Last year, American women spent nearly $100 million on creams, lotions, and other topical treatments in hopes of eradicating cellulite from our thighs and butts. We're going to make a wild guess that very few of those products worked as well as you'd hoped. That's because, despite its infamy, cellulite is just plain old fat (albeit dressed up in slightly more offensive attire), and a key to minimizing it is to drop pounds, according to a 2006 study published in the journal Plastic and Reconstructive Surgery.

But how you lose weight matters: Crash dieting can make cellulite worse by reducing skin's elasticity, making more of those little puckers noticeable. Gradual weight loss (to better preserve skin's suppleness and reduce fat) accompanied by targeted muscle development, which firms and smooths underlying tissue, is the most effective cellulite solution, says Glynis Ablon, M.D., an assistant clinical professor of dermatology at UCLA.

When Wayne Westcott, Ph.D., co-author of No More Cellulite (Perigee, 2003), tested such a strategy on 115 women, all of them reported a reduction in cellulite appearance at the end of 8 weeks, and ultrasound measurements confirmed a higher proportion of muscle to fat in their thigh areas.

Now, it's your turn. This comprehensive exercise and eating plan—based on Westcott's findings—will burn fat, build muscle, and shed pounds safely. We know it's not as easy as applying a cream. But it's more effective. See for yourself.

The workout: A science-based, fat-blasting plan for a firmer butt and sleek thighs.

This two-pronged exercise program helps minimize the lumpy, bumpy appearance of cellulite. Aerobic exercise like walking and running burns fat, while lower-body moves such as squats and lunges build muscle.

To maximize fat loss, you'll do 200 minutes of cardio a week—the amount found to produce the greatest weight loss—including high-intensity exercise to rev your calorie burn for up to 19 hours after a workout. You should see the slimming, smoothing results in four weeks!

The expert: Chris Freytag, contributing fitness editor and creator of Prevention's "Fight Cellulite Fast!" DVD, designed these workouts and models the moves.

Your plan at a glance

Part 1: Burn off cellulite (five days a week)

Blast fat with two types of cardio routines: Intense Workouts (an interval program that builds from fitness walks to calorie-blasting runs) and Moderate Workouts (any aerobic activity you enjoy).

Part 2: Tone, smooth, and firm (three days a week)

Tone your muscles by doing six strengthening moves. (Take a day off between these workouts.)

• Weeks 1-2: Do one set of 12 repetitions of each exercise.
• Weeks 3-4: Repeat the circuit twice so you're doing two sets of each exercise.
• Weeks 5-8: Repeat the circuit three times, so you're doing three sets of each exercise. On the third set, instead of holding each move, pulse for three counts by lifting and lowering a few inches before returning to the start position.

PART 1: BURN OFF CELLULITE

Week 1

• Intense workouts (three days a week)
• Brisk walk interval, two minutes; run interval*, one minute
• Number of intervals: 10
• Total workout (five-minute warm-up, five-minute cool-down included): 40 minutes
• Moderate workouts (two days a week)
• You choose: walking, swimming, or cycling, 40 minutes

Week 2

• Intense workouts (three days a week)
• Brisk walk interval, one minute; run interval*, one minute
• Number of intervals: 15
• Total workout (five-minute warm-up, five-minute cool-down included): 40 minutes
• Moderate workouts (two days a week)
• You choose: Walking, swimming, or cycling: 40 minutes

Week 3

• Intense workouts (three days a week)
• Brisk walk interval, one minute; run interval*, two minutes
• Number of intervals: 10
• Total workout (five-minute warm-up, five-minute cool-down included): 40 minutes
• Moderate workouts (two days a week)
• You choose: Walking, swimming, or cycling: 40 minutes

Week 4

• Intense workouts (three days a week)
• Brisk walk interval, one minute; run interval*, four minutes