Modeling a sustainable plant-based healthy diet for a dietary transition in the United States

By Neha MathurNov 30 2023Reviewed by Lily Ramsey, LLM

In a recent study published in the Npj Vaccines Journal, researchers presented intriguing perspectives about sustainable dietary modeling and formulation in the animal-to-plant-based dietary (PBD) transition.

Study: Sustainable healthy diet modeling for a plant-based dietary transitioning in the United States. Image Credit: RONEDYA/Shutterstock.com

Background

There are several different definitions of PBDs based on social, cultural, and agricultural influences across geographical regions.

In this study, authors followed the PBD definition outlined by the World Health Organization (WHO), which includes fruits, vegetables, grains, legumes, nuts, and seeds in unprocessed or minimally processed forms in PBDs.

There are several benefits of PBDs, such as reducing adverse environmental impacts and lowering the risks of noncommunicable chronic diseases (NCDs), e.g., cancer and type 2 diabetes. PBDs are gaining popularity due to their benefits on human health and the environment. 

About the study

In the present study, researchers developed three dietary models labeled M1, M2, and M3 containing 24 composite diet scenarios (S) using the Food4HealthyLife calculator tool, where M1 targeted the replacement of red meat, M2 targeted the replacement of red and white meat, and M3 targeted the replacement of red, white, and processed meat.

They used the Health Nutritional Index (HENI) and Food Compass scoring (FCS) systems for nutritional quality profiling of all diets assessed and the midpoint impact values for foods listed in the What We Eat in America database to derive estimates of the 18 environmental impact indicators, including global warming, water use, and mineral resources.

Specifically, they adopted 46 attributes and seven domains of the slightly modified FCS method and treated red meats and processed meats as separate attributes.

The final Food Compass Score was the sum of the average domain score and the sum of scores for the food ingredients domain. The HENI tool assessed the health impact of diets using disability-adjusted life years (DALYs).

In model diets provided by the Food4HealthyLife calculator, the "current diet" was the default diet that people adopted but negatively impacted life expectancy, whereas the "optimal diet" referred to a hypothetical dietary pattern that increased life expectancy but was not feasible in real life, and the "feasible diet" was a midpoint between these two diets.

In addition, the researchers created seven additional diet scenarios using arithmetic mathematical equations developed by the authors, resulting in ten hypothetical diet scenarios for each diet consumption model.

The authors used these equations to calculate the appropriate weights of the targeted food groups in each alternative diet scenario, ensuring a partial replacement of meat with legumes in each scenario.

These diet consumption models included 14 different food groups, each represented by a specific type of food chosen based on its availability and popularity. 

They used the USDA Food Availability and Consumption Database as a reference to determine the most commonly consumed foods. This database has been tracking trends in food consumption in the US for a long time and informs policy decisions related to nutrition and public health.

The total weight of each diet scenario was 1.8 kg. However, notably, none of the modeling scenarios of the study impacted the cooking and storage losses.

Assessment of the nutritional quality of different model diets involved determining the nutritional contents per 100 calories of the model diets using an online diet analysis system called FoodStruct, and the second step involved using a scoring system called Food Compass Scoring to rate each model diet.

Further, the researchers used the Diet Analysis menu of the FoodStruct to analyze quantities of ingredients in each diet scenario, including macronutrients (carbohydrates, proteins, lipids, and fiber) and micronutrients (nine minerals and 12 vitamins).

They also estimated the contents of specific lipids, such as cholesterol, eicosapentaenoic acid (EPA), alpha-linolenic acid, and docosahexaenoic acid (DHA).

Furthermore, the team conducted nutritional-environmental trade-off analyses using dual-scale data charts and HENI and Food Compass scores, global warming, ionizing radiation, and freshwater eutrophication to identify the optimal composite diet scenario. 

Finally, the researchers conducted a Pearson correlation analysis to assess the correlation between calories, nutritional quality indicators, and environmental impact indicators of diet scenarios. 

They ranked the diets using the Kruskal‒Wallis nonparametric test, which used the HENI scores, FCS, and total human health damage. 

Results

First, the results showed that as the percentage of meat products substituted with plant-based foods increased in the model composite diets, a non-linear variation in nutritional, environmental, and health benefits emerged, implying varying impact of specific variables.

Six of the seven domains used in the Food Compass nutrient profiling contributed to the obtained FCS scores. On average, specific lipids contributed the least, and vitamins contributed the most (0.051% and 31.41%).

Other domains that made significant contributions were the nutrient ratio, minerals, food ingredients, protein, and fiber, with donations of 27.36%, 10.99%, 23.19%, and 6.99%, respectively.

The study compared different diet scenarios and found that the recommended regular composite diet should consist of 10% legumes, 0.11% red meat, 2.81% white meat, and 0.28% processed meat. It was estimated to offset about 55% of global warming impacts.

Additionally, it was associated with a diet quality score of 74.13 on the FCS system, indicating that this diet was relatively healthy and balanced.

Furthermore, the recommended composite diet potentially redeemed about 169.21 minutes of DALY.

Conclusions

The study data presents an interesting forecast of the benefits of transitioning to an optimal and sustainable plant- and animal-based dietary pattern.

This type of dietary transition requires a more comprehensive approach that includes modeling the substitution of animal-based foods with plant-based alternatives, such that it minimizes environmental impact while maximizing nutritional and health benefits. 

In this dietary shift, simply increasing the proportion of plant-based foods may not necessarily reduce environmental and health damage caused by the current food systems. Other factors, such as the quantity, type, characteristics, and food sources, need consideration.

Importantly, if not properly tracked and optimized, a supposed sustainable shift towards a plant-based diet may inadvertently lead to negative consequences.