Eating just one hot dog filled with meat could cost consumers 36 minutes of their healthy life, a new study published in the journal Nature Food has found. While eating a serving of nuts, instead, could help one gain 26 minutes of healthy life.
Conducted by the University of Michigan’s (UM) School of Public Health, the study has managed to identify environmentally sustainable foods that actively promote health. Researchers analysed nutritional profiles of certain types of food and made use of a new epidemiology-based nutritional index, the Health Nutritional Index (HENI), which the investigators developed in collaboration with nutritionist Victor Fulgoni III from Nutrition Impact LLC. The Index is an adaptation of the Global Burden of Disease (GBD) index, in which disease mortality and morbidity are associated with a single food choice of an individual. For HENI, researchers used 15 dietary risk factors and disease burden estimates from GBD and combined them with the nutrition profile of foods consumed in the United States, based on the ‘What We Eat in America’ database of the National Health and Nutrition Examination Survey. Accordingly, foods with positive scores add healthy minutes of life, while foods with negative scores are associated with health outcomes that can be detrimental for human health.
HENI allowed the researchers to quantify marginal health effects (in minutes of healthy life lost or gained) of more than 5,800 foods. They found that fruits, cooked grains, ready-to-eat cereals and non-starchy mixed vegetables resulted in the largest gains, while hot dogs, burgers, breakfast sandwiches and sugary drinks were linked to maximum reduction in lifespan.
Furthermore, to quantify a food’s impact on the environment, the researchers assessed water use and relied on IMPACT World+, a popular method of determining the environmental impact of a given food’s life cycle, from production to manufacturing, cooking, consumption and waste. They developed scores for 18 environmental indicators, taking into account detailed food recipes as well as anticipated food waste.
After analysing foods’ combined nutritional and environmental impacts, researchers categorised them into three different zones—green, yellow and red. Green zone foods (primarily legumes, whole grains, fruits, nuts and field-grown vegetables) are the most nutritionally beneficial, while having little adverse environmental impact. Foods in the red zone (beef, pork, lamb and processed meats) have negative effects on human as well as environmental health.
"Generally, dietary recommendations lack specific and actionable direction to motivate people to change their behaviour, and rarely do dietary recommendations address environmental impacts," said Dr Katerina Stylianou, lead researcher from the department of environmental health sciences at UM's School of Public Health.
Although the study found that plant-based foods generally performed better than animal-based foods, the researchers have warned against widely varying levels of environmental and health impacts in each of the two groups. For instance, while hot dogs resulted in 36 minutes of healthy life lost, chicken wings are associated with a loss of 3.3 minutes. Rice, beans and salted peanuts can add between 10 to 15 minutes of healthy life, while peanut butter and jelly sandwiches resulted in a gain of 33 minutes.
"Previous studies have often reduced their findings to a plant vs. animal-based foods discussion. Although we find that plant-based foods generally perform better, there are considerable variations within both plant-based and animal-based foods,” explained Dr Stylianou.
Based on their findings, researchers suggest decreasing foods with the most negative health and environmental impacts including high processed meat, beef and shrimp, followed by pork, lamb and greenhouse-grown vegetables. Additionally, increasing the most nutritionally beneficial foods, including field-grown fruits and vegetables, legumes, nuts and low-environmental impact seafood, will improve the possibility of leading a healthier and longer life.
"The urgency of dietary changes to improve human health and the environment is clear. Our findings demonstrate that small targeted substitutions offer a feasible and powerful strategy to achieve significant health and environmental benefits without requiring dramatic dietary shifts,” said Prof Olivier Jolliet, co-author of the study.