Within the healthcare system, diet scores are used to assess whether a person has unhealthy eating habits. Such scores are also essential for researchers when assessing how the degree of adherence to a certain diet affects health. Reliable diet scores are important for researchers to draw the right conclusions from studies and for authorities to develop dietary recommendations that address sustainablity.
The EAT-Lancet diet emphasises a plant-based diet where whole grains, vegetables, fruits, and legumes comprise a greater proportion of foods consumed, and meat and dairy products are consumed in significantly smaller proportions. Previous research has shown that high adherence to this diet can prevent 54-63 percent of premature deaths and lower greenhouse gas emissions by 50 percent.
"Such findings can form the basis for future nutrition recommendations, but there is currently no consensus of how adherence to the EAT-Lancet diet should be evaluated, and this makes it difficult to follow up the effects of the diet," says Anna Stubbendorff, doctoral student in nutritional epidemiology at Lund University Diabetes Centre, who has led the study published in the journal The Lancet Planetary Health.
Sustainable nutrition guidelines
Since the EAT-Lancet commission published its recommendations in 2019, several diet scores that can be used to evaluate adherence have been constructed. The research team has examined how useful seven of these diet scores are, and found that two were particularly good at evaluating adherence to the diet.
"We need reliable diet scores in order to develop evidence-based nutrition recommendations that can help prevent disease and premature death. In this study, we have used the diet scores on three population studies to determine which scores are best at evaluating adherence to the EAT-Lancet diet. The study shows that the results differ greatly depending on which score we use," says Daniel Borch Ibsen, researcher in nutritional epidemiology at Steno Diabetes Center Aarhus, who led the study.
Two dietary scores performed best
The researchers have investigated how useful the diet scores are at assessing adherence to the diet in the population studies the Malmö Diet Cancer (MDC) in Sweden, a similar cohort in Denmark and a population study in Mexico. The two diet scores that performed best were the Stubbendorff score and the Colizzi score. These two scores grouped participants consistently when comparing high and low adherence to the EAT-Lancet reference diet. When the two scores were used to assess adherence, the researchers found a reduced risk of premature death in three cohorts, a reduced risk of stroke in two cohorts, and lower greenhouse emissions in MDC, which had access to such data. Since Anna Stubbendorff has developed the Stubbendorff score, she did not participate in the assessment of how useful her dietary score is.
"A desired feature of a diet score that assesses adherence to this diet is that individuals with a high intake of the recommended diet receive high scores, whereas individuals with a low intake receive low scores. The Stubbendorff score and the Colizzi score had this feature and were best at assessing adherence to the diet," says Daniel Borch Ibsen.
The EAT-Lancet diet is a science-based diet and research has shown health benefits with adherence to the diet.
"Our previous research has shown, for example, that people who had high adherence to the EAT-Lancet diet had a lower risk of developing type 2 diabetes. In our future studies, we also plan to investigate whether there may be disadvantages of the diet, as a result of possible deficiencies of vitamins and minerals," says Anna Stubbendorff, who is a dietitian.
