This piece was originally published in 2021 in Morgenbladet; a Norwegian weekly newspaper covering politics, culture and science. Re-used here with permission on 23/11/2023.
Author: Marit Kolby (Bjørknes University College, Norway)
Douglas Adams’s cult classic “The Hitchhiker’s Guide to the Galaxy”, tells the story of hyper-intelligent panhuman beings who build a computer the size of a small planet to calculate the answer to “the ultimate question of life, the universe, and everything." After millions of years of processing, the computer stated: “I have an answer for you, but you won’t like it. The answer is 42”. This made no sense to the intelligent beings, and the computer explained: “I think the problem is that you simply haven’t understood the question”.
It is tempting to draw a parallel to the field of nutritional science. Intelligent scientists have used increasingly complex methods to try to answer our version of the ultimate question —what should we eat? Big Data generated from genomics, transcriptomics, proteomics and metabolomics is being fed into our version of the supercomputer: systems biology, in search of the ultimate answer. But the answers we get are contradictory, and among professionals the debate is loud and passionate. Who is right, if anyone?
Nutritionism
So how did we get here? From the very beginning of nutritional science, kicked off in the early 1900s by the discovery of vitamins, our scientific approach to food has been reductionist. This has given us vital knowledge about food, but we have also created the illusion that combinations of nutrients are all that matters. This approach to understanding food is known as nutritionism. In the world of nutritionism milk is calcium and fatty fish is omega-3, and based on the contents of nutrients we give advice on how to compose a healthy diet. However, this approach is insufficient for understanding how foods affect us.
Dietary advice provided by most health authorities evaluate foods based on calories, saturated fat, salt and fiber. Butter is thus theoretically unhealthy because of its saturated fat content. According to the same logic, fatty cheeses are supposed to be unhealthy, but in practice they turn out the opposite. Since obesity is the main driver of diet-related disease, the question of whether foods are fattening or slimming is at the center of the debate. In the wake of seemingly perpetual arguments about the contents of foods, people increasingly ignore governmental dietary advice. In the media, self-taught (and commercial) nutritionists are leading the way and will happily point out certain foods — such as fruits or honey — as either the source of or the solution to our health problems. Apparently, the confusion is complete.
You are what you eat
Everyone has opinions on food and nutrition because everyone eats and what we eat defines us. At the tables we find many different dietary ideologies represented. Some eat low-carb, while others go for a ketogenic diet — almost entirely without carbohydrates. Some are devoted vegans, some flexitarian, while others are swimming against the sustainable tide and have found new meaning through a “carnivore” diet — based solely on animal foods. In pursuit of the perfect diet, pleasure, culture and traditions end up giving way.
The degree of processing matters
Kevin Hall, senior investigator at the National Institute of Health, was fed up with the “diet wars” and designed a study with a novel approach in nutrition research. The study tested the effect of ultra-processed foods (industrially processed to such an extent that they have lost their health-preserving potential) against foods that are minimally processed. In the study, healthy volunteers were kept in closed research facilities for one month. For two weeks, the participants received either freshly prepared meals based on whole foods; an unprocessed diet, or industrial products made to be tasty, readily available, and ready to eat; an ultra-processed diet. After two weeks, they switched diets. Both diets were similar in terms of calories, fat, proteins, carbohydrates, salt and fiber, and the participants could eat as much as they wanted. So, what happened? When eating ultra-processed, the participants overconsumed without knowing it and they gained weight. When eating unprocessed, they lost weight without restricting their intake. The results from this study have given nutrition professionals around the world something new to think about. But was it really something new?
Traditional populations knew better
For most of the time man has existed on earth, the answer to the question of what to eat was this: Anything that’s available. Diets were determined by local geography and its flora and fauna. If you were born into the Inuit population in Greenland, the diet consisted of marine animals, land animals and birds. Most of the energy came from fat. If you happened to be born into the Tsimane population of Bolivia, rice, corn, root vegetables and fruits were on the menu, as well as sporadic meals of meat and fish. Most of the energy came from carbohydrates. Similar differences in dietary features were found between the Masaii in Kenya and Tanzania, and the population of the Kitava Islands in the Pacific. These traditional populations have had normal body weight and good health on diets that are sensationally different from the viewpoint of nutritional science. The common denominator is whole foods. Meals were freshly prepared, and surplus of foods were preserved with simple methods that keep the quality of the food intact.
Quality, not quantity, at the heart of nutritional assessment
Nutritional science has been searching for the right amounts of calories, fat, proteins, carbohydrates, salt and fiber, and answers have been conflicting. Did we simply misunderstand the question? The question of what to eat is not just about nutrients, but how to preserve the quality of whole foods. This is not achieved by changing the type of fat, subtracting salt or adding fiber to ultra-processed industrial products. Finally, nutritional research has provided an answer that makes sense and is in line with what we have practiced throughout most of our evolutionary history. But you might not like it. The answer is: freshly prepared meals from whole foods.
