To reduce your waist size without losing any weight, you should understand the difference between muscle tissue and fat. Muscle takes up less space than fat but doesn't weigh any more or less. Reducing your body fat while increasing your muscle tissue will help reduce your waist but your weight will stay the same. Muscle tissue requires a lot of energy to sustain itself and because of this your metabolism will stay activated even when you are resting. You will be able to eat more and still maintain the same weight.
Provide your body with regular small meals so your blood sugar levels stay stable and your are less likely to get hungry and crave fattening foods. Divide your three large meals of the day in half to create six smaller meals to consume throughout the day.
Perform cardiovascular exercise five days per week for a minimum of 20 minutes per day. Bring the heart rate and metabolism up to burn fat from your entire body, including stomach fat. Go jogging, walking, bicycling or play racquetball or tennis.
Add strength training to your workout routine to build muscle tissue on three alternate days of the week. Do compound exercises that train multiple muscles at the same time, for optimal muscle growth. Include weighted lunges, squats, dead lifts, bench presses, push-ups and rows. Focus on training the large muscles -- back, chest, upper legs, triceps, and biceps -- first. Train the smaller muscles -- hips, arms, calves and shoulders -- afterward. Work your abdominal muscles last with targeted exercises such as crunches, reverse crunches and side bends.
Learn how to do the stomach vacuum exercise. Bodybuilding.com states that this exercise can take 2 to 4 inches off your stomach in three weeks.
Stomach vacuum exercise: Stand up straight and exhale all the air from your lungs. Pull in your tummy and envision pulling your bellybutton to your spine. Breathe normally as you hold the tension in your stomach. Do three sets of the exercise per day, on three non-consecutive days of the week. Suck your stomach in for 20 seconds during each set on the first week. Increase the time to 40 seconds per set during the second week and 60 seconds per set throughout the third week.
Wear shape enhancing underwear that tucks in your tummy and makes your waist appear smaller. Spanx is a brand that provides tummy-control underwear for both men and women.