It's important to understand the data represented in the glucose graph, which can be accessed on the Home Tab as a Timeline item, or from the top of the Home tab by scrolling left and tapping Nutrition. 

• Daily Glucose Average: The average of your blood sugar readings over a 24-hour period. This helps you understand your overall glucose level day by day.
• Time In Range (TIR): The percentage of time your glucose stays within a healthy range, which is defined on the graph by the dotted line. A higher TIR means better control of your blood sugar.
• Glucose Level Variability: How much your glucose levels fluctuate throughout the day. Lower variability is a sign of better metabolic stability. Learn more about glucose ranges and fluctuations (known as 'spikes') here.

Important: Both the default healthy glucose range and TIR are altered by enabling Diabetic Mode, intended for users with diabetes.