3.1. “Whole Diet” Study
The results obtained for the three food patterns (whole diet study), according to each method of analysis (indicator), are reported in
Table 1.
The analysis results are expressed in points for week (Pt/week): the higher the “score” in Pt, the higher the damage to the environment.
Table 1.
Whole diet study: total and partial environmental impacts (indicated as single score, Pt per week) of the three complete food patterns, according to each indicator.
Table 1.
Whole diet study: total and partial environmental impacts (indicated as single score, Pt per week) of the three complete food patterns, according to each indicator.
Pattern/kcal | VEG 1600 | VEG 2400 | VEG 3200 | LOV 1600 | LOV 2400 | LOV 3200 | OMN 1600 | OMN 2400 | OMN 3200 |
---|
Ecoindicator99 |
Total | 0.64800481 | 0.94997163 | 1.3071604 | 2.3859409 | 2.6923735 | 3.0492296 | 3.7122608 | 4.40574 | 4.9341334 |
Carcinogens | 0.00019843 | 0.000286384 | 0.00036383 | 0.00133281 | 0.00142583 | 0.00150253 | 0.001630978 | 0.00180755 | 0.001925124 |
Respiratory organics | 0.00018305 | 0.000251572 | 0.0003258 | 0.00030875 | 0.00037811 | 0.00045206 | 0.000417358 | 0.000518085 | 0.000606523 |
Respiratory inorganics | 0.10049695 | 0.14412463 | 0.18855662 | 0.17767523 | 0.22237083 | 0.26670832 | 0.28722378 | 0.36469605 | 0.42409415 |
Climate change | 0.03919139 | 0.055214859 | 0.0709742 | 0.13229725 | 0.14852923 | 0.16416739 | 0.17863998 | 0.20869219 | 0.23059325 |
Radiation | 0.00002247 | 3.42 × 10−5 | 4.34 × 10−5 | 0.00038047 | 0.00039248 | 0.00040169 | 0.000398937 | 0.000416055 | 0.000427788 |
Ozone layer | 0.00001066 | 1.47 × 10−5 | 1.90 × 10−5 | 3.40 × 10−5 | 3.85 × 10−5 | 4.27 × 10−5 | 5.57 × 10−5 | 6.64 × 10−5 | 7.36 × 10−5 |
Ecotoxicity | 0.00106054 | 0.001434384 | 0.00171095 | 0.0026162 | 0.00302211 | 0.00329787 | 0.003002629 | 0.003519975 | 0.003860926 |
Acidification/Eutrophication | 0.02526500 | 0.036874031 | 0.04925412 | 0.04261296 | 0.05475953 | 0.0671279 | 0.090794324 | 0.11735622 | 0.13629427 |
Land and water use | 0.29042511 | 0.43349405 | 0.63636379 | 1.0764882 | 1.2228196 | 1.4256888 | 2.117066 | 2.5657137 | 2.9009677 |
Minerals | 0.00006435 | 9.65× 10−5 | 0.00012433 | 0.00053008 | 0.00056272 | 0.00059049 | 0.000579085 | 0.00062538 | 0.000659985 |
Fossil fuels | 0.19108686 | 0.27814636 | 0.35942432 | 0.95166495 | 1.0380746 | 1.1192498 | 1.0324519 | 1.1423284 | 1.2346302 |
Ecopoint |
Total | 6962.153 | 9977.3835 | 13418.176 | 13599.654 | 16700.341 | 20134.632 | 26697.481 | 33726.743 | 38929.907 |
NOx | 1190.3383 | 1687.0413 | 2174.7931 | 2741.075 | 3239.3288 | 3725.3904 | 3351.1462 | 4029.0262 | 4599.7719 |
