Plenty of vegetables, whole grains and legumes. Small amounts of red meat, poultry and fish. Eat a healthy, varied diet, preferably in the company of others. These are the dietary recommendations of the Planetary Health Diet, which has been developed with people and the environment in mind. The recommendations were made by the EAT Lancet Commission, led by Swedish climate scientist Johan Rockström, and the diet is also known as the EAT Lancet Diet.
But to what extent have the healthiest people in dietary surveys eaten according to this advice? This can be difficult to answer. There is currently no standardised index to measure this, so it’s like comparing apples and oranges.
Conflicting results
When researchers have looked at health outcomes related to dietary intake, the results have been contradictory, says PhD student Anna Stubbendorff. This makes it difficult to draw firm conclusions.
"There are so many different factors to consider, such as vegetables, legumes, fats and sugar consumption. A person's score for legume intake may be high in one index, but low in another. Because different dietary indices are used, the results vary," she says.
Anna Stubbendorff wants to change this. Using a scoring system, she has compared seven different dietary indices and how they measure adherence to the Planetary Health Diet. She then looked at the extent to which participants went on to suffer stroke and death.
She has created one of the indices herself, to find a measurement system that is easy to use and understand. Together with research colleagues, she has reviewed three large dietary studies:
- A dietary study in Malmö from the 1990s with about 21 000 participants
- A dietary study in Denmark from the 1990s with around 52 000 participants
- A dietary study with female teachers in Mexico from the 2000s with around 30 000 participants
Changing eating habits since the 1990s
The aim of her research was to find a common way of measuring, in order to gain a better understanding and ultimately contribute to improved dietary advice. The fact that two of the dietary studies examined were conducted in the 1990s was both positive and negative.
"As the participants have aged, we can measure both deaths and strokes. But one disadvantage is that we have changed our eating habits since the 1990s, we don't eat quite the same things as we did then. That's why it was good to include a more recent study that was also conducted in another part of the world, so that this is not just a Nordic study," she says.
Anna Stubbendorff's own dietary index scored well in the research and ranked highest, together with Colizzi's index. It should be emphasised that since Anna Stubbendorff developed the Stubbendorff index, she did not participate in the assessment of how useful her own dietary index is.
Anna now hopes that a measurement method can be agreed in the future.
"If we are to achieve the global goals of Agenda 2030, we need to change how we eat in the world. And then we need tools in the process of a more sustainable and healthy life and society, it also facilitates new policy instruments."
Not eating as recommended
Anna Stubbendorff is a dietitian and a member of the Faculty of medicine at Lund University. She is delighted, and perhaps unique, to have had her latest research article published in the Lancet Planetary Health. The 2030 Agenda Graduate School inspired her to take an interdisciplinary approach.
"This is the first time that this research group has published in Lancet Planetary Health."
So what about the participants in the dietary studies Anna looked at - were they eating according to current recommendations? No, not to a large extent. On the Stubbendorff index, eating exactly according to the EAT Lancet diet can score a maximum of 42 points. The average in the trials was just under 17 points. So we still have a long way to go.
"But if we can make the transition, millions of lives will be saved, there will be enough food for everyone and we will have less impact on the climate," she says.
Link to the article in The Lancet Planetary Health:
“A systematic evaluation of seven different scores representing the EAT–Lancet reference diet and mortality, stroke, and greenhouse gas emissions in three cohorts” - thelancet.com
Link to Anna Stubbendorff's personal page