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Fast Food Probably Won't Make You Grow Man Boobs, But It's Complicated

A Chinese news story claims that a 19-year-old's sizable 'man boob' was caused by eating too much fast food. We asked experts if this is possible.
Photo by Nisian Hughes for Getty Images

It's no secret that a diet heavy in fast food can do a number on your body; from your brain to your heart to your waistline. But could crushing too many burgers really lead to a man growing a single A-cup breast? One Chinese media outlet is making the claim that it can.

According to a recent story from Qianjiang Evening Post as translated and reported by the UK's Daily Mail, a 19-year-old man underwent a mastectomy to remove excess tissue in his right breast, which he claimed began growing when he was 13 as a result of gynecomastia, the swelling of male breast tissue caused by an imbalance of estrogen and testosterone.


The Daily Mail article alleges that "his 'man boob' was caused by the consumption of fast food" and the "gender-bending" chemicals therein. It goes on to quote Dr. Pan Zhongliang, chief physician at Wenzhou Central Hospital, where the mastectomy was performed in early July, advising men to stay away from foods like "fried chicken, soy milk, and royal jelly."

Given our obvious appreciation for fast food here at MUNCHIES, it felt necessary to dig deeper into whether fast food can actually cause breast growth in men. We spoke to Kate Comeau, a dietitian and spokesperson for Dietitians of Canada, who says she's not buying the fast food hypothesis in the case of the man from the Qianjiang Evening Post's story.

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"I can tell you that there is definitely no evidence to link fast-food consumption to gynecomastia," Comeau told MUNCHIES. "[Fast-food consumption] has not been linked to this condition in any published literature; the condition is typically due to an altered estrogen-androgen balance. It can happen in neonate and during puberty or because of drug intake, chronic liver or renal disease, hyperthyroidism, hypogonadism, or testicular or adrenal neoplasms."

Notably absent from this enumeration are French fries and onion rings, though Dr. Pan is not entirely off-track in suggesting a link between junk food and hormones. Comeau said that the unspecified "gender-bending chemicals" mentioned by the Daily Mail are likely a reference to phthalates.


Also known to as plasticizers, phthalates (pronounced "THA-lates") are used in the industrial production of shower curtains, medical bags and tubes, children's toys, and soap. Scientists suspect that these plasticizers sneak their way into the food supply via the industrial machinery used to make processed foods, as well as through the gloves used by factory workers.

Earlier this year, researchers found a direct link between consumption of fast food and phthalate levels in the urine of fast food consumers. But while phthalates have been linked to fertility problems and stunted penile development, research attempting to link them to gynecomastia has turned up short.

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Comeau also noted a recent study entitled "Phthalates impact human health: Epidemiological evidences and plausible mechanism of action" from the Journal of Hazardous Materials, which undertook an overview of past research "attempting to link the impact of phthalates with pubertal gynecomastia," though none was able to substantiate any such link.

As far as Comeau and a growing body of scientific inquiry are concerned, you don't have to worry about growing boobs if you're a guy who loves chicken tenders and cheeseburgers, aside from any that might come with the normal weight gain associated with eating a lot of fast food.

Dr. Peter Bray agrees. He's a Toronto-based plastic surgeon who performs breast reductions and treats breast asymmetry in his practice.


"Gynecomastia is a very common problem in teenage boys, as is breast asymmetry," Dr. Bray explains. "So the breast growth in this young man might have occurred with or without consumption of fast food. There is no specific medical test that would identify fast food as being the causal agent in any specific case."

Still, Bray says that there are some "legitimate reasons to suspect fast food might have a role in aggravating male breast enlargement."

Bray is skeptical as to the fast food hypothesis offered by Dr. Pan. "I doubt fast food is the sole explanation for the gynecomastia in this particular man. Any external cause, like fast food, would have an effect on both breasts to at least some degree, but there is no breast enlargement whatsoever on his left side."

Dr. Bray also touched on the issue of chemical additives like phthalates, and said it seemed possible that they might have "estrogen-like effects," but that's hardly enough to conclude that they could cause the growth of a single breast on a man.

Photo via Wikimedia Commons.

Still, Bray says that there are some "legitimate reasons to suspect fast food might have a role in aggravating male breast enlargement." Eating too much of it can contribute to a host of other health problems like obesity, which can also raise estrogen levels and increase breast size, though typically not asymmetrically.

"Weight gain can certainly manifest as increased breast size for male teens, as well as in other areas of their body, but it would not be classified as gynecomastia," Comeau concludes, citing a recent review of 26 studies looking at the relationship between processed foods and body fat during childhood and adolescence.

In other words, fast food might be giving you man boobs, but it's not because of any "gender-bending" chemicals; it's probably just because of your crappy diet.