The Mysterious Math Behind the Brazilian Butt Lift

In the history of gluteal enhancement, Mexico City stands out. It protrudes. It was here, successful 1979, that a integrative surgeon, Mario González-Ulloa, archetypal installed a brace of silicone implants designed specifically for the buttocks. The textbook Body Sculpting with Silicone Implants calls González-Ulloa the “grandfather of buttock augmentation.” The aboriginal 2000s saw a caller procreation of Mexico City buttock translation luminaries, notably Ramón Cuenca-Guerra. In his 2004 insubstantial “What Makes Buttocks Beautiful?” Cuenca-Guerra laid retired 4 characteristics that “determine charismatic buttocks” arsenic good arsenic the 5 types of “defects,” with strategies for correcting each one. I, for instance, person defect benignant 5, the “senile buttock.” (González-Ulloa’s depiction of this took the signifier of charcoal nudes contrasting “the emblematic ‘happy buttock’”—high, rounded, dimpled—with its counterpart, the low-slung, drooping “sad buttock.”)

While I recognize the worth of standardizing procedures and mounting guidelines for surgical practice, I tripped implicit Cuenca-Guerra’s methodology. How and by whom had the determinants been determined? Like this: 1,320 photographs of “nude women ages 20 to 35 years, arsenic seen from behind” were presented to a sheet of six integrative surgeons, who “pointed retired which buttocks they considered charismatic and harmonious, and features connected which this attractiveness depended.” Oho!

I thought it would beryllium absorbing to speech to Cuenca-Guerra astir the conception of a visually perfect pistillate figure. As thing that could oregon should beryllium surgically created (or, successful the lawsuit of the senile buttock, re-created). As thing that adjacent exists. I sent an email utilizing the code connected a much caller diary paper. There was nary reply. Ramón Cuenca-Guerra’s buttocks are successful worse signifier than mine. He has been dormant for immoderate time. I was capable to scope a workfellow of his, José Luis Daza-Flores. Here was the 3rd generation; conscionable arsenic Cuenca-Guerra had studied nether González-Ulloa, Daza-Flores had studied nether Cuenca-Guerra, extending the lineage and making Daza-Flores, I guess, “the lad of buttock augmentation.”

Daza-Flores collaborated with Cuenca-Guerra connected a insubstantial called “Calf Implants,” successful which the squad did for the little limb what Cuenca-Guerra had done for the butt: laid retired “the anatomical characteristics that marque calves look attractive” and the “defects” to beryllium addressed. Here again, integrative surgeons were recruited to justice images—2,600 of them, a immense photographic millipede of pistillate legs.

The insubstantial took an unexpected turn. Referring to a marked-up photograph of a little limb deemed attractive, the authors tried to amusement that its measurements conformed to what is known successful mathematics arsenic the divine proportionality (or aureate ratio)—1.6 (I’m rounding it off) to 1. When you disagreement a enactment into 2 parts specified that the full magnitude divided by the agelong portion is adjacent to the agelong portion divided by the abbreviated part, some those ratios volition beryllium 1.6 to 1. I recovered an illustration of the divine proportionality connected a website called Math Is Fun (and convincing nary one). The aureate dividing enactment splits the magnitude specified that 1 chunk is astir two-thirds and the different is astir one-third. The past Greeks divided the “ideal” look into likewise proportioned thirds. This was the archetypal clip I’d seen the divine proportionality applied to a leg.

The insubstantial contained sentences similar this: “Seventeen women had bladed legs, successful the signifier of a tube, and a specified 1:1.618 ratio successful the A-P and L-L projections.” Though I confess to not grasping the particulars of the discussion, I judge that to beryllium a mathematically precise statement of cankles.

The insubstantial besides cited the Fibonacci sequence, a progression of numbers wherein each successive fig opening with the 2nd 1 is the sum of the erstwhile two. It goes similar this: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 . . . And, opening with 5 and 3, if you disagreement 2 successive numbers alternatively of adding them—21 implicit 13, say, oregon 13 implicit 8—you volition ever get, ta-da, the divine proportion: 1.6.

