helpful. Since she is showing signs of fatigue as well as the hunger, the source of these symptoms should be discovered and treated even if diabetes is not the problem. I would advise you to call her doctor, tell him of her symptoms and the glucose readings and make an appointment for a more thorough check-up.
Even if the only abnormality is hypoglycemia, some diet changes could make her life more pleasant if this is indeed her problem, and a doctor could give you information about how to manage this problem.
If she is indeed diabetic, or perhaps still making some insulin, but not enough, the remaining insulin-producing cells may be preserved for a while by starting her on treatment for diabetes. Several studies have shown that small doses of insulin for kids who are still in the so-called "honeymoon" phase (whereby their pancreases are stil producing some insulin) can help preserve their ability to make insulin on their own and ease the control of their glucose levels. I was diagnosed at age 12 after an unrelated virus made me sick enough to require some bloodwork, and before blatant symptoms of diabetes had appeared. I still require a very low dose of insulin and find that my diabetes is easily controlled, and these studies would seem to indicate that I was perhaps one of these honeymoon phase kids even though I started the insulin 35 years ago.
So to make a long response short and succinct, yes, I would encourage you to follow up with her doctor for some routine tests to try to discover if there is indeed a problem. If there is no health problem, then you have reassurance, but if there IS a health problem, you can catch it early enough to help her before damages happen or before her pancreas gives out entirely. Even if she is just beginning to have troubles with her insulin production, these tests and your note of her symptoms can go in her medical records as a basis for her pancreas health for later comparison as she matures.
As you probably know from reading this forum, we're not physicians. Having clarified that, tho', I would encourage you to talk to your daughter's doc very soon. It is not uncommon that Type 1 diabetes is preceeded by a period of hypoglycemia, tho' it's not always the case.
Type 1 is an auto-immune disease, and at least at this point in the research, it appears unrelated to Type 2 -- much more common among overweight adults. There is soem Type 2 appearing in overweight kids, but your daughter is UNDERweight.
A child who is underweight with the symptoms you describe may well be diabetic. Despite eating and drinking a lot, when we lack sufficient insulin to get that energy (sugars from metabolized foods) into our cells, the sugar stays in our bloodstream and the cells, literally, starve. The weight loss comes because the calories taken on are mostly removed in our urine.
It's great that you've been keeping records and are so aware of your daughter's behaviors and moods. Best to share all this info with your pediatrician and get a referral to a pediatric endocrinologist, who are specialists in caring for munchkins with diabetes. All diabetics need to be caref for by a specialists. Our GPs are ill-equipped and less informed on the details, latest treatment options, and complications-prevention technique. Good luck. This may be a difficult journey, but please know you are not alone in it.
Please do check in to let us know what you find out.
Dencarr is right. If something is causing juvenile diabetes, it may be possible to slow down its progression by giving her insulin shots. On the other hand, it could be something unrelated to diabetes. Get her to the doctor. Give the doctor all her fasting blood glucose readings. You should be recording one every morning. Take the glucometer to the doctor when you see him so that you can check the glucometer's accuracy at the doctor's office.
Good luck and let us know how it works out,
Nick