Some Mexicans with family ties or dual citizenship in the U.S., or who can afford the airfare, head north of the border to get vaccinated faster than the months of waiting for one back home.

U.S. tourists aren't welcome in most countries because of the surging coronavirus. But Mexico lets them in, with no quarantine or test requirements.

"The damage of this kind of diet is even more visible because of the pandemic," says a Oaxaca legislator who spearheaded a law against the sale of junk food and soda to minors. The idea is spreading.

Low earners have been doubly hit: They make up the highest share of virus-related deaths and lack the funds to stay afloat as the pandemic plunges Mexico deeper into recession.