The Fibonacci series turns up with immoderate regularity successful nature. You tin find it successful the turnings of the spiral traced by the interior chambers of the nautilus ammunition arsenic it grows, oregon the maturation way of sunflower seeds—two commonly cited examples. (Less commonly: the branching signifier of the sneezewort plant.) In humans, it’s seemingly not conscionable calves. Calculator-happy physicians and researchers person published papers purporting to amusement the aureate ratio successful the comparative lengths of the bones of a finger, the proportions of incisors successful narration to canine teeth, the structures of aortic valves and the branching of the coronary arteries, the dimensions of the uterus astatine highest fertility, “optimal nipple position,” and the helices of DNA.

It is an intriguing, if not wholly convincing, notion: that mathematics defines beauty.

When I wrote to Daza-Flores, helium confirmed that erstwhile helium transfers abdominous to the hips and buttocks, helium follows the Fibonacci sequence. I pictured him with a purple surgical marker and a ruler, drafting arcs and equations connected an anesthetized torso. How was helium coping with what those successful his tract notation to arsenic “the Kardashian movement”: the surging request for rear ends that autumn good extracurricular the Fibonacci ideal?

The integrative country session of José Luis Daza-Flores is connected a residential broadside thoroughfare successful a pleasant Mexico City vicinity called Noche Buena. The gathering besides contains a time spa and a cosmetic dentist, but thing astir its exterior suggests the upscale beautifying that goes connected inside. The waiting country seems designed to calm alternatively than to impress. The seating is comfy and the country is quiet, the clamor of a Mexico City weekday replaced by synthesized instrumental euphony and the occasional hushed spritz of a wall-mounted scent dispenser.

The deficiency of ostentation is successful enactment with my content of the surgeon himself. He is courteous, soft-spoken, deferential. This is simply a antheral who says “por favor” to Alexa erstwhile helium wants to alteration the euphony successful the operating room. When helium speaks with patients successful the waiting country oregon earlier surgery, I’ve seen him scope retired to instrumentality their hand.

It’s 8:15 americium now. Daza-Flores sits successful the clinic’s kitchenette, dressed successful scrubs, having an espresso portion the morning’s diligent is prepped for country down the hall. He looks young for his age, but not worked on. I don’t spot immoderate of what his ilk similar to telephone “defects.”

From a folder, I descent retired Cuenca-Guerra’s “Beautiful Buttocks” paper.

In the astir respectful mode possible, Daza-Flores distances himself from the work. Cuenca-Guerra, helium says, acrophobic himself with the placement and size of buttock implants, but helium overlooked the sides of the hips. It is this lateral projection that, coupled with a comparatively smaller waist, creates the classical hourglass figure. You tin marque a brace of butt cheeks protrude from present to Puerto Vallarta, but it won’t alteration the patient’s fig viewed head-on. It won’t marque an hourglass retired of a gramps clock.

In 1973, a fewer years earlier Dow Corning worked with González-Ulloa to plan the archetypal cosmetic buttock implants, Tennessee surgeon William Cocke pushed a brace of silicone implants nether the tegument connected the flanks of a pistillate who was “quite acrophobic astir her underdeveloped hips.” The results were described successful 1 textbook arsenic “less than optimal.” Likely this was due to the fact that implants placed superficially—beneath the tegument and fat, alternatively than nether oregon betwixt muscles—tend to shift, and their contours are often disposable done the skin. (In his writeup of the results, Cocke mentions nary of this, noting simply that “the diligent has since married.” As though constrictive hips had stood successful the mode of matrimonial bliss.)

“To reshape this lateral contour you request fat,” Daza-Flores says. He gets up and takes a vessel from the refrigerator. The timing makes maine deliberation for a infinitesimal that he’s retrieving a vessel of quality fat. It’s not, of course. It’s papaya. He sets it connected the array betwixt us. “Fat transfer,” helium continues. That is, suctioning abdominous from 1 country and injecting it someplace else. The method is known mostly arsenic liposculpture. Specifically and casually, erstwhile applied to the nether country (with oregon without implants), it’s a Brazilian butt lift.

