Marie Claire shows you how to shrink your body in four weeks! Follow this easy one-week regimen four times in a row. It's designed especially for those who like to keep their weekends exercise-free. "You can look noticeably slimmer and stronger in as little as one month," says David Kirsch, owner of NYC's Madison Square Club gym.

MONDAY
Target your butt, legs, and abs.

What to do:

20 minutes of cardio activity
If you work out in a gym, try running on an elliptical trainer or riding an exercise bike with little or no resistance. If you work out at home, try walking briskly, jogging, or shadow boxing.

20 squats
To do: Stand with your hands by your sides. Sit back while raising your arms in front of you for balance until thighs are parallel to the floor. Resume your starting position.

20 lunges
To do: Stand with your hands on your hips. Step forward with your right leg until your right thigh is parallel to the floor. Resume your starting position, then step forward with your left leg.

25 dead lifts
To do: Stand with your arms hanging in front of your body with a three- to five-pound weight in each hand. Bend forward from your waist until your knuckles touch the floor. Resume your starting position.

40 crunches

40 reverse curls
To do: Lie on your back with your arms by your sides. Raise your legs toward the ceiling until they are perpendicular to it. Raise and then lower your butt two to four inches off the floor.TUESDAY
Target your arms and chest

What to do:
20 minutes of cardio activity
15 to 20 regular or bent-knee push-ups, whichever you feel you can handle.

20 chest presses
To do: Lie on the floor with a three- to five-pound weight in each hand, arms bent, hands by your shoulders, palms facing each other. Push and rotate the weights toward the ceiling until your arms are straight and your palms are facing your toes. Slowly resume your starting position.

20 chair dips
To do: Sit on the edge of a chair with your knees bent, feet flexed, toes up with your weight on your heels. Grab the front of the seat, wrapping your fingers underneath. Keeping your back straight, use your arms to lower your torso in front of the chair until your elbows are shoulder-level. Resume the previous position.

40 biceps curls (20 per arm) holding a five- to eight-pound weight

WEDNESDAY
Target your back and shoulders

What to do:
20 minutes of cardio activity

25 jumping jacks holding one- to three-pound weights in each hand

20 lateral raises
To do: Stand with your feet shoulder-width apart, holding a three- to five-pound weight in each hand. Turn your palms toward each other, then raise your arms straight out to each side until they are shoulder-height. Slowly lower them.

40 front raises (20 per arm)
To do: Stand with your hands by your sides, holding a five-pound weight in each hand. Raise your right hand in front of you until it's shoulder-height. Slowly lower it, then raise and lower your left hand.

20 shoulder presses
To do: Stand with your hands by your sides, holding a three- to five-pound weight in each hand. Bend your arms and position your hands in front of your shoulders, palms facing forward. Raise your arms above your head until they are straight, then slowly lower them.THURSDAY
Target your butt, legs, and abs

What to do:
20 minutes of cardio activity

30 donkeys (15 per leg)
To do: Get on all fours. Keeping your back straight, bring your right knee into your chest, then kick it straight out and up. Resume your starting position, then switch legs.

15 squats
To do: Sit on the edge of a chair with your knees bent, feet flexed, toes up, with your weight on your heels. Grab the front of the seat, wrapping your fingers underneath. Keeping your back straight, use your arms to lower your torso in front of the chair until your elbows are shoulder level. Resume the previous position.

20 pelvic lifts
To do: Lie on your back with your knees bent, feet flat on the floor, arms by your sides. Raise your butt toward the ceiling (about three to five inches off the floor), then slowly lower it.

40 oblique twists (20 per side)
To do: Lie on your back with your knees bent, hands behind your head. Using your stomach muscles, lift your head and shoulders off the floor as you rotate your torso to the right. Switch sides.

FRIDAY
Target your trouble spot
"Think of this as work-on-your-weakness day," says Kirsch.

What to do:
20 minutes of cardio activity

"Then, if your arms need more sculpting than other areas of your body, repeat Tuesday's workout. If your back and shoulders feel especially weak, do Wednesday's workout. If your butt, legs, and abs need even more work than they got on Monday and Thursday, do Monday's workout again," says Kirsch. "This way, you won't be repeating the same moves you did yesterday, which can be tough on your muscles."

What to eat:
Want to drop a few pounds, too? Here are some things to consider when planning your meals this month:

Do make lean protein the main part of lunch and dinner. Do pick dark leafy greens, such as spinach, when choosing vegetables, instead of starchy potatoes. Do avoid alcohol, which contains a lot of sugar, whenever possible. Don't consume too many high-calorie tropical fruits, such as pineapples, bananas, and coconuts. Don't indulge in a lot of sugary desserts. Try satisfying your sweet tooth with fruit sorbet.

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