SOx | 769.90348 | 1087.0439 | 1383.1478 | 1016.3942 | 1333.0982 | 1628.8733 | 1078.1917 | 1416.3569 | 1723.7377 |
NMVOC | 139.32288 | 192.98861 | 253.43336 | 273.88218 | 328.37026 | 388.55252 | 350.76288 | 427.2963 | 497.94655 |
NH3 | 842.99251 | 1250.5947 | 1703.2695 | 1192.126 | 1627.3129 | 2079.9873 | 3490.5891 | 4614.2057 | 5379.5064 |
Dust PM10 | 9.0847823 | 12.923818 | 15.191499 | 65.534052 | 69.802741 | 72.053644 | 72.707679 | 79.03103 | 82.418179 |
CO2 | 1377.9895 | 1943.5007 | 2498.664 | 4725.9375 | 5298.3987 | 5849.4224 | 6340.5217 | 7394.1754 | 8163.2418 |
Ozone layer | 0.6610465 | 0.90966159 | 1.1767778 | 2.1511266 | 2.4272521 | 2.689679 | 3.4930708 | 4.1519191 | 4.5977102 |
Pb (air) | 0.32147787 | 0.47727671 | 0.60871325 | 1.5374657 | 1.702998 | 1.833917 | 2.0107655 | 2.3081678 | 2.5067236 |
Cd (air) | 1.5009171 | 2.1788895 | 2.7819723 | 9.748633 | 10.451046 | 11.049965 | 11.405062 | 12.571727 | 13.398671 |
Zn (air) | 0.34491482 | 0.51571004 | 0.66441941 | 1.0479235 | 1.2308866 | 1.3790125 | 1.6420776 | 1.9914576 | 2.2250812 |
Hg (air) | 1.1709015 | 1.7566871 | 2.2428252 | 11.655909 | 12.243954 | 12.729547 | 12.321511 | 13.092723 | 13.669511 |
COD | 4.5777467 | 6.6868027 | 8.6133306 | 25.25851 | 27.433316 | 29.349171 | 30.326905 | 33.929372 | 36.545081 |
P | 466.47307 | 688.61262 | 932.40825 | 605.62586 | 831.28441 | 1075.0789 | 1216.5565 | 1613.6763 | 1938.9971 |
N | 2080.5034 | 2992.2043 | 4299.9698 | 2621.3589 | 3578.1404 | 4885.9003 | 10,403.361 | 13,712.094 | 16,063.676 |
Cr (water) | 0.18439044 | 0.27280425 | 0.34372097 | 1.9087695 | 2.0000171 | 2.0706068 | 2.1334244 | 2.2856304 | 2.3864404 |
Zn (water) | 0.11026105 | 0.16221025 | 0.20594354 | 0.94313822 | 0.99673879 | 1.0402484 | 1.0679982 | 1.1560351 | 1.2165352 |
Cu (water) | 0.15052732 | 0.22462302 | 0.28297967 | 1.7211955 | 1.7973628 | 1.855504 | 1.9056096 | 2.0314536 | 2.1143221 |
Cd (water) | 0.18614116 | 0.27169122 | 0.35127599 | 0.55325881 | 0.64589623 | 0.72481966 | 0.91269133 | 1.1064944 | 1.2360639 |
Hg (water) | 0.7057345 | 1.0552604 | 1.3499184 | 5.9398762 | 6.286672 | 6.5811908 | 6.2440261 | 6.6747297 | 7.0105413 |
Pb (water) | 0.0305093 | 0.045206483 | 0.05642818 | 0.30565965 | 0.32090765 | 0.33209206 | 0.33619951 | 0.35977884 | 0.37519415 |
Ni (water) | 0.02068235 | 0.030679134 | 0.03847235 | 0.23622184 | 0.24660089 | 0.25435586 | 0.26447911 | 0.28248352 | 0.29403315 |
AOX (water) | 0.00530489 | 0.007279036 | 0.00937398 | 0.01604704 | 0.01823847 | 0.02029386 | 0.027071622 | 0.032408888 | 0.03596629 |
Metals (soil) | 0.21573554 | 0.31068211 | 0.39921194 | 1.1959458 | 1.2942133 | 1.382073 | 1.433325 | 1.5988108 | 1.7190422 |
