But that hasn't stopped her from launching a career in MMA with Japanese promotion Rizin, where she is undefeated in three fights.
A nine-time world champion Brazilian Jiu Jitsu black belt, Garcia is the protege of one of the greatest fighters in UFC history, Anderson Silva.
"(She's a) big girl (with a) big heart," Silva told TMZ before Garcia's debut last year.
"(She's) strong, fast, smart. I think Gabi has a great chance to be the best fighter in Japan. I think Gabi is the new generation for MMA fighters."
Before stepping into the ring for her first MMA fight against Tongan-American professional wrestler turned fighter Lei'D Tapa last New Year's Eve, Garcia had only competed in BJJ - where competitors grapple on the ground but don't strike.
Her inexperience in stand-up showed immediately as Tapa landed a big overhand left and knocked Garcia to the mat.
The 30-year-old managed to recover and finish the fight via TKO in the first round but she'd learnt her lesson. "I didn't go through an amateur fight or a small promotion like any other girl in the United States. I went straight to the big leagues," she told MMAFighting.com. "I was so excited I forgot about everything. I got knocked down 11 seconds into the first round."
Garcia followed that by submitting Anna Malyukova by armbar before applying an Americana lock to Destanie Yarbrough at the Saitama Super Arena on the weekend to maintain her perfect record.
Garcia's imposing physique has led to many whispers about the source of her size, particularly given the reputation of Rizin, and its predecessor Pride, for being lax with drug-testing.
Long-time UFC commentator Joe Rogan said Garcia was "clearly taking male hormones" on his podcast earlier this year and argued it created a grey area around her gender - for her and her opponents.
"Where does that fit in? Because if you're fighting against women - and you're fighting against women who are taking nothing but you're taking male hormones - where is this line? Is it penis-vagina, is that the only line? Or is there a certain amount of hormones you take where you become a f***ing dude?" Rogan said.
Garcia has tested positive for a banned substance once, at the 2013 IBJJF World Jiu-Jitsu Championships. But after having the fertility drug clomiphene found in her system, she was found to have not been at fault for the positive test and received no suspension.
A couple of years ago, Garcia was involved in a war of words with Ronda Rousey, after the UFC star claimed she could defeat "any BJJ girl in the world, any weight division, gi or no gi, black belt all the way, in any rule set that they want".
Garcia, and many of her BJJ counterparts, felt disrespected by the claim, but the reality is the huge size difference between her and Rousey will prevent them from ever sharing the ring (or Octagon).
The other woman most often mentioned as the greatest fighter on the planet, Cris Cyborg, is closer to Garcia in size but still significantly smaller.
But that hasn't stopped the two countrywomen from training together - and Garcia is in no doubt about who is the more talented fighter.
"She has her sparring partners at her weight and I have mine, of course, but we train together sometimes. She's surreal. She's a monster," said Garcia, declaring training with Cyborg was harder than training with some men.
"When I throw a jab and the guy responds, I get punched hard. When I throw a jab at Cris, she fires back with a jab, two uppercuts and kicks. She hits as hard as a man. I hit her twice and she comes back with 10 punches (laughs), and I don't see where they are coming from. Cris is so fast. She hits you five times, and the last one is to drop you ... There's no woman in this world that can beat her. Cris is the best fighter in the world."