Data available in the country regarding the EFPs of Lebanese adults’ dietary patterns belong to the pattern of the year 2009 [7]. Although important, it was crucial to assess the EFPs of the current dietary patterns due to the shift that occurred because of the many factors (COVID-19, the Beirut blast, and the economic crisis) that affected the country since then. This study presents updated data on this topic, which is valuable in a country struggling economically and environmentally. Compared to the previous data, the overall GHGE slightly increased from 4.06 kg CO2−eq/d to 4.43 kg CO2−eq/d, and the overall water footprint increased from 2,571.62 L/d to 2,862.39 L/d. To allow a better comparison, EFPs in 1000 kcal were used. The previous EFPs (year 2009) reported in 1000 kcal were 1.53 kg CO2−eq/1000 kcal and 951.68 L/1000 kcal for GHGE and water footprint, respectively [7]. Based on the current dietary patterns, the GHGE increased to 2.2 kg CO2−eq/1000 kcal, and the water footprint increased to 1,436.73 L/1000 kcal. This can be explained by the increased consumption of fruits, dairy products, chips, salty crackers, sweets, added sugars, and hot beverages compared to the year 2009, faced by a decrease in the consumption of sugar-sweetened beverages and alcohol only. To compare our findings with other countries, EFPs in 2500 kcal/d were calculated and were as follows: Mean ± SD: GHGE: 5.5 ± 3.93 kg CO2−eq; water footprint: 3,591.83 ± 2,164.88 L/d; nitrogen content: 15.98 ± 9.82 g.

For water use, the average use per person was higher than the global average (2,799 L/d) [22]. Higher estimates were obtained in North America (3,999 L/d) [23], while lower estimates were obtained in Tunisia (3,292 L/d) [24] and Finland (2,377 L/d) [23]. Almost similar estimates were obtained in Italy (3,469 L/d) [23]. In our study, grains and cereals (21.13%) were the most contributing to the water footprint, followed by meat (18.25%). In Italy [23], cereals and bakery products were the most contributors to the total water footprint, which aligns with our findings. In Tunisia [24], meat was the main contributor to the water footprint, followed by cereals, which are the two most contributing groups in our study. The findings of our study showed that the current consumption’s water footprint exceeded the global average, which is alarming in a country facing many environmental problems such as air pollution, waste accumulation, and water shortages [9]. For instance, Lebanon’s renewable water resources are currently less than 1000m3/capita/year (2740 L/d), which is the threshold that defines “water stress” [9].

For GHGEs associated with the current dietary pattern in Lebanon, an average of 5.5 kg CO2−eq is emitted per day. Higher estimates were obtained in the United Kingdom (7.4 kg CO2−eq/d) and Australia (19.5 kg CO2−eq/d) [25, 26], while lower estimates are found in the United States (3.55 kg CO2−eq/d) [27] and France (4.8 kg CO2−eq/d) [28]. Animal products were the main contributors to GHGEs in our study. Meat was the most contributor to the GHGEs, followed by the ‘grains and cereals’ group. Meat and meat alternatives contributed to the highest GHGEs in Australia (33.9%) and the UK (32%) [25, 26], which aligns with our findings (26.45%). Meat and meat alternatives were also the main contributors to GHGEs in France [28]. The current findings are considered alarming, as a previous report stated that GHGEs in the country increased by 129% between 1994 and 2015 [9].

In addition to the GHGEs and water footprint, this study is the first in Lebanon and the Arab Region to assess the nitrogen content of food consumed, which is eventually lost to the environment. Assessing nitrogen lost to the environment is crucial because nitrogen is the most prolific gas in the atmosphere [29]. For instance, nitrogen lost to the environment can cause pollution that harms the environment in many ways. Based on the UNEP, nitrous oxide (N2O) is way more powerful than carbon dioxide (CO2) and methane (CH4) as a greenhouse gas and is believed to be the greatest human-made threat to the ozone layer [29]. In Ukraine [30], the consumption of plant-based food led to a higher nitrogen footprint (2.35 kg/year) compared to animal food (1.79 kg/year), which aligns with our findings (2.26 kg/year and 2.16 kg/year for plant-based food and animal-based food, respectively). Overall, the contribution of these two groups to the nitrogen footprint was 4.14 kg/year in Ukraine and 4.42 kg/year in our study, which is almost similar. In addition, cereals were the main contributors to the plant-based nitrogen footprint, similarly to our findings [30]. Contrasting our findings, milk was the main contributor from the animal products in Ukraine [30], while meat was the main contributor in our study.