“So the country has changed,” helium says, “but the conception of divine proportions has remained.”

I inquire Daza-Flores if helium tin amusement maine immoderate examples of aureate ratio divinity among his patients. He scrolls done photographs connected a laptop. Lots of TikTok stars and quality influencers. “These are beauteous adjacent to perfect proportions,” helium says. Here’s the thing, though. Their befores look beauteous perfect too. In 2021, a squad of Norwegian and American integrative surgeons published a insubstantial with the subtitle “Golden Proportions successful Breast Aesthetics.” Here’s what stood retired for me: Out of 37 subjects, lone 5 had breasts that conformed to the aureate ratio. (An further 4 had 1 aureate breast.) “Neither bosom was considered optimal for 28 (76 percent [of the]) subjects.” The highest aesthetic ranking belonged to a “virtual subject”—a computer-generated torso. Plastic surgeons and their patients are chasing an perfect that seldom exists successful undoctored quality anatomy. The much enactment quality influencers get done, either surgically oregon done TikTok filters, the shittier the remainder of america consciousness astir our utterly normal-looking bodies and faces.

And here’s the different thing: By now, the desired look has eclipsed adjacent Fibonacci’s ideals and wandered into the realm of cartoon, of anime.

Before I left, I printed retired a bid of photographs from the London tabloid The Sun, purporting to amusement Kim Kardashian from down successful a thong bikini bottom. The woman’s buttocks and hips dwarf the remainder of her legs, a “defect” referred to successful an Aesthetic Surgery Journal insubstantial arsenic the “lollipop deformity,” oregon “marshmallow connected a stick.”

“That to maine is not beautiful,” Daza-Flores allows. With his fork, helium indicates the fold astatine the bottommost of the woman’s butt cheeks. “It’s excessively long, and excessively creased.” The intragluteal fold, arsenic it is professionally known, should, helium says, beryllium much of a gentle ravine and widen nary much than a 3rd the width of the buttock. The folds of Alleged Kim’s traverse the full cheek. “It looks similar a dense buttock.”

A pistillate with double-D bosom implants is hefting 4 pounds. When women kick of sagging breasts, Daza-Flores volition suggest a assistance alternatively than implants. “If you usage an implant—for astir six months the bosom volition look nice, but yet it volition autumn down worse than before.”

Daza-Flores slides the printout backmost to me. “She has everything you tin get, each astatine once. Implants, abdominous transfer, injections of Sculptra,” helium says, referring to a filler. “She’s astir apt getting thing each six months. And girls inquire for that. They say, ‘I privation the Kardashian surgery.’”

And who wins? Fibonacci oregon Kardashian?

“I effort to suggest not going that far,” Daza-Flores says. He tries to get wrong their heads, to spot wherefore they’re asking for this. Is it thing their spouse wants? He counsels patients against getting implants to delight idiosyncratic else. Because, arsenic helium puts it, the surgeries often outlast the relationships. He has had patients who’ve “changed retired their bosom implants each clip they alteration boyfriends.”

He besides reminds patients that the look is simply a trend, and similar each trends, it volition fade. (Indeed, 2 years later, erstwhile I instrumentality to this section earlier going to print, the American Society of Plastic Surgeons is reporting an Ozempic-fueled inclination for a leaner “ballet body.”)

Daza-Flores drains his cup. “If I don’t bash it, they’ll bash it anyway. They’ll spell with different MD.” Often, that MD is not a board-certified integrative surgeon. It whitethorn beryllium an aesthetician oregon a wide practitioner who got a certificate done an online course. Daza-Flores calls them “nomads,” due to the fact that erstwhile the lawsuits commencement to accumulate, they determination to different state. One mode to justice practitioners, helium says, is to spot however agelong they’ve been practicing successful the aforesaid location.

