Sugar intake directly impacts energy levels throughout the day by influencing blood sugar fluctuations. High sugar consumption can lead to quick spikes in blood glucose, providing a temporary energy boost followed by a sharp decline, often referred to as a "sugar crash." These fluctuations can cause feelings of fatigue and irritability. Consuming complex carbohydrates and fiber-rich foods instead provides a more stable, prolonged energy release. Balancing sugar intake with adequate nutrient intake supports sustained energy levels and contributes to better overall metabolic health.