Nutrition Notes

A Closer Look at Recent Research on Highly Processed Foods

A study published recently in the journal Nutrients sounded the alarm about salt, sugar, saturated fat and total calories in highly processed packaged foods—the kinds that currently dominate the US food supply. The study, “The Healthfulness of the US Packaged Food and Beverage Supply: A Cross-Sectional Study,” comes from Northwestern University and was intended “to provide new information for consumers, researchers and policymakers to encourage food manufacturers to reformulate or replace unhealthy products and to inform the U.S. government on where action may be needed to improve the healthfulness of the U.S. packaged food and beverage supply.” A noble cause, certainly, but one not without its flaws. Let’s take a closer look at the weaknesses of such an assessment.

Food products evaluated in this study were ranked based on criteria that place greater emphasis on dietary aspects that the public are generally advised to avoid—such as saturated fat, sodium and sugar—and less emphasis on the nutrient density of an item—the vitamins, minerals and essential amino acids. One of the criteria employed—the Health Star Rating (HSR) system used in Australia and New Zealand—is highly flawed and misleading. It makes no distinction between naturally occurring and added sugars, which results in sugary breakfast cereals being anointed with a high score, and highly nutritious foods that may be high in fat and low in fiber (Greek yogurt, for example) receiving lower scores. Numerous media outlets have called for changes to the HSR system for this reason and others—including that HSR scores are intended to allow comparison only among similar products rather than between product categories. In other words, the rating for a packaged pastry is compared against parameters for other pastries, not against, say, sardines, or some other much more nutritious food.

Another problematic aspect of this study is that it is, at least in part, based on outdated science. Lead author Abigail Baldridge said, “To say that our food supply is highly processed won't shock anyone, but it's important that we hold food and beverage manufacturers accountable by continually documenting how they're doing in terms of providing healthy foods for consumers. And the verdict is they can and should be doing a whole lot better.” No one would argue that reading ingredient lists and Nutrition Facts panels on ultra-processed food products should come with warnings about being horrified and going into shock, but the reasons for these reactions may be different from what one would first assume.

Saying that food manufacturers “can and should be doing a whole lot better” implies that what they’re doing now is wrong. Some of it is, yes, but not all of it. For example, sodium is fingered as a negative aspect of ultra-processed foods, but a large and still expanding body of research indicates that decades of warnings about the dangers of high-sodium diets and advice to consume a low-sodium diet are not supported by the data. Low sodium intake is more strongly correlated with risk for cardiovascular (CV) events than higher intakes are. The sweet spot—the lowest risk for such events—was seen at approximately 5 grams of sodium per day, which is above the 2300 mg daily limit currently recommended by the American Heart Association and well above the 1500 mg limit the organization says is “ideal.” Based on data from over 82,000 subjects, the lowest tertile of sodium intake had a significant inverse relationship with CV events, while the highest tertile had a positive but non-significant correlation. Continued fearmongering about sodium is misleading to the public. With a tsunami of cardiometabolic disease crashing down upon us, people deserve better.

Another dietary element studies looking at processed foods might be misrepresenting is saturated fat. Like sodium—but perhaps even more so—saturated fat has for decades stood accused of crimes against human health. However, this delicious nutrient, found in healthy and/or nutrient-rich foods such as red meat, full-fat dairy, and coconut, has finally been exonerated after meta-analyses too numerous to ignore concluded that there’s no association between saturated fat intake and risk for cardiovascular or coronary heart disease.

While saturated fat continues to be wrongfully demonized, polyunsaturated fats are lauded as health-promoting. This, too, misleads the public. The only truly biologically “essential” fatty acids belong to the polyunsaturated category (n-3 alpha-linolenic acid and n-6 linoleic acid), but never before in human history did we consume n-6 fats in the quantities we do today, thanks only to extraction and processing technology that wrenches oil out of soybeans, corn kernels, cottonseeds and safflower seeds. The high level of n-6 in the modern diet, particularly when coupled with a high refined sugar intake, appears to be far more harmful for cardiovascular health than saturated fat ever was.

Cooking at home from whole, unprocessed items—foods that either don’t come with a barcode or that are one-ingredient foods (beef, salmon, turkey, avocado, broccoli, carrots, onions) is a way to ensure avoidance of excessive amounts of sugar, refined grains and polyunsaturated seed oils. But in the modern world, many people are lucky if they have the time, the resources, and the knowledge to do most of their cooking from scratch at home. Processed foods are convenient and often economical. Patients (and their doctors!) need not fear these entirely. These can, in fact, fit into a healthy and nutritious diet. People just need to understand how to read labels and ingredient lists to be aware of what, exactly, the products contain, and whether or not any individual ingredient is reason for concern.