The Brazilian Butt Lift (BBL) is a body contouring procedure that enhances the size and shape of the buttocks using a patient’s own fat, known as autologous fat grafting. The procedure involves harvesting fat cells from areas like the abdomen or thighs via liposuction and then transferring the purified cells into the buttocks. The success of a BBL is directly tied to how many of these transferred fat cells establish a new blood supply and survive in their new location. The rate of fat retention is the primary concern for patients seeking a long-lasting and predictable result.
The Typical Range of Fat Retention
The amount of transferred fat that permanently survives the BBL procedure typically falls within a range of 50 to 80 percent. This wide variation is normal and accounts for the biological reality that some fat cells will not successfully integrate into the new tissue environment. To compensate for this anticipated loss, surgeons generally inject a larger volume of fat than is ultimately desired, a technique called overfilling.
The final, permanent result is not immediately visible after the surgery. Initial results appear much larger due to overfilling and significant post-operative swelling. The body naturally begins to reabsorb the non-viable fat cells in the weeks following the procedure. It takes approximately three to six months for the swelling to fully subside and for the surviving fat cells to stabilize. Only after this stabilization period can the final, retained volume be accurately assessed.
Factors Influencing Long-Term Fat Survival
The percentage of fat that survives long-term is highly dependent on technical factors during the surgery and the inherent quality of the fat cells themselves. Gentle liposuction techniques, such as those that use low-pressure vacuum systems, are preferred to minimize trauma to the delicate fat cells. Excessively aggressive harvesting can rupture the cells, significantly diminishing their viability before they are transferred.
Fat processing is another important technical step, aimed at purifying the harvested fat by removing blood, excess fluid, and damaged cells. Common purification methods include decanting, washing with saline, and centrifugation. Controlling the speed and duration of centrifugation is necessary to prevent cell damage.
The recipient site’s health and vascularity also play a role in determining how well the fat “takes.” For the transferred fat to survive, it must rapidly establish a new blood supply, a process called neovascularization. Surgeons promote this by injecting the fat in small, thin layers, which maximizes the surface area contact between the injected fat and the existing, vascularized tissue. This technique ensures that the fat cells are close enough to the surrounding tissue to absorb nutrients through a process called plasmatic imbibition during the first few days.
What Happens to the Fat That Doesn’t Survive
The fat cells that fail to establish a blood supply in the new location are reabsorbed by the body through a natural biological process. The loss of these non-viable cells is expected and occurs primarily within the first three to six months following the BBL.
When fat cells die, their contents, primarily triglycerides and fatty acids, are broken down. Specialized immune cells called macrophages engulf the dead cells, a process known as phagocytosis. The resulting lipids are then transported via the bloodstream, mainly to the liver, where they are metabolized like any other fat in the body.
In some cases, the body may fail to fully metabolize the dead fat cells, leading to potential complications. One such outcome is the formation of an oil cyst, which is a pocket of unabsorbed liquefied fat. Another possibility is fat necrosis, where the dead fat tissue hardens and becomes fibrous. Both of these outcomes are localized reactions to the non-viable fat.
Maximizing Fat Retention Through Post-Operative Care
The patient’s commitment to post-operative care is highly influential in maximizing the long-term survival of the transferred fat cells. The most important instruction is to avoid applying direct, sustained pressure to the treated area for at least two to three weeks. Pressure restricts blood flow, which starves the newly transferred cells of the oxygen and nutrients needed to survive.
Patients must avoid sitting directly on the buttocks and should sleep on their stomach or side for up to two months. When sitting is necessary, a specialized BBL pillow or cushion is used to support the thighs, keeping the weight off the buttocks. Wearing a compression garment as directed by the surgeon helps control swelling and supports the healing tissues.
Nutrition also supports the healing process and fat cell survival. Consuming a diet rich in healthy fats (such as those found in avocados and nuts) and adequate protein supports the body’s repair processes. Staying well-hydrated is important to maintain circulation and help the body clear away waste products. Furthermore, patients must completely avoid nicotine and smoking, as these substances severely impair blood flow and hinder the body’s ability to establish a new blood supply to the graft.