van de Kamp ME, Seves SM, Temme EHM. Reducing GHG emissions while improving diet quality: exploring the potential of reduced meat, cheese and alcoholic and soft drinks consumption at specific moments during the day. BMC Public Health. 2018 Feb 20;18(1):264.
Using reported dietary intake data from a Dutch National Food Consumption Survey (2007–2010), the researchers created scenarios to recommend potential changes to reduce GHG emissions for survey respondents who had diets showing the highest GHG emissions. They also assessed the changes in nutrient content of reported dietary intakes in comparison to the dietary scenarios.
Bottom line for nutrition practice:
The results illustrate that for this group of respondents with high diet related GHG emissions, reducing red and processed meat intake (even if only at dinner time) and reducing soft and alcoholic drink consumption throughout the day would lead to reduced diet related GHG emissions. The single most effective change to reduce GHG emissions was reducing the consumption of meat. A 75% reduction in red and/or processed meat during dinner resulted in a 22 and 24% reduction in GHG emissions for women and men respectively. These changes would also benefit health by bringing consumption closer to the national dietary guidelines, and reduce saturated fat and sugar intake. As the changes also reduce iron intake, care must be taken to ensure adequate iron consumption, in particular for women of child-bearing age. Protein intake remained adequate in all scenarios.
The authors also note that these two changes (reducing meat and soft and alcoholic drink consumption) will save money, and are relatively easy changes to make (e.g., meat consumption is reduced, rather than replaced, because these respondents had on average a higher meat intake than recommended). They suggest that their study is novel, as dietary changes are based on the specific time period with the greatest potential GHG emission reductions. For example, as it is known that the majority of meat consumption occurs at dinner time, recommendations to decrease consumption focus specifically on this time period.
Background: The typical Western diet is associated with high levels of greenhouse gas (GHG) emissions and with obesity and other diet-related diseases. This study aims to determine the impact of adjustments to the current diet at specific moments of food consumption, to lower GHG emissions and improve diet quality.
Methods: Food consumption in the Netherlands was assessed by two non-consecutive 24-h recalls for adults aged 19-69 years (n = 2102). GHG emission of food consumption was evaluated with the use of life cycle assessments. The population was stratified by gender and according to tertiles of dietary GHG emission. Scenarios were developed to lower GHG emissions of people in the highest tertile of dietary GHG emission; 1) reducing red and processed meat consumed during dinner by 50% and 75%, 2) replacing 50% and 100% of alcoholic and soft drinks (including fruit and vegetable juice and mineral water) by tap water, 3) replacing cheese consumed in between meals by plant-based alternatives and 4) two combinations of these scenarios. Effects on GHG emission as well as nutrient content of the diet were assessed.
Results: The mean habitual daily dietary GHG emission in the highest tertile of dietary GHG emission was 6.7 kg CO2-equivalents for men and 5.1 kg CO2-equivalents for women. The scenarios with reduced meat consumption and/or replacement of all alcoholic and soft drinks were most successful in reducing dietary GHG emissions (ranging from – 15% to – 34%) and also reduced saturated fatty acid intake and/or sugar intake. Both types of scenarios lead to reduced energy and iron intakes. Protein intake remained adequate.
Conclusions: Reducing the consumption of red and processed meat during dinner and of soft and alcoholic drinks throughout the day leads to significantly lower dietary GHG emissions of people in the Netherlands in the highest tertile of dietary GHG emissions, while also having health benefits. For subgroups of the population not meeting energy or iron requirements as a result of these dietary changes, low GHG emission and nutritious replacement foods might be needed in order to meet energy and iron requirements.
Details of results:
Using reported dietary intake data from a Dutch National Food Consumption Survey (2007–2010), the researchers created scenarios to recommend potential changes to reduce GHG emissions for respondents who had diets showing the highest GHG emissions.
Meat, cheese, and drinks (alcoholic drinks and soft drinks including mineral water) were either reduced or replaced with healthier foods with lower GHG emissions for specific times of consumption during the day. This was done through a number of scenarios:
– All cheese eaten between meals was replaced by plant-based alternatives, such as unsalted nuts and cherry tomatoes (without bread) or peanut butter and vegetable sandwich spread (with bread) (referred to as ‘cheese’ scenario)
– Red and processed meat eaten at dinner, was reduced by 50% (referred to as ‘meat50’) or 75% (referred to as ‘meat75’)
– Soft drinks (including mineral water and fruit or vegetable juices) and alcoholic drinks were replaced by tap water by either 50% (referred to as ‘water50’) or 100% (referred to as ‘water100’) for all times of consumption. Coffee, coffee alternatives, tea, herbal tea and dairy drinks were not replaced.
