High Intensity Interval Training (HIIT) is the most effective fat shredding form of cardio. It boosts your metabolism, meaning you burn more fat even after you have finished training.
HIIT cardio consists of short burst of energy, followed by short periods of rest. It is typically performed on treadmills, exercise bikes or any other stationary equipment at the gym.
It can be implemented outside, by sprinting, skipping, or biking in intervals.
Give 90-100% maximum output during the working period, and 30-50% during the rest period.