National Obesity Forum report is flawed

The recent editorial titled ‘National Obesity Forum report is flawed’ was unfortunate. One might expect that the editorial following such a title would point out a fundamental problem with the report or argue that its main message was inappropriate. This editorial, however, did nothing of the sort. Instead, the criticism of the report was limited to a few particular details and to issues that were plainly outside the scope of the report.

The main message of the report is clear: avoid processed foods. The reason that the editorial did not criticize this message is, of course, because it is impossible to criticize. That is not simply because the message is too general to criticize, but rather because any objective assessment of the existing scientific evidence would arrive at the conclusion that more detailed population-level recommendations are unlikely to be helpful. Whether the goal is to stay lean (1) or to lose weight (2), the avoidance of processed foods is clearly critical, while dietary specifics beyond that appear to be largely irrelevant. Given the large and unpredictable inter-individual variability in the metabolic benefits of any particular diet and the fact that giving people freedom to choose their preferred foods makes it more likely that they will settle on a diet that they will actually stick with, the added complexity of a more specific message would not be justified.

Part of the problem seems to be that the editorial is focused on the short version of the report. By virtue of its structure with 10 bullet points, the short version of the report shifts the focus away from its main message and onto its specifics, which is a shame. The longer companion report by the same group titled ‘Healthy Eating Guidelines & Weight Loss Advice For The United Kingdom’, which is linked in the short report, does a much better job of continually reinforcing the idea that the important point is to avoid processed foods. Nevertheless, the main message in the short report is certainly clear enough.

But even in its attempts to criticize the specifics of the report, the editorial is off the mark. The editorial points out that the ‘systematic review … that the report quotes concluded that saturated fat was not associated with type 2 diabetes’ and, thus, recommendations about saturated fats are not relevant in the context of preventing type 2 diabetes. This statement appears to be meant as a criticism, but it is, in fact, exactly the point of the report: recommendations to avoid saturated fats are not well-motivated and, because they may lead people to replace saturated fats with processed foods that are known to be harmful, these recommendations should be disregarded. The editorial also claims that ‘the recommendations about limiting carbohydrates are too prescriptive’ and that ‘not all carbohydrates in the diet should be limited … foods rich in starch and fiber are beneficial for health.’ One can only assume that the author is referring to resistant starch, as the suggestion that the consumption of digestible starch should be further encouraged would be bewildering. But nowhere in the report does it suggest that people should cut back on resistant starch or fiber. Given that the main message of the report is to avoid processed foods, it is quite clearly in favor of increased resistant starch and fiber consumption.

The report is by no means perfect. In fact, there are number of specific points that could be legitimately criticized. For example, the suggestion to avoid snacking (which is endorsed by the editorial) is based on the unrealistic assumption that a dietary regime without snacks would be sustainable. Unfortunately, the realities of the modern world are such that most people who attempt to cut out snacks entirely will quickly fail and return to their old ways. Thus, an approach that recommended deliberate healthy snacking in order to render people more robust to the environmental cues that trigger the unplanned consumption of unhealthy snacks would be more useful. But neither this detail nor any other can justify a headline that calls the report flawed.

The fight against unhealthy eating is a fight against ignorance and disinformation. Scientists need to do their part by conveying a consistent, unified message that reflects the understanding that we have worked so hard to develop. Is there ambiguity and uncertainty in the science of healthy eating? Of course there is. And there is always going to be because the well-controlled experiments that would be necessary to clarify the effects of diet on long-term human health at a level of detail that is satisfying to scientists can never be done. But at the level of detail that matters to policy makers and the general public, all scientists are (or at least should be) in agreement that the key is to avoid processed foods, and that is the message that we should be promoting at every opportunity. All of the more specific recommendations that have scientific support – e.g. eat less added sugar, eat less salt, eat more fiber – follow directly from this one simple principle.

An editorial in the BMJ would have been a perfectly appropriate place to criticize the details of the report, but not before unequivocally supporting its main message. Perhaps the author of the editorial views the idea that processed foods should be avoided as so self-evident that it goes without saying, and therefore views it as safe to jump straight into arguments about the details. But that is certainly not what the headline calling the report flawed would suggest, and is certainly not how the negative comments about the report (from the editorial, as well as from other scientists and health professionals) have been interpreted in the media.

Whether we like it or not, the scientific discourse on healthy eating is closely watched, and we have a responsibility to conduct ourselves accordingly. When the message that reaches the general public is that, yet again, scientists cannot agree on healthy eating, we are doing serious damage. Fortunately, we do agree on the important points, so we simply need to make it a priority to frame the discourse within that context.

(1) Katz, D.L., and Meller, S. (2014). Can We Say What Diet Is Best for Health? Annual Review of Public Health 35, 83–103.

(2) Johnston, B.C., Kanters, S., Bandayrel, K., Wu, P., Naji, F., Siemieniuk, R.A., Ball, G.D.C., Busse, J.W., Thorlund, K., Guyatt, G., et al. (2014). Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults: A Meta-analysis. JAMA 312, 923.