Modelling techniques are revealing the improvements we can make to our nutrient intakes by switching to follow new dietary guidelines, and how we can perfect our individual diet with just a few extra tweaks.
Food based dietary guidelines (FBDG) – with a greater plant-based focus – have been developed by many countries to help us make the right food choices for maintaining good health and preventing chronic diseases.
The mathematical models can simulate the impact on our nutrition of following the FBDG. They can also model individual diets, and allow researchers to assess the effects of efforts to optimise diets by looking at alternative food choices.
‘Individual diet optimisation is a powerful tool for assessing the nutritional relevance of existing FBDGs and to test possible alternatives. – Maillot and Darmon, 2020’
The authors used this approach to look at whether the FBDGs introduced in France in 2017, which promote a more plant-based diet, would provide recommended levels of nutrients.
What’s changed in the 2017 French FBDGs?
Compared with the previous French FBDGs, the new 2017 FBDGs have introduced 4 main changes:
- They provide specific recommendations on pulses (eg, beans, peas, lentils) deli meats (eg, ham), nuts and wholegrain products
- They promote rapeseed, walnut and olive oils
- They distinguish between poultry and other meat
- They advise a reduction in the recommended consumption of dairy products from three to two servings daily
Optimising individual diets
The authors obtained details of over 1,800 peoples’ diets (observed diets) from a French survey conducted in 2006–2007. For each person, a new diet (DP2) was designed in line with the new FBDGs, with as few changes as possible from the person’s usual eating habits. Another diet (DP3) was also designed in line with the new FBDGs, but including three servings of dairy products daily instead of two.
Impact of FBDGs on nutritional value
The findings confirmed that the overall nutritional value of both the DP2 and DP3 diets was better than the observed diets.
Diets optimised with the DP2 model had a lower energy density and higher nutrient density than the observed diets. The DP2 diet also had reduced shortfalls in most vitamins and minerals that were inadequate in the observed diet.
However, in the DP3 model, the addition of an extra portion of dairy product every day was associated with significantly better intake of calcium than the DP2 and observed diets (51%, 58% and 16% of inadequacy in observed diets and in diets modelled with DP2 and DP3 respectively).
Dairy products are the only food group for which the recommended frequency for adults has been reduced from the previous guideline in France, the authors point out. However, dairy is by far the largest contributor to calcium intakes among French people, they said.
‘Applied to the French case, the results suggest that complying with current FBDGs, as interpreted in the models tested, would improve the overall nutritional quality of the diet of adults in France. However, the risk of inadequate calcium intakes would be increased’ – Maillot and Darmon, 2020.