Daza-Flores won’t beryllium utilizing buttock implants of immoderate size connected this morning’s patient, lone abdominous transfer. Lately he’s been utilizing implants little often. The Brazilian works that manufactures his preferred marque burned to the ground, and different companies person been having occupation obtaining oregon renewing their import licenses. Daza-Flores suspects corruption: authorities officials demanding exorbitant fees and bribes.

But the main crushed is that José Luis Daza-Flores loves to enactment with fat.

Medical instrumentality catalogs fascinate me. It ne'er seems to hap to the radical who sanction the instrumentality and constitute the transcript that anyone but a doc volition beryllium browsing the offerings. Would you different sanction your liposuction cannula The Fat Disruptor? The Bayonet Infiltrator? Clearing the way for the cannula is the “punch,” which, successful the words of the Black & Black Surgical catalog writer, “make[s] the archetypal stab wound.”

That’s done now, and the cannula is in, nosing astir the patient’s little back. The to-and-fro of liposuction looks precise overmuch similar the question utilized to wield that different wanded suction appliance. But quicker and much vigorous. More similar mopping than vacuuming.

Daza-Flores waits for maine to decorativeness nattering. “Grating cheese. That’s what it feels like,” helium says.

Because 20 percent of the suctioned abdominous is blood, the worldly moving done the tubing is acheronian pinkish alternatively than yellow. This, combined with the abdominous postulation canister’s resemblance to a blender, makes it look that Daza-Flores is extracting raspberry smoothie from his patient. His wife, besides an MD, had disquieted that I mightiness faint oregon consciousness sick astatine the show of abdominous being sucked from a body. If anything, it’s making maine hungry.

Once the raspberry dainty begins to capable the canister, humor cells and serum settee out, leaving a furniture of abdominous above. Daza-Flores uses the verb decant, which adds a interaction of people to the proceedings. Some surgeons usage a centrifuge to abstracted retired the fat, but Daza-Flores feels that the forceful spinning tin harm oregon destruct the cells. Even with the gentler treatment, astir fractional the injected abdominous cells volition dice and beryllium absorbed by the body.

The abdominous Daza-Flores loves astir is the abdominous astir of america hate. Love handles. The blub astatine the waistband. “This is the fantastic fat,” helium is saying. He loves it for the crushed we hatred it: it is stubbornly persistent. If a idiosyncratic diets, it’s often the past abdominous to disappear. If they commencement to regain weight, that’s wherever the abdominous archetypal appears. In liposculpture, Daza-Flores moves the recalcitrant backmost blub cells distant from wherever they’re unwanted and installs them wherever they’re wanted. “The familial accusation remains,” helium says. Now if a diligent puts connected weight, it doesn’t amusement up arsenic backmost blub but arsenic curvaceous hips and blessed buttocks. Donor dominance!

For this aforesaid reason, Daza-Flores ne'er uses backmost blub to capable retired parts of the face. “If you instrumentality it from down here, and past they summation weight, the cheeks get fat.”

Almost done. The cannula has widened the wounds made by the punch. They look similar tiny slots, arsenic though the pistillate has USB ports. An adjunct switches retired the cannulas, from aspiration to injection. In all, astir 6 quarts of abdominous person been sucked from the patient, 2 of which volition present beryllium injected successful her buttocks and the sides of the hips. This is wherever Fibonacci steps into the room. Daza-Flores starts astatine the extracurricular flank, spirals down and around, and ends up astatine the halfway of the buttock. He likens the way helium follows to the spiral of a snail shell, yet different illustration of Fibonacci numbers successful nature. I had imagined him moving from calculations, plotting points of the curve connected the patient’s skin. By now, helium says, helium tin eyeball it.

The injection cannula has a plunger, which Daza-Flores squeezes arsenic helium guides the instrumentality backward. If you could spot beneath the skin, it would look similar idiosyncratic decorating a cake. With quality fat. Happy birthday! He pauses astatine the acme of the patient’s near buttock.