Pesticide (soil) | 15.523208 | 20.69761 | 25.872013 | 15.523208 | 20.69761 | 25.872013 | 15.523208 | 20.69761 | 25.872013 |
Energy | 59.835651 | 86.870388 | 112.30158 | 277.97726 | 304.81086 | 330.2091 | 302.59665 | 336.61044 | 365.40786 |
EDIP |
Total | 0.013394846 | 0.018757951 | 0.02442873 | 0.03742483 | 0.0429144 | 0.04856047 | 0.049088143 | 0.057968728 | 0.065202436 |
Global warming (GWP 100) | 0.001047775 | 0.001477754 | 0.00189988 | 0.00359432 | 0.0040296 | 0.00444857 | 0.004823125 | 0.005624618 | 0.006209534 |
Acidification | 0.000544453 | 0.000788231 | 0.00104088 | 0.00087095 | 0.00112338 | 0.00137577 | 0.001664129 | 0.002154371 | 0.002515469 |
Eutrophication | 0.003267925 | 0.004453371 | 0.00574918 | 0.00361988 | 0.00482479 | 0.00611978 | 0.006304814 | 0.008318734 | 0.00997571 |
Photochemical smog | 0.000170838 | 0.000235238 | 0.0003047 | 0.0003023 | 0.0003675 | 0.0004367 | 0.000415924 | 0.00051399 | 0.000598279 |
Ecotoxicity water chronic | 0.001493251 | 0.002078688 | 0.00284514 | 0.00456145 | 0.00519663 | 0.00595413 | 0.007208578 | 0.008596149 | 0.009714592 |
Ecotoxicity water acute | 0.001243991 | 0.001714344 | 0.0022113 | 0.00420647 | 0.0047279 | 0.00521615 | 0.006717897 | 0.00795496 | 0.008786304 |
Ecotoxicity soil chronic | 0.002577418 | 0.003584406 | 0.00468446 | 0.00595102 | 0.00695597 | 0.0080556 | 0.006466586 | 0.00761594 | 0.00878632 |
Human toxicity air | 0.000509268 | 0.000720343 | 0.00092095 | 0.00152606 | 0.00173505 | 0.00193547 | 0.001620564 | 0.001857016 | 0.002070554 |
Human toxicity water | 7.44 × 10−5 | 0.000110764 | 0.00014493 | 0.00061465 | 0.00065113 | 0.00068526 | 0.000657524 | 0.000705894 | 0.00074591 |
Human toxicity soil | 0.002465551 | 0.003594811 | 0.00462731 | 0.01217773 | 0.01330246 | 0.01433303 | 0.013209003 | 0.014627056 | 0.015799764 |
For all indicators, the results indicated that VEG patterns always had the lowest single score: LOV patterns had single scores of 3 ± 0.7 times higher than VEG patterns, and OMN patterns had single scores of 4.7 ± 1 times higher than VEG patterns, depending to the calorie intake.
3.2. “Delta” Study
The results obtained in the delta study, according to each of the above-mentioned indicators, are reported in
Table 2.
Table 2.
Delta study: total and partial environmental impacts (indicated as single score, Pt per week) of the 19% component in which the three 2400 kcal patterns differ (delta), according to each indicator.
Table 2.
Delta study: total and partial environmental impacts (indicated as single score, Pt per week) of the 19% component in which the three 2400 kcal patterns differ (delta), according to each indicator.
