Richard Smith: Three myths blocking progress against NCD

richard_smith2The church at the House of St Barnabas was standing room only to hear Professor Robert Lustig, a paediatric endocrinologist from San Francisco, castigate our current attempts to counter the global pandemic of NCD. (I judge that we’ve reached the stage where NCD, like AIDS, no longer needs to be spelt out.)

Lustig, who has a YouTube video that has been viewed 4.9 million times and who has been interviewed by The BMJ, is clearly somebody who loves his high profile and his capacity to bewitch an audience. Although I’d heard a professor I admire dismiss him as “wholly wrong,” he didn’t encounter much dissent at the meeting organised by C3 Collaborating for Health. He spoke without notes and a PowerPoint presentation, the modern way.

Lustig built his talk around the three myths that he thinks are blocking progress on reducing the burden of NCD. For 30 years, he said, we’ve been concentrating on reducing total calories and fat but made little or no progress. Thinking has been based on bad science.

On the day he was speaking, the media were full of reports of the National Institute for Health and Care Excellence’s advice that people with a BMI of 30 or higher should be considered for bariatric surgery to reduce their chances of developing diabetes. Even diabetes advocates thought that this might be excessive and unaffordable. It certainly seems like an extreme example of starting at the wrong end of a problem.

Lustig’s first myth is that developing NCD is “a matter of calories in and calories out.” “Obesity is a red herring,” he said, despite being a former chair of the obesity task force of the Pediatric Endocrine Society. Globally, obesity and diabetes are certainly correlated, but they are not concordant. Obesity is increasing at 1% a year but diabetes at 4%, so diabetes cannot simply be a subset of obesity, as is often proposed. You can be thin (Lusting used the word to mean non-obese) and have NCD, or be obese and not have NCD. In the US, 20% of the population is obese and 80% of those people have NCD, but 40% of those with a normal body weight also have NCD. Such people are sometimes known as TOFIs, thin outside and fat inside. Overall, there are thus more “sick” thin people than obese people.

The second myth is that “a calorie is a calorie.” Lustig accused Coca-Cola of being one of the main proponents of this myth. If you eat almonds with a calorific value of 160, you actually absorb into the body only 130, said Lustig. The fibre in almonds means that fewer calories are absorbed. So with some foods, particularly those that are highly processed, all the calories that go through the mouth are absorbed, but with other (usually unprocessed) foods they are not. Then protein requires more energy than carbohydrates to absorb into the body. With fats, said Lusting, some—like omega-3 fatty acids—are essential for life, whereas others like transfats are the “devil incarnate.” (Lustig’s language regularly extended beyond the strictly scientific.)

But it’s sugar that really excites Lustig. Glucose is essential for life and our bodies manufacture it if we can’t take it in, but fructose (Lustig’s arch enemy) is not necessary for life, yet because it’s so sweet we love it. It is, says Lusting, “an energy source but not a nutrient.” He asked the audience if they could think of another example, and a man in the front row quickly answered “alcohol.” Lustig treats children with hereditary fructose intolerance, and if they survive their initial exposure to fructose they become “the healthiest people on the planet” through avoiding it completely. Lustig didn’t labour the point in this talk, but he and others think that the development of high fructose corn syrup has been a boon for the food industry because it’s cheap, much loved, and addictive, but a curse for the population as it’s a major cause of NCD.

Lustig made the general point that we need to know much more about how different foods are metabolised—nutritional biochemistry, as he called it.

Public health workers are very likely to support Lustig’s third myth that preventing NCD is a matter of personal responsibility. Four conditions, he argued, have to be met for something to be a matter of personal responsibility. Firstly, people have to have full knowledge, which is very much not the case for knowing what’s in processed foods (especially when there are 56 different names for sugars) and understanding the harms of potential foods. Secondly, people have to have access to good foods, which is not true in much of the world, including food deserts in high income countries. In many places, Coca-Cola is more available than water.

The third issue is affordability. Healthy eating is not affordable to many and society cannot afford to respond to the costs of NCD caused by unhealthy eating. Fourthly, matters cannot be a matter of personal responsibility when others are affected—as is undoubtedly the case with the high costs of NCD.

The main perpetrator of these myths is, for Lustig, the food industry. It has polluted our food supply over the past 40 years. He does, however, believe that the food industry has to be part of the solution, but that markets and voluntary agreements cannot solve the problem. Soda and sugar taxes and changes in subsidies are needed, but Lustig recognised that we know little about the effectiveness of these. Any tax would have to be big enough to hurt, and one danger is that soda is so profitable that the industry would absorb a tax rather pass it onto consumers.

One questioner brought the morning to an agreed conclusion when he observed that much of the science underpinning our knowledge of nutrition is weak, and that we create confusion, scepticism, and eventually nihilism for the public by not agreeing on whether total calories, fat, sugar, or whatever is the problem. Lustig agreed with both statements and observed that “if we all sing together it’s music, but if we sing separately it’s noise.” We are still some way from music.

Richard Smith was the editor of The BMJ until 2004. He is now chair of the board of trustees of icddr,b [formerly International Centre for Diarrhoeal Disease Research, Bangladesh], and chair of the board of Patients Know Best. He is also a trustee of C3 Collaborating for Health.

Competing interest: RS is an unpaid trustee of C3 Collaborating for Health.