Luis's 24-year-old mother, Isabel Pantoja, wasn't initially concerned about her son's weight gain, but became alarmed when she realized Luis far outweighed his brother Mario, who is nearly three years older, the Daily Mail reported.
"I thought it was because I had good breast milk," Pantoja, who is from Colima, Mexico, told the Daily Mail.
When Luis was first born, he weighed a normal eight pounds. At two months, he weighed 22 pounds and could only fit into clothes for children already two or three years old. By 10 months, Luis weighed a staggering 62 pounds, and doctors are baffled as to what could be causing him to bulk up so rapidly.
Luis' father, Mario, who works at a local juice plant and is physically fit, finds it exhausting to even carry his young son.
— The African Voice (@teddyeugene) November 11, 2017
Family members take turns pushing Luis in an old push-chair to his hospital appointments four times a week.
"It hurts to watch the nurses search among the rolls of fat on his arms for a vein," Mario said.
One working theory is that Luis could have Prader-Willi Syndrome, a very rare genetic disorder that causes an increase in appetite, obesity, intellectual disability and shortness of stature.
However, Luis eats a normal amount of food for his age, suggesting that Prader-Willi may not be the correct diagnosis, as Prader-Willi patients are constantly hungry.
— Jose Jaimes (@the_mantese) November 12, 2017
Silvia Orozco, a surgeon specializing in nutrition, has a different theory. Orozco suspects that a lack of certain nutrients in Isabela's diet while she was pregnant may have affected the glands in Luis' body that manage metabolism.
If this is the reason for Luis' weight gain, hormone injections could help improve his metabolism.
However, these injections cost $555 each and Luis' father only earns only $197 a month. The family has begun reaching out on social media to raise money for Luis' medical bills.