While everyone is born with a genetically determined body type -- for example, a pear, apple or banana shape -- lifestyle modifications like diet and exercise can slightly change the shape of your physique. Tweaking your diet to gain weight and filling out your frame with muscle tissue can give you a curvier appearance, though exactly how curvy you'll look at the end depends on your underlying body type.
Cinch Your Waist With Abdominal Exercises
Make abdominal exercise a key part of your exercise routine. Not only do many abdominal exercises improve your alignment and posture, so you can stand and sit up straight to look more confident, but they can also cinch and compress your waist to give you more of an hourglass figure.
Perform exercises like side planks, wood chops and lunges with side twists. These work your oblique muscles, including the corsetlike internal obliques that help define your waistline. Practice several plank variations -- elbow planks, one-legged planks, walking planks and plank jacks -- to tone your transverse abdominals. This muscle wraps around your waist and works to compress your internal organs, so strengthening it can flatten your abs and cinch in your waist.
Build a Curvier Butt and Hips
You can also create curves on your lower body by building up the muscles in your hips, butt, thighs and calves. Squats and lunges work all the muscles of your lower body -- as well as your abs and back -- and you should include several variations of these exercises to work your lower body from different angles. Try plie squats, goblet squats and squat jumps, as well as side and curtsy lunges, which particularly tone your outer hip and inner and outer thighs. And perform dead lifts and Romanian dead lifts to tone your hamstrings and glutes -- these exercises help create that definition between your thighs and butt, so your glutes look perkier. Build up your glutes even more with hip thrusts and glute bridges, using a barbell placed across your hips for added resistance. And add sexy curves to your calves with standing calf raises, holding dumbbells for more resistance.
Support Your Weight Gain With Diet
You'll also need to adjust your diet to gain weight. A healthy diet will help fuel your workouts, and it will provide nutritional support for muscle growth that will help you gain curves. Aim for slow weight gain of roughly 1/2 to 1 pound weekly, which you can achieve by eating 250 to 500 calories extra each day. If you're currently maintaining your weight, simply add the extra calories to your existing meal plan; if you've been losing weight, use an online calorie-burn estimator to figure out how many calories you need, then add 250 to 500 to that number.
Your diet should come from healthy whole grains and lean proteins like tofu, eggs, chicken and fish, as well as fruits and veggies, legumes, nuts, seeds and dairy. Pay particular attention to your protein intake -- strength training increases your protein needs, so you should multiply your weight in pounds by 0.8 to get your daily protein requirement. For a 125-pound person, that means 100 grams of protein each day. Boost your protein intake by serving eggs for breakfast, including grilled chicken or a cup of lentils or beans in your lunch, snacking on almonds or low-sodium turkey jerky and enjoying salmon, tofu or tempeh at dinner.
Set Realistic Goals
Start your fitness journey off on the right track by setting realistic goals for your progress. A well-planned strength routine will allow you to strategically build up muscle to help you gain curves, but your body type will limit how curvy you'll look as you progress with your workout plan. If you naturally have a lithe, supermodel-esque figure, you won't be able to achieve a highly curvy figure with lifestyle changes -- but you can make yourself look slightly more curvy, as well as fit and healthy.
Keep in mind, too, that sexiness is about more than just meeting certain body standards. As you get fitter, focus on how healthy, strong and empowered you feel -- that confidence will radiate and make you look sexier.