Pattern | VEG Delta | LOV Delta | OMN Delta |
---|
Ecoindicator99 |
Total | 0.21163256 | 1.9540345 | 3.6643576 |
Carcinogens | 8.05 × 10−5 | 0.001219979 | 0.001596435 |
Respiratory Organics | 4.01 × 10−5 | 0.000166618 | 0.000305573 |
Respiratory Inorganics | 0.021479271 | 0.09972547 | 0.24028832 |
Climate change | 0.011307043 | 0.10462142 | 0.16357382 |
Radiation | 4.92 × 10−5 | 0.000363216 | 0.000386427 |
Ozone layer | 7.65 × 10−5 | 3.15 × 10−5 | 5.91 × 10−5 |
Ecotoxicity | 0.00015814 | 0.001745867 | 0.002227464 |
Acidification/Eutrophication | 0.005841891 | 0.023727391 | 0.08568815 |
Land and water use | 0.14422255 | 0.93354814 | 2.2793129 |
Minerals | 1.37 × 10−5 | 0.000479934 | 0.000541406 |
Fossil fuels | 0.028476768 | 0.78840499 | 0.89037801 |
Ecopoint |
Total | 1966.647 | 8736.5711 | 25,386.999 |
NOx | 244.3271 | 1792.9067 | 2564.5648 |
SOx | 100.58787 | 345.87779 | 424.46498 |
NMVOC | 40.724424 | 175.43345 | 272.92316 |
NH3 | 210.51048 | 584.99251 | 3527.0838 |
Dust PM10 | 2.9942366 | 59.304326 | 68.263183 |
CO2 | 398.16059 | 3813.7786 | 5905.1117 |
Ozone layer | 0.46604541 | 1.9578271 | 3.640162 |
Pb (air) | 0.08821719 | 1.3213139 | 1.9105317 |
Cd (air) | 0.53593394 | 8.5764778 | 10.615507 |
Zn (air) | 0.092202355 | 0.8064707 | 1.5367188 |
Hg (air) | 0.17861332 | 10.371796 | 11.187239 |
COD | 1.3626347 | 22.224598 | 28.637096 |
P | 107.57917 | 249.26705 | 1025.8589 |
N | 849.72417 | 1431.9097 | 11270.471 |
Cr (water) | 0.045675248 | 1.7736143 | 2.0564881 |
Zn (water) | 0.029915182 | 0.85359468 | 1.0089572 |
Cu (water) | 0.032329539 | 1.5634239 | 1.7889283 |
Cd (water) | 0.07970724 | 0.46663514 | 0.92955853 |
Hg (water) | 0.081921167 | 5.3177828 | 5.7018097 |
Pb (water) | 0.006726089 | 0.28355506 | 0.32204421 |
Ni (water) | 0.00528008 | 0.22105271 | 0.25655257 |
AOX (water) | 0.003837047 | 0.014917741 | 0.029135601 |
Metals (soil) | 0.078326533 | 1.0618578 | 1.3636445 |
Energy | 8.9515701 | 226.28606 | 257.2731 |
EDIP |
Total | 0.003713746 | 0.027870192 | 0.042734028 |
Global warming (GWP 100) | 0.000297634 | 0.002849477 | 0.004412835 |
Acidification | 0.000112545 | 0.000447691 | 0.001467579 |
Eutrophication | 0.000333923 | 0.000705344 | 0.004129094 |
Photochemical smog | 3.79 × 10−5 | 0.000170155 | 0.000315601 |
Ecotoxicity water chronic | 0.001190023 | 0.004307961 | 0.00768123 |
Ecotoxicity water acute | 0.000872404 | 0.003885964 | 0.007087624 |
Ecotoxicity soil chronic | 0.000396519 | 0.003768079 | 0.004424933 |
Human toxicity air | 4.81 × 10−5 | 0.001062836 | 0.00118261 |
Human toxicity water | 1.70 × 10−5 | 0.000557353 | 0.000611296 |
Human toxicity soil | 0.000407688 | 0.010115332 | 0.011421227 |
For all indicators, the results of the delta study showed that, compared with the single score of the VEG pattern, the single score of the LOV pattern was up to 9.2 times higher, and the single score of the OMN pattern was up to 17.3 times higher. The single score of the delta study for the OMN pattern (2400 kcal), for each indicator, was: 3.66 (Ecoindicator99), 25,387 (Ecopoint) and 0.043 (EDIP). It was higher than (or equal to, for LOV-EDIP) the single score calculated in the whole diet study for both the other diets, that was, respectively: 0.95 (VEG) and 2.69 (LOV), calculated with the Ecoindicator99; 9,977 (VEG) and 16,700 (LOV), calculated with the Ecopoint; 0.019 (VEG) and 0.043 (LOV), calculated with the EDIP.
