One caveat before the routine: no abs workout reduces belly fat directly. Fat loss happens through a calorie deficit that affects the whole body. What abs workouts do is build the muscles that emerge once the fat is off. This routine does that work efficiently.

The 15-minute routine (3 rounds)

Round structure — 40 seconds work, 20 seconds rest

1. Dead bug — lie on back, opposite arm/leg extensions. Teaches anti-rotation; protects lower back.
2. Plank — forearms, straight line from head to heels. Isometric strength for the whole core.
3. Bicycle crunches — classic; controlled, not rushed.
4. Leg raises — lie flat, lift straight legs to 90°, lower slowly.
5. Russian twists — seated, lean back, twist side-to-side. Optional weight for progression.
6. Hollow body hold — lie on back, lift shoulders and legs slightly. Core under tension.

Progression

Weeks 1-2: 3 rounds. Weeks 3-4: 4 rounds. Month 2: add resistance (dumbbell on chest for crunches; ankle weights for leg raises).

Nutrition for visible abs

Body-fat percentage below ~15% for men and ~22% for women is roughly where abs become visible. Routine + calorie deficit (300-500 kcal/day) + adequate protein (1.6 g/kg) produces visible results in 8-12 weeks for most people starting from average body composition.

15 minutes, three times a week. Lower fat alongside through diet. That's the honest version.