Compared to environmental constraints based on data from 152 countries [31], the water footprint in our study sample represents 364% of the limit (786 L/cap/day), GHGEs represent 237% of the limit (1,866 g CO2-eq/cap/day), and the amount of nitrogen lost to the environment represents 46% of the limit set (27.4 g Nitrogen/cap/day). It is important to note that the nitrogen footprint in our study represents only consumption, which is alarming as it alone exceeded 45% of the limit.

The current findings, along with the findings of the recent study that assessed the nutritional value of the dietary pattern of Lebanese adults [8], show that this pattern is lacking essential vitamins and minerals and high in EFPs. Shifting towards healthier and more sustainable diets is therefore crucial to improve both the health of the population and the environmental assets. Such a positive shift can be following the Barilla Center for Food & Nutrition Double Pyramid (Food-Environmental Pyramid) [5], which shows that food that are recommended to be consumed in higher proportions have lower environmental footprints. Cheese in this double pyramid is separated from other dairy products as it has higher EFPs compared to milk and yogurt. Based on the Double Pyramid, fruits have the lowest EFPs, followed by vegetables and cereals, and thus these groups are recommended to be consumed in higher amounts. For better health benefits, grains and cereals are preferred to be whole grains, which is not the case in our study. As can be seen in Fig. 3, the deviation from the Double Pyramid in our sample occurred with sweets and red meat being the 3rd most consumed food items (instead of being the least) and olive oil the least consumed item (instead of being the 3rd ). As such, a decrease in the consumption of sweets and red meat in our sample and an increase in the consumption of olive oil would benefit both the health of our population and the environment. For instance, red meat and sweets have high EFPs and are low in essential vitamins and minerals and are linked to many chronic diseases, while olive oil has lower EFPs and is healthier as it offers many health benefits by being high in monounsaturated fatty acids, which are healthy fats that lower the risk of cardiovascular diseases and inflammation [32]. Overall, the consumption of more plant-based food and lowering the consumption of animal-based food is recommended as it would benefit both people and the environment. Besides the Double Pyramid, the Mediterranean Diet (MD) has been acknowledged as a sustainable diet due to its potential ability to mitigate climate change and its reduced environmental impact on water, soil, and energy use [33]. Encouraging MD adherence might thus serve as an efficient approach to improve our population’s overall health while protecting the country’s environmental assets, as a low adherence to this diet in this population was revealed in a recent study [8].

In our population, there is an obvious reliance on ‘grains and cereals’ as the main contributors to energy intake, and this group contributed significantly to the EFPs in our study. Thus, in addition to encouraging the consumption of whole grains, balancing the EFPs of these items is crucial. This can be done by optimizing irrigation systems in the country, as irrigation management practices significantly influence GHGEs, economic crop water productivity, and soil water content [34].

When it comes to safeguarding the environment, government initiatives like fuel standards upgrades, carbon fees, and laws prohibiting the destruction of old-growth forests have significantly lessened environmental effects than any one person, family, or community could on their own [35]. It is evidenced that a plant-based diet, fewer clothes, and less air travel would only cut greenhouse gas emissions by 25% of what is required to prevent global warming to 1.5 °C over pre-industrial levels, even if everyone on the earth adopted these changes. For instance, many people do not think it is credible to make further “lifestyle” adjustments because they already believe they are doing more to safeguard the environment than governments [35], highlighting the need for effective and efficient policies and public health policies to safeguard the environment and encourage the adoption of more sustainable choices.

This study assessed the EFPs of the current dietary pattern followed by Lebanese adults. The sample of this study is representative, so the findings, which are valuable as being the most updated findings on this topic in the country, can be generalized for the overall population. In addition, this is the first study in the Arab Region to assess the nitrogen lost to the environment due to consumption, which presents unique and crucial data on a topic that is gaining more attention recently. However, this study has some limitations:, it is important to acknowledge that selecting only one participant per household may have introduced bias by not accounting for within-household heterogeneity. Specific criteria were applied for participant selection, including willingness to participate, availability, and capacity to provide accurate information about dietary habits and household characteristics. Randomization within households was not feasible due to logistical constraints and the voluntary nature of the study. While this approach ensured broad coverage of households and minimized clustering effects, it may limit the exploration of individual differences within larger households. Despite this limitation, the use of stratified cluster sampling and recruitment from diverse channels aimed to capture heterogeneity across households at the community level, enhancing the external validity and generalizability of the findings. In addition, the method used for dietary assessment relies on recalling and is thus subject to inaccuracies (estimating portion sizes or remembering), although facilitating tools were offered to participants to decrease this as much as possible. Moreover, data on nitrogen from production, energy use, and other factors that are taken into consideration when calculating the nitrogen footprint in a country are lacking in Lebanon, so the nitrogen in our study represents one aspect of the footprint that is consumption.