First, we should define what we mean by this talk of pears, apples and peppers. A pear shape - which most women possess - is a physique with a small upper body and a larger lower body. The rarer apple-shaped woman carries fat in the torso area with thinner legs and arms. A chili pepper shape is thin overall.

Chili peppers aside, most women do face an uphill battle in the bodyfat department. "Women have the disadvantage of possessing about 6% more bodyfat than men, most of which lies on the hips and thighs," says Michele S. Olson, PhD, FACSM, CSCS, an exercise physiologist and professor of exercise science at Auburn University Montgomery (Alabama). "Since lower-body fat is hard to mobilize and is heavily under the influence of your genetics - coupled with muscle being harder to build due to less natural testosterone - most women definitely have a unique set of physiologically based challenges to overcome in trying to shape their bodies."

Gender plays a role in bodyfat, but your natural body shape will always rule where the fat is positioned. No matter how hard you try, a pear-shaped woman will always be a pear, an apple-shaped woman will always be an apple, and a very thin person is likely to remain thin, Olson says.

Okay, that's the bad news. But don't get discouraged just yet. While the bodyfat distribution that you've inherited through the family tree over thousands of years might be dispiriting, you can tailor your workout to your bodytype and make a difference in how your proportions appear.

Just how much of a difference is possible? Operating within your genetics and using resistance training, you can change your body's look by about 30%, which is pretty significant. William J. Kraemer, PhD, CSCS, co-author of Optimizing Strength Training (Human Kinetics, July 2007) and professor of kinesiology, physiology, neurobiology and medicine at the University of Connecticut (Storrs), says each person is born with a certain physical structure (like height and bone size) and a certain number of muscle fibers. Those factors will not vary. "You are not going to go from being a petite individual to a very large individual based on muscle," he says. However, the size and shape of your muscles and their appearance in relation to the amount of fat and subcutaneous fat deposits in your body can change with the help of nutrition and exercise.

To use the most common shape as an example, how can you get your pear-shaped body to seem, well, less pearlike? With diet and exercise, such as 5-7 days a week of aerobic activity, you'll see some fat loss. But women have a tendency to overwhelm themselves on the aerobic element, Kraemer notes. "It's a double-edged sword, since doing just cardio inhibits a lot of muscle fibers from getting bigger - especially the Type I slow-twitch fibers," he explains. "They maintain their size while you work on the fat component."

For a woman's body to change, it's often a fight against nature. For instance, if you have a very small upper body, given the number of muscle cells you're born with, upper-body resistance training will only get you so far in developing those muscles.

Women tend to have larger deposits of bodyfat in their hips, thighs and upper arms. When you lose fat, you lose it from all over your body, not just the areas you want to target. But the good news is you'll notice fat loss first in the areas of higher concentration.

To shift your overall proportions, Olson says your best bet is to think of your body as two or three separate zones and then try to increase the size of muscle in smaller bodyparts and decrease the size of larger bodyparts. Using the example of a pear shape, a woman could focus on circuit-type work with cardio on the legs and more pure strength work on the smaller upper-body areas to achieve a balanced look, Olson says. This will help you reduce the size of your lower body and increase the size of your upper-body musculature a bit, for a better-balanced body all around.

If a major transformation is what you're after, you should create an exercise plan based on your bodytype. A pear-shaped woman seeking to have a more balanced body will need to combine cardio and high-rep resistance training on her lower body. For the cardio component, in addition to 2-3 steady pace workouts, include at least one session per week of interval-based cardio exercise (sprint 20 seconds/jog 30 seconds) for 45 minutes. For the upper body, you'll need to hoist heavier weights at a lower rep count, causing the muscle to reach failure. That is, lifting a weight for 10-12 repetitions but being unable to lift the 13th rep, and increase from two to four sets of each exercise. Split your training into upper- and lower-body sessions, doing upper body Monday, Wednesday and Friday and lower body Tuesday and Thursday. An apple-shaped woman would have a different workout. "Women will want to work on their abs, doing something like a Pilates abdominal workout an extra day or two per week," Olson says. For cardiovascular and resistance training, an apple shape should be more balanced in contrast to a pear shape, using a traditional strength-training program for both upper and lower bodies.

If you're flat-out skinny, lift weights four times a week using a split such as chest, triceps and abs on Monday, legs on Tuesday, shoulders and abs on Thursday and back and biceps on Friday. Use heavier weights and higher volume, around 9-12 sets per bodypart. Do lower-intensity cardio for no more than 20 minutes at a time. "Walking three times a week would be plenty," Olson says. Yoga is another option. "Yoga would help a thin person with static strength and balance, which is very important during weight-training workouts that require someone to lift heavier intensities of weight," Olson remarks.

Finally, allow up to six months for the complete transformation to occur. "You need long-term training to really see changes take place," Kraemer comments. "The things you see in TV commercials are probably due to extreme dieting. I've never been able to see something like that in research, where in 10 weeks you look like a completely different person."

As you embark on your shape-specific training program, remember that you'll see some changes in a week or two, but to change your body composition to your ideal is a long-term project. While your natural body shape - pear, apple, chili pepper or some combination of these - will rule, trimming fat with cardio and building up muscles with high-intensity weightlifting will help you achieve a balanced figure. And, if you exercise and eat right to keep everything under your control in check, chances are good that you'll see changes you're hoping for. HERS

When it comes to changing your body shape through fitness and nutrition, your hormones are key in signaling what your body and muscles should do. For instance, they tell the muscle to make more protein and tell enzymes to keep bodyfat, depending on the signal.

"What you're trying to do is get optimal signaling," says William J. Kraemer, PhD, CSCS, professor of kinesiology, physiology, neurobiology and medicine at the University of Connecticut (Storrs).

When you're attempting to revamp your natural body shape, you're breaking down fat and building muscle, not the reverse. But the reverse will happen if you make training and dieting mistakes.

"Catabolic hormones like cortisol give your body a signal to gain and preserve fat and break muscle down if you starve yourself," Kraemer explains. "Without enough food for fuel, the body tries to preserve glycogen, so it will start breaking down tissue to preserve glycogen stores in the liver and muscle."

Additionally, if you have too many glycogen spikes at times other than around your workout, then insulin will reduce your body's enzymes needed to break down fat. "If you're kicking the insulin up all day with high-carb impacts like sports drinks and plain bagels, you won't be able to get rid of that subcutaneous fat," Kraemer explains. So, if you starve, you're hurting your fat-loss chances, and if you don't watch the sugar, fat loss is impaired, too!

Anabolic hormones like testosterone signal the body to build muscle. Even with a high-intensity weightlifting regimen, women will not get bulky like men. The reason? Women have about 10-20 times lower resting concentrations of testosterone than men. Even with very consistent training, a woman just doesn't have enough testosterone to put on too much unappealing bulk.