High-intensity interval training (HIIT) significantly impacts fat loss by burning calories and promoting metabolic efficiency. This training method incorporates short bursts of intense activity followed by brief recovery periods, elevating the heart rate and increasing calorie expenditure during and after workouts. HIIT promotes greater fat oxidation compared to steady-state exercises, making it an effective strategy for weight loss. Additionally, it can help retain lean muscle mass, which is essential for long-term metabolic health and overall fitness.