The observation that the gluteal region appears smaller is traced back to changes in the two primary components defining its size: the gluteal muscles and subcutaneous fat. The muscles, particularly the large gluteus maximus, contribute to shape and volume, while the overlying fat provides the rounded contour. A reduction in size is a common physiological change, typically resulting from shifts in lifestyle, metabolism, or hormones. These changes signal that the body is adapting to new conditions.
Changes in Activity Levels and Muscle Mass
The gluteal muscles—maximus, medius, and minimus—are the largest and most powerful muscle group in the human body, making them highly responsive to changes in physical activity. A decrease in size can be a direct result of muscle atrophy, which is the reduction in muscle fiber size due to insufficient mechanical tension or lack of use. This can occur when a person transitions from a strength-training routine to primarily low-intensity cardio or adopts a more sedentary lifestyle involving prolonged sitting.
When mechanical stress on the muscle is removed, the process of protein synthesis needed to maintain muscle mass slows down. Studies involving extended periods of unloading, such as bed rest, show that the volume of the gluteal muscles can decrease significantly. This loss of lean tissue directly translates to a noticeable reduction in the physical dimension and firmness of the area.
Targeted resistance exercise, such as squats or lunges, is necessary to provide the mechanical load that signals muscle fibers to grow or, at least, to maintain their current size. If an individual has stopped challenging the gluteal muscles with sufficient intensity, the body simply sees no reason to expend the energy required to keep that large muscle mass. The resulting atrophy is a metabolically efficient adaptation to a lower activity level.
Systemic Body Fat Loss and Distribution
The other major factor contributing to the size of the gluteal region is the subcutaneous adipose tissue, or fat, that sits just beneath the skin. When the body is in a sustained caloric deficit, it mobilizes stored fat from various depots across the body for energy. Because the gluteal-femoral region is a substantial fat storage area, any overall body fat loss will naturally include a reduction in this area.
The rate at which fat is lost from a specific area, however, is determined by genetics and the unique metabolic characteristics of that fat depot. The gluteal-femoral fat is considered part of the “gynoid” fat pattern, which is metabolically distinct from the visceral fat stored around the abdominal organs. Gluteal fat cells are often less lipolytically active compared to abdominal fat, meaning they are sometimes more resistant to fat mobilization, but they are not immune to systemic fat loss.
It is not possible to “spot reduce” fat from a single area; fat loss is a whole-body process. Therefore, if a person is dieting, increasing aerobic exercise, or has experienced a significant change in appetite or energy expenditure, the reduction in gluteal size is an expected outcome of a drop in overall body fat percentage.
Hormonal Shifts and Natural Aging
Changes in body composition, including gluteal size, can occur irrespective of diet or exercise due to hormonal fluctuations. In women, the sex hormone estrogen plays a role in promoting the storage of subcutaneous fat in the hips, thighs, and buttocks, contributing to a characteristic body shape.
As women approach and enter menopause, the natural decline in estrogen levels often triggers a shift in fat distribution patterns. Fat storage tends to migrate from the gluteal-femoral area toward the central abdominal area, resulting in a loss of volume in the former region even if total body fat remains constant.
Beyond hormonal shifts, natural aging is also accompanied by a process called sarcopenia, which is the progressive and involuntary loss of skeletal muscle mass and strength. This age-related decline affects all muscles, including the gluteal group, and contributes to a gradual reduction in size over time unless actively counteracted by resistance training.
When to Consult a Professional
While a decrease in gluteal size is typically a benign result of muscle atrophy or intentional weight loss, rapid or unexplained changes warrant medical attention. Losing more than 5% of body weight within a six-to-twelve-month period without any change to diet or exercise routine is generally considered unexplained weight loss and should be investigated by a healthcare professional.
Consult a doctor if the size reduction is accompanied by other concerning symptoms. These accompanying symptoms can occasionally signal an underlying medical condition, such as a thyroid issue or a digestive disorder, that is causing unintentional muscle or fat wasting.
- Persistent fever
- Chronic fatigue
- Night sweats
- Changes in bowel habits
- Difficulty eating