– “Combi 50” included all reductions and replacements as defined in the ‘cheese’, ‘meat50’ and ‘water50’ scenarios
– “Combimax” included all reductions and replacements as defined in the ‘cheese’, ‘meat75’ and ‘water100’ scenarios
GHG emissions were significantly reduced in the ‘water100’, ‘meat50’, ‘meat75’, ‘combi50’ and ‘combimax’ scenarios. This ranged from less than 10% in the ‘water100”, to about 15% in the ‘meat50’, to up to 34% in the ‘combimax’ scenarios.
The most effective single change to reduce emissions for this group of respondents with high diet related GHG emissions was to reduce the consumption of meat. A 75% reduction in red and/or processed meat during dinner resulted in a 22 and 24% reduction in GHG emissions for women and men respectively. Women in this group went from a GHG emission of 5.1 to 4.0 (kg C02-eq) with the ‘meat 75’ shift. Men went from 6.7 to 5.1 (kg C02-eq).
Changing meat consumption – even if only at dinner time – in conjunction with reducing soft and alcoholic drink consumption throughout the day would lead to reduced diet related GHG emissions. It would also bring dietary intake closer in line with the national dietary guidelines, with the exception of ‘meat75’ and ‘combimax’ scenarios where meat consumption is slightly lower for women than recommended. Also, energy and iron intakes were low in some scenarios for a small group of people who already had low intakes. While the authors were unable to assess energy and iron adequacy, they stress that care must be taken to ensure women of childbearing age consume adequate iron. Changes in meat and drink consumption also reduced saturated fat and sugar intake, while protein intake remained adequate in all scenarios. The ‘combimax’ scenario also showed a significant 8–11% reduction in sodium intake. The authors further suggest that the reduction of drinks will have dental health benefits. Out of all drinks, soft drinks are an important contributor to GHG emissions for the whole population, whereas alcoholic drinks are an important contributor specific to adult men (whom have a higher alcohol intake than women).
As the scenarios were not tested on people, the authors note that a limitation is that they do not know if the reductions would be acceptable to their target group, or if reductions would be compensated for in other ways (e.g., if people would increase meat consumption at other times if reducing it at dinner). They also note that they did not look at a wide scope of environmental indicators, relying on GHG emission data only. Moreover, this study focussed on the food consumption of people in the highest tertile of GHG emission. This group had on average a higher meat and cheese intake than recommended. Even in the ‘combimax’ scenario, the remaining average daily meat consumption was 100 g for men and 60 g for women. Reducing meat consumption by 50 or 75% is not a suitable answer for all subgroups in a population, and most of the time care is needed to provide suitable substitutes that provide essential nutrients.
Finally, they suggest that additional research is needed to replicate the scenarios for people with lower dietary GHG emissions. They also note – similar to other authors – that research is required to determine how populations can be motivated to shift diets, emphasizing the need for interventions at societal and institutional levels rather than focusing on individuals.
Of additional interest:
For further information on how populations can shift diets, see also synopses of the following articles on this website:
Veltkamp M, Anschutz DJ, Kremers SP, Holland RW. Comparison of food recommendations varying in sustainability: Impact on dietary intake and motivation to follow recommendations. J Health Psychol. 2020 Mar;25(3):373-86.
Clark M, Macdiarmid J, Jones AD, Ranganathan J, Herrero M, Fanzo J. The Role of Healthy Diets in Environmentally Sustainable Food Systems. Food and Nutrition Bulletin. 2020;41(2_suppl):31S-58S.
While the authors note that the ‘cheese’ scenario (which replaced cheese with plant-based substitutes) did not significantly alter the intake of the selected nutrients, calcium was not one of the nutrients that they measured.
Open access link to article:
Conflict of interest/ Funding:
Funding for this research was provided by the Dutch Ministry of Economic Affairs, but the authors note that they had no role in the design, analysis, interpretation of data or writing of this article.
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