Post-meal spikes in glucose can be uniquely damaging to health and minimizing them should be a dietary priority. Keeping glucose levels steady over time leads to better health outcomes.
There is simply no one-size-fits-all metabolic eating plan that works for everyone. Different people can have very different glycemic reactions to the exact same foods, and the metabolic impact of lifestyle choices and other individual factors are difficult to measure with traditional tools.
Having a fasting glucose level in the "normal" range may not be good enough: research shows that a higher fasting glucose level (even in the "normal" range) increases risk of chronic disease. Dietary choices have a strong impact on fasting glucose levels.
Viewing diet through the lens of glucose levels can be a powerful way to personalize food choices and optimize metabolic health.