Doctors, who prescribe drugs, are at the top of the health hierarchy, whereas nutritionists are near the bottom. At medical school students learn a huge amount about drugs, but little or nothing about food. When managing patients doctors think drugs first and any other response a long way second. We’ve had pharmacopeias for over a century, but we still await Paul Glasziou’s non-pharmaceutical pharmacopeia.

This is a familiar litany, but I was thinking about it as I was listening to Homero Martinez, a Mexican paediatrician, nutrition researcher, and friend, describe what can be called without exaggeration the nutrition catastrophe happening in Mexico. Tiago Villanueva has already given an excellent account of Homero’s talk, but, in essence, Mexico has moved rapidly from having many undernourished children to having one of the most overweight and obese populations in the world. Worse, stunting (indicating chronic undernutrition) and anaemia (shortage of iron) coexist within the same families and even the same individuals. This is the double burden of malnutrition.

In addition, around 70% of the population is “food insecure,” meaning that people do not have sufficient quantities of food available on a consistent basis, have insufficient resources for a healthy diet, or do not understand what makes a healthy diet or have access to clean food and water. The nutritional pattern is common in low and middle income countries.

At this point I must confess my passion for Mexico and its food. I have a son who lives in Mexico, and when asked what three things he loved most about Mexico he immediately answered, “the people, the food, and the weather.” In the summer we gorged on chilaquiles, chicken mole, fresh guacamole, caldo de calderon,  huevos divorciados, quesadillas, and the preHispanic foods of ants’ eggs, worms, and grasshoppers, all washed down with Mexican beer, tequila, and mescal. We even drove 50 miles to eat lamb tacos for breakfast with the full strength bottled Coca Cola that is both a curse and pleasure.

If you have the money and the knowledge you can eat as well in Mexico as in any country in the world. Most Mexicans, however, lack one, the other, or both, and I wonder if doctors help them. I fear not.

Doctors can help little with poverty, and I doubt that the average doctor could advise on how to eat a healthy diet on a low income. Even if they could they might think it beneath them or would say that they didn’t have the time.

Not all medical systems are so neglectful of diet. Ayurvedic and traditional Chinese medicine pay a lot of attention to diet, exercise, and how to live. The ancients, as always in my experience, knew something that we have forgotten.

Although there have been national nutrition surveys since 1988, the Mexican government has been slow to respond through a combination of inertia, “pitiless lobbying” by food and beverage companies, and corruption of politicians and professional societies. And the current response seems over medical and inadequate. One response is to drive universal health care, something which is admirable but will help little with an epidemic of obesity. A second response is to subsidise school lunches and foods like milk and maize. A third response is again through the health system, to diagnose and treat anaemia. The response to obesity is mainly to provide information, which again is an inadequate response.

The Mexican parliament is, however, about to debate the introduction of a soda tax. “Food taxes” are an understandable response to obesity, but unlike taxes on tobacco and alcohol they lack an evidence base—and because diet is so complex could have unintended consequences.

The response in any country, said Homero, has to be to involve multiple stakeholders, try many strategies, avoid the temptation of quick fixes, and recognise that efforts will have to be long term.

I can’t help think, however, that were it possible overnight to optimise the diet of Mexicans in exchange for closing all hospitals and expelling all doctors then that would be a good deal for the health of Mexicans. Such a deal is, of course, unthinkable, and food will continue to be neglected in favour of drugs and other medical interventions.

Competing interest: Homero Martinez works with the Central America centre, which is funded in part by the United Health Chronic Disease Initiative, which RS directs. The initiative also funds a centre in Northern Mexico that has a programme of community health workers working with communities and individuals to encourage healthy lifestyles, including healthier diets. In addition, RS is about two stone heavier than he should be and takes a polypill every night, so is guilty of hypocrisy, a capacity that separates humans from all other creatures. But he does love alcohol, including tequila and mescal.

Richard Smith was the editor of the BMJ until 2004 and is director of the United Health Group’s chronic disease initiative.