What is the single best exercise for weight loss?

Daily brisk walking. It is easy to sustain, low-impact, keeps stress hormones down, and adds up to a real calorie burn without wrecking recovery.

Do I need to do cardio to lose weight?

You need a calorie deficit. Cardio helps create it, but strength training preserves muscle so the weight you lose is fat, not tissue.

Give it 4–6 weeks of consistent movement paired with a modest food deficit. The first 2 weeks are mostly water.

hiit · kettlebell

One of the highest-calorie-burn strength moves. Fast, powerful, brutal.

5–10 × 15–20 15 minrest 45s

Included in "Fat-Burn MetCon" — 5 guided exercises with a rest timer.

Equipment

kettlebell

Rest

45s between sets

Primary muscles

glutes, hamstrings

Also works

core, shoulders, cardiovascular

Set a kettlebell one foot in front of you. Hinge at the hips and grip it with both hands.
Hike it back between your legs with a hard hip hinge.
Snap your hips forward explosively — the swing is not an arm lift.
Let the bell float to shoulder height, then let it fall back into the next hinge.