Why HIIT burns more fat in less time
HIIT alternates short bursts of maximum effort with active recovery. What makes it superior is not just what you burn during the workout, but what happens AFTER. The EPOC effect keeps your metabolism elevated for up to 48 hours. A 2023 study in the British Journal of Sports Medicine showed that 20 minutes of HIIT 3 times per week burned 28.5% more fat than 40 minutes of moderate cardio 5 times per week. Less time, more results.
The 20-minute HIIT routine (no equipment)
This routine uses only your bodyweight. 4 blocks of 4 minutes with 1 minute rest between blocks. Within each block: 30 seconds work, 10 seconds rest, x6 rounds.
- Block 1: Burpees (the king of HIIT — works entire body)
- Block 2: Mountain climbers (core + cardio + coordination)
- Block 3: Jump squats (legs + glutes + power)
- Block 4: High knees (pure cardio + maximum calorie burn)
How many calories you actually burn
In 20 minutes of intense HIIT, a 70kg person burns 250-400 calories during the session. But EPOC adds another 100-200 calories over the next 24-48 hours. Total: 350-600 effective calories per 20-minute session. With Renzy you can log your workout with a quick tap and see exactly how burned calories adjust your daily caloric budget.
Renzy calculates all of this for you
Scan your food with a photo. Calories, macros and micronutrients in 3 seconds.
Mistakes that ruin your HIIT
Most people do HIIT wrong. These mistakes drastically reduce effectiveness and increase injury risk.
- Not going all-out during work intervals (should be 85-95% capacity)
- Doing HIIT every day (3 times per week is the sweet spot)
- Skipping warm-up (5 min of joint mobility prevents injuries)
- Rest periods too long (30 sec max between exercises within a block)
- Ignoring form for speed (a bad squat is a broken knee)
- Not eating protein within 2 hours post-workout
Your weekly HIIT + nutrition plan
Combine 3 HIIT sessions with 2 strength days and 2 active rest days. Post-HIIT nutrition is key: you need 20-30g protein within 2 hours. Use Renzy to plan meals around your workouts.
- Monday: HIIT 20 min
- Tuesday: Upper body strength
- Wednesday: Active rest (30 min walk)
- Thursday: HIIT 20 min
- Friday: Lower body strength
- Saturday: HIIT 20 min
- Sunday: Full rest
Renzy calculates all of this for you
Scan your food with a photo. Calories, macros and micronutrients in 3 seconds.
