While standing may help burn slightly more calories than sitting, it is not likely to significantly reduce waist size on its own. Losing fat in a particular area of the body, such as the waist, requires a combination of overall weight loss and targeted exercises.
To lose weight and reduce waist size, it's important to focus on a healthy, balanced diet and regular exercise. This can include a combination of aerobic exercise, such as running, cycling, or swimming, and strength training exercises that target the core muscles of the abdomen and lower back.
In addition to exercise, reducing stress levels, getting adequate sleep, and maintaining a healthy lifestyle overall can also contribute to a reduction in waist size. However, standing alone is unlikely to have a significant impact on waist size without other lifestyle changes.