A -> B, then B -> A => incorrect
In a fire, we see firefighters, that doesn't mean firefighters cause fire. In diabetic patients, we see high glucose level. That doesn't mean eating high GI food causes someone to have diabetes.
If we look at the Blue Zone, many people eat mostly carb. So carb/high GI food definitely doesn't cause diabetes.
Devices like this will make other people fearful of high glucose and think they're getting diabetes. People without the disease shouldn't focus on monitoring the glucose level, focus on eating healthy instead. And of course eating healthy is another complex topic.