Cardio for fat loss: how much, what kind and when

Cardio is useful, but not for the reason most people think. It does not melt fat by itself — it raises daily expenditure, and the deficit removes fat.

What cardio actually burns

For an 80 kg person:

• Brisk walking 30 min — about 150–200 kcal
• Easy jogging 30 min — 300–350 kcal
• Moderate cycling 30 min — 250–300 kcal
• HIIT 15 min — 150–200 kcal (plus a small afterburn)

For comparison, one pastry is 500–700 kcal. That is why cardio alone rarely solves the problem — food decides.

Steady state (LISS) or intervals (HIIT)

• LISS (walking, cycling, cross-trainer for 30–45 min): easy to recover from, does not interfere with lifting, easy to do daily.
• HIIT (for example 8 × 30 s hard / 90 s easy): saves time, but creates fatigue that overlaps with weights. One or two sessions a week at most.

For someone who lifts, LISS is usually the better choice because it does not steal recovery from strength training.

The most underrated tool: steps

The difference between 4,000 and 10,000 steps a day is 200–350 kcal — every day, with no fatigue and no dedicated session. Over a month that is 6,000–10,000 kcal, close to a kilogram of fat. No cardio workout beats that over the long run.

When to do cardio

• After weights or in a separate slot — never before a heavy strength session.
• If it must be the same day, leave at least 6 hours before a heavy lower body session.
• Fasted morning cardio has no special advantage; do it when it suits you.

How much per week

• For health: 150 minutes of moderate cardio a week (WHO guideline).
• For fat loss alongside weights: 2–4 sessions of 20–40 min, plus 8,000+ steps a day.
• If your strength starts dropping, cut cardio before you cut food.

Mistakes

• Replacing weights with cardio while dieting → you lose muscle and end up softer at the same weight.
• Rewarding yourself with food ("I burned 400 kcal") — that gets eaten in two bites.
• Trusting the machine — treadmill calorie counters overestimate by 20–30 %.

The short version

• Cardio supports the deficit, it does not replace it.
• LISS 2–4× a week alongside weights; HIIT once or twice at most.
• Daily steps are the biggest quiet calorie cost.
• If strength falls, reduce cardio.