After being immersed in the nutrition community for so many decades, I’ve come to see a nearly insurmountable dilemma: nutrition can create more health than all the pills and procedures combined, but it remains so controversial and confusing that most people find it almost impossible to understand. In my opinion, this controversy and confusion need not exist. We must better understand the science of nutrition and, just as importantly, differentiate between reliable scientific evidence and the personal choices we make when presented with scientific evidence. These are too often confused.

In 1980, I wrote about decision-making and personal risk as they related to food believed to contain small amounts of toxic substances.^[1] This topic remains relevant today. I stress that we should be able to agree on the facts, as supported by science, while also accepting that each of us might choose to do something different with those facts. Our chosen actions are a personal matter, whether we arrive at them consciously or not.

Disagreements on using salt, oil, and sugar are good examples of how subjective choice can become conflated with objective science. However, before we get into the specifics of those debates, we should consider how we define nutrition.

Uncertainty in Nutrition

Many people obsess over using finite numbers to distinguish good from bad as if it is possible to quantify with absolute certainty what good nutrition is. However, unlike in engineering or physics, fields in which exacting numbers are desirable, exacting numbers are less important in biology. For nutrition, estimates of effects are generally more in order. Nevertheless, we do emphasize numbers and apparent precision in the general field of nutrition. For instance, we use numbers to describe the nutrient composition of food, give information on food labels, define upper and lower limits of clinical lab results, convey dose-response relationships, and create national dietary guidelines (e.g., minimum daily requirements, recommended daily nutrient allowances, upper safe levels).

To be clear, the use of these numbers is not inherently problematic. Fixed numbers can usefully represent statistical estimates of populations. However, in my experience, many people take this way of thinking too far, believing that those estimates apply equally to every individual in a population. (Similarly, many people inappropriately rely on statistical significance to lend the appearance of greater certainty; though statistical significance is certainly a useful tool, it is merely a benchmark on a continuum.)

To cut through the confusion that often accompanies a reductionist search for precision, I prefer a message that, although based on a vast body of supporting evidence, is simpler and can be distilled into two recommendations:

1. Consume whole foods, that is foods in a reasonably intact form, be they raw, cooked, diced, sliced, or combined with other foods. The important thing is that all of the nutrients in the food are consumed together rather than in isolation, as in supplements.
2. Avoid animal foods. Virtually all the nutrients essential for human health can be provided and even optimized by plant foods.

I estimate that at least 90 percent of optimal nutritional health can be achieved by following these two simple rules. (Learn more about the whole food, plant-based lifestyle; learn more about reductionism in nutrition.)

Fat, Sugar, Salt—and Choice

I know no reliable evidence that says you must avoid every drop of added oil at all costs. However, I choose to not use added oil for a few reasons: First, most of the marketplace oil is relatively rich in proinflammatory omega-6 fats that readily oxidize to free radicals and promote aging and the development of various degenerative diseases. Second, pure oil generally has very few nutrients, if any, but is very calorically dense. Thus, eating oil often results in eating fewer nutrient-rich whole foods. Third, added oil consumed in higher amounts is addictive. The more we eat it, the more we tend to want it.

These comments do not apply equally to whole foods like nuts, seeds, and avocados. Several studies show that heart disease risk decreases with the modest consumption of these foods. However, some individuals may discover they gain weight by overconsuming high-fat plant foods. This is where personal choice comes in.

As with added fats, there is no nutritional need for refined sugar, which can also be addictive in higher amounts, especially when used in beverages, pastries, and other processed foods. Consumption of these foods is associated with obesity, cardiovascular disease, dental caries, and diabetes. On the other hand, I am unaware of any scientifically verifiable evidence that suggests significant harm from adding small amounts of sugar or other sweeteners to what are otherwise whole food, plant-based recipes.

Lastly, similarly, salt can be addictive when used in higher amounts, especially when used in processed and animal-based foods. Overconsumption increases the risk of hypertension and cardiovascular disease, especially for those who appear genetically predisposed to these conditions. For these reasons, public health authorities have made efforts to reduce salt intake for many years.^[2] The World Health Organization recommends less than 5,000 milligrams of salt per day (2,000 milligrams of sodium per day); the UK, less than 3,000 milligrams of salt per day (1,200 milligrams sodium); and the US, less than 6,000 milligrams per day. To put those recommendations into perspective, consider that global per capita daily consumption is about 10,000 milligrams and that cardiovascular disease risk declines as salt intake decreases from 12,000 to 3,000 milligrams daily; I am not, however, aware of convincing evidence of lower disease risk below 3,000 milligrams.

Those who choose a whole food, plant-based lifestyle will avoid the large amounts of salt frequently found in animal-based and processed foods. In such cases, it is more than possible to maintain daily salt intake at or below around 1,500 milligrams, which is well within the safe range. What individuals choose to do with this information is, again, a matter of personal choice. Everyone must make their own risk assessment, but if one eats about 1,500 milligrams of salt daily, it would not be unreasonable for them to add some salt to the food they prepare at home. This might be especially important when introducing the diet to those less familiar with eating a whole food, plant-based diet. Finally, sodium consumption can also be affected by the degree to which one perspires; people who sweat a lot from exercise require more sodium and can even suffer serious health consequences from sodium deficiency.

Similarly, nuts can enhance taste, and sugar-rich maple syrup, dried fruits, and even small amounts of refined sugar can be used to encourage long-term adoption by those new to this diet without compromising health. But in doing so, one should strive to minimize their use, especially as people adapt to new taste preferences.

Applying This Information

How this information might be used in the kitchen is not in my wheelhouse—I only try to understand and share the science. I am confident in the science supporting this dietary lifestyle and enthusiastic about sharing the message with those who may be initially challenged by its tastes. Because most of us know the potential health benefits awaiting our new acquaintances and friends, I hope we can limit unnecessary arguments about details and instead emphasize the critical overall message that maximizes health for ourselves, others, and, indeed, for societal and planetary health.

References

1. Campbell, T. C. Chemical carcinogens and human risk assessment. Fed. Proc. 39, 2467-2484 (1980).
2. He, F. J. & MacGregor, G. A. Role of salt intake in prevention of cardiovascular disease: controversies and challenges. Nature Revs. Cardiology 15, 371-377 (2018).