While both cardio and weight training can help with weight loss, cardio is generally better for burning calories and losing weight in the short term. Cardiovascular exercise raises the heart rate and keeps it elevated, strengthening the heart and lungs while boosting metabolism to burn more calories. Over time, adding muscle through weight training can increase calorie burning as muscle uses more energy than fat at rest, but cardio is more effective for direct fat burning during a workout. Both should be included in a well-rounded fitness routine for optimal health and weight loss.