To amp up results, we combined ball exercises from the study with high-energy cardio and simple calorie-cutting tips. In 2 weeks, you could lose up to an inch from your waist; in 4 weeks, shed up to 8 pounds or more. The Experts Rafael Escamilla, PhD, PT, study author and professor of physical therapy at California State University, Sacramento, and Wayne Westcott, PhD, research director at the South Shore YMCA in Quincy, MA, designed these workouts. Program at a Glance Your Eating Plan How it works: Our Eat for a Slim Belly plan relies on simple food swaps to cut about 500 calories from your diet daily. Our recommendations also boost your intake of monounsaturated fatty acids (MUFAs) and whole grains—studies show both shrink belly fat faster. MORE: 16 Simple Ways To Eat Less Belly workoutDo 12 to 15 reps of each move in the order shown Between each exercise, do a cardio burst—2 minutes of jumping rope, marching or jogging in place, stair climbing or stepping, or doing jumping jacks. Remember to warm up and cool down by marching or stepping side to side in place for 3 to 5 minutes at the beginning and end of your workout. Cardio Burst: These 2-minute high-energy bouts will double your calorie burn to speed up fat loss and reveal a slimmer belly in less time. How to Buy a Ball Most people need a 22-inch (or 55 cm) stability ball. If you’re under 5-foot-1, choose an 18-inch (or 45 cm) one, or a 26-inch (or 65 cm) ball if 5-foot-8 or taller. They’re available in sporting goods stores (about $30) or online. We like the Gymnic Plus (performbetter.com) because it’s made with burst-resistant, latex-free vinyl, and if punctured, it will deflate slowly.

  1. Reverse Crunch(Cardio burst: 2 minutes) Lie faceup with calves resting on ball, arms at sides. Press legs into ball, squeezing it between calves and thighs. Contract abs and lift hips 3 to 6 inches off floor and pull knees toward chest. Hold for 1 second, then lower. A. Make it easier Contract abs and just lift ball off floor, keeping hips down. B. Make it harder Keeping neck in line with spine, lift head and shoulders off floor as you raise hips. Hold, then lower both upper body and hips. MORE: 10 Moves That Target Cellulite
  2. Rock And Roll(Cardio burst: 2 minutes) Start on knees, with legs about hip-width apart. Place fists on ball in front of you. Keeping body in line from head to knees and abs tight, lean forward and roll onto forearms. Hold for 1 second, then roll back to start. A. Make it easier Bend hips instead of keeping body in a straight line as you roll onto forearms, or keep body in line and roll only partway onto forearms. B. Make it harder Once you’re balancing on forearms, straighten legs and press balls of feet into floor to form a straight line from head to heels. Hold for 15 to 30 seconds and repeat.
  3. Ball Curl(Cardio burst: 2 minutes) Sit on ball, walk feet forward, and roll torso down until bottom of butt is just off ball and middle and lower back are on ball, feet together. Place hands behind head. Lean back, pressing upper back into ball, then exhale, contract abs, and curl forward until upper back lifts off ball. A. Make it easier Place feet wider than hip-width apart for more stability, and cross arms over chest. B. Make it harder Straighten one leg so it’s parallel to floor and you’re balancing on one foot. Do half the repetitions, then switch legs to finish.
  4. Skier(Cardio burst: 2 minutes) Lie over ball on all fours. Walk hands forward so ball rolls under thighs, legs together, abs tight, and body in line from head to toes. Bend knees and pull them and ball (it will roll to shins) toward right shoulder. Hold for 1 second, then roll back out and repeat to left side. A. Make it easier Hold start position—body in line from head to toes, abs contracted—for 15 to 30 seconds. Repeat one more time. B. Make it harder Start with ball under shins and let it roll to tops of feet as you draw knees in.
  5. PikeStart in the same position as the Skier, legs together, ball under thighs, balancing on hands, and body in line from head to toes. Keeping legs straight, contract abs and lift hips up toward ceiling, rolling ball to shins. Hold for 1 second, then lower. (Cardio burst: 2 minutes)

A. Make it easier Lift hips just a few inches and roll ball to about knees. B. Make it harder Start with ball under shins and roll to tops of feet and lift hips so torso is as vertical as possible, like you’re doing a handstand. MORE: Tone Your Inner Thighs With These 8 Moves Cardio Routines These calorie-melting workouts maximize fat loss, boost your energy, and improve your fitness level—fast! In one study, dieters who also walked 50 minutes 3 times a week lost nearly twice as much belly fat as women who only dieted. You can do any type of cardio exercise (walking, jogging, cycling, or using a cardio machine) with these workouts. Routine 1 (burns 225 to 675 calories*) Warm up at an easy pace for 3 minutes, then exercise at a moderate to brisk pace (breathing hard but can still talk in sentences) for 40 to 55 minutes, and cool down at an easy pace for 2 minutes. Total time: 45 to 60 minutes Routine 2 (burns 175 to 500 calories*) Warm up for 3 minutes, then pick it up to a moderate to brisk intensity for 3 minutes, then push yourself to go as fast as you can for 2 minutes (can only speak a few words at a time). Alternate brisk and fast intervals 5 to 7 more times, then cool down for 2 minutes. Total time: 35 to 45 minutes *Based on a 150-pound person doing activities such as walking (low end), cycling (mid), and jogging (high end). To read the complementary diet plan go to Eat for a Slim Belly!