“Mira. This is simply a unsafe area.” Underneath the gluteal muscles are respective ample humor vessels. Even tiny amounts of abdominous successful the circulatory strategy tin spell trouble, successful the signifier of a “uniformly fatal abdominous embolism.” I’m quoting a 2018 Australasian Society of Aesthetic Plastic Surgeons property merchandise entitled “The Brazilian Butt Lift Named arsenic the Most Dangerous Cosmetic Procedure.” An embolism is simply a clot that breaks escaped and gets stuck successful a constrictive humor vessel, blocking the travel of blood. If it lodges successful the bosom oregon encephalon oregon lungs, that’s superior trouble.

“There were a batch of deaths,” Daza-Flores says. “A batch of girls dying from abdominous transfer. We didn’t recognize what was happening.” Daza-Flores was portion of a task unit that reviewed the autopsy reports. In each case, abdominous was recovered successful the muscle. Rather than keeping the injection cannula much oregon little parallel to the muscle, immoderate practitioners were aiming down into it. Even if the space was conscionable 10 oregon 15 degrees off, Daza-Flores says, it was capable for the abdominous to participate the information zone.

“They support dying, to archer you the truth. Probably erstwhile a period present successful Mexico City. Even now, radical are inactive doing it, injecting into the muscle. There are clandestine clinics with poorly trained oregon untrained aestheticians.” It happens successful the United States arsenic well. Women were dying successful Miami truthful often that successful 2019, the Florida Board of Medicine issued an exigency ruling. Florida Administrative Code R 64B8–9.009(2)(f) prohibits the injection of abdominous into oregon beneath the gluteal muscles.

I person to say, the diligent looks great. Though successful my estimation, she looked large erstwhile she walked into the waiting room. I enactment everyone’s close to bash to their assemblage immoderate makes them consciousness bully astir themselves, but it would beryllium beauteous if feeling bully astir oneself didn’t beryllium connected altering the mean effects of aging. Particularly erstwhile the alterations impact the risks of large surgery. Interestingly, a bulk of the surgeons successful the aforementioned survey of surgeons and patients and breasts seemed to consciousness the same. The surgeons, 45 successful all, were asked to ideate that a pistillate spouse oregon acquaintance had travel to them expressing dissatisfaction with the size of their breasts. Would they urge getting implants? Sixty-one percent said no.

Let’s spot astir this one. “Dr. Daza-Flores, what would you accidental to your ma if she wanted you to bash a full-torso liposculpture connected her?”

He laughs. “I already operated connected my mom.” He extracts the cannula and hands disconnected the bare syringe. “My ma loves surgeries!” He turns to the assistant. “Remember? We did the tummy tuck? But we didn’t bash abdominous transfer.”

I callback what helium said astir embolisms. “Because of the risks?” “Because she didn’t privation it. She doesn’t request it!” An adjunct hands him a caller syringe of fat. “She’s got a precise large butt.”

“Mira! I’m making a fossette.” Fossette is the aesculapian connection for dimple. A acceptable of supragluteal (above the buttocks) fossettes is 1 of Cuenca-Guerra’s 4 “determinants of gluteal beauty.” Daza-Flores presses his forefinger into the woman’s soma to support the abdominous from filling successful that spot, archetypal 1 side, past the other.

He steps backmost to measure his work. Removing the abdominous supra the buttocks has fixed the diligent a much defined waist and a longer-looking back. Bringing the torso person to the aureate ratio: two-thirds backmost and one-third ass. He makes a last sweep. The cannula moves astir nether the tegument similar a limb nether a bedsheet. There are sounds, recognizable ones—sounds of sloppy eating, of things pulling up retired of mud. I’m some disgusted and piteously envious.

Excerpted from Replaceable You: Adventures successful Human Anatomy. Copyright 2025 by Mary Roach. Used with support of the publisher, W. W. Norton & Company, Inc. All rights reserved.