3.3. “Whole Diet” Study vs. “Delta” Study
It can be noticed that the animal food component in the OMN pattern, while making up only 19% of the total weight of the diet, accounted for about 73%–83% of its total environmental impact: for Ecoindicator99 the single score was 3.66 (delta) out of 4.41 (whole); for Ecopoint, 25,387 (delta) out of 33,726 (whole); for EDIP, 0.043 (delta) out of 0.058 (whole).
Other interesting results were the ratios of the single score of the delta study to the single score of the whole diet study: 0.83 (OMN), 0.73 (LOV), and 0.22 (VEG). Moreover, the ratios between the single scores of the delta study over the single score of the plant food common component of the diet (81% in mass) was shown to be 1.21 (OMN), 0.98 (LOV), and 0.30 (VEG).
3.4. Distribution of the Sources of Relative Impact within the Dietary Patterns
The different components of the overall environmental impacts, accordingly to each indicator, within the same dietary pattern, can be summarized as follows:
3.4.1. Ecoindicator99
The results obtained using Ecoindicator99 showed that the major impact, from 45% to 60% of the overall impact, always stemmed from land and water use. The second largest impact, from 25% to 50% of the total, came from energy use. The third cause of impact, from 7% to 16% of the total, was due to the emission of toxic inorganic compounds into the environment. Effects on climate change (5%–6%) and on acidification/eutrophication (2%–4%) represented another substantial impact.
3.4.2. Ecopoint
The results of the Ecopoint analysis showed that the most impacting factor, from 35% to 55% of the total, was the contamination from inorganic nitrogen and phosphorous compounds. The second major cause of impact, from 21% to 37% of the total, was the emissions into the atmosphere, while the third source of impact, from 16% to 27% of the total, was due to the emission of oxides into the atmosphere. The inclusion of N-oxides among the Greenhouse Gas (GHG) subcategories put the GHG emissions at the same level of impact of inorganic nitrogen and phosphorous compounds (34%–57%).
3.4.3. EDIP
The impacts detected by the above two indicators translated into a considerable number and variety of toxic impacts, that could be further evaluated by the EDIP indicator. Results of EDIP analysis showed that the highest impact, from 25% to 33% of the total, was due to human toxicity caused by soil contamination. The second-highest impact, from 20% to 29% of the total, was due to acute and chronic eco-toxicity of the water. The third-highest impact, from 13% to 19%, was due to chronic eco-toxicity of the soil. The fourth-highest impact, from 10% to 18%, was due to water eutrophication, while the fifth impact, from 8% to 10%, was given by various contributions to global warming.
3.5. Absolute Values of the Impacts in the Different Dietary Patterns
The above mentioned percentages represented the proportions of the various kinds of impact within the same dietary pattern, and they were very similar for all the examined dietary patterns, that is, for each dietary pattern its main impact was land and water use, then energy and so on.
But when taking into consideration the absolute values of those impacts, they varied dramatically among the various patterns. In fact, the total impact (single score) for the VEG pattern was 35% and 22%, respectively, than the one for the LOV and OMN patterns (these data apply specifically to the 2400 kcal scenario for Ecoindicator99). Therefore, even if, for example, the land and water use accounted for 50% of the impact both in VEG and in OMN diets, the absolute value in the VEG diet was 78% lower than the absolute value for the OMN diet for the same impact.
The overall results of our study showed that OMN diets had the highest impact, while VEG diets had the lowest environmental impact, independently of the calorie intake.
In most cases, the differences were just as significant also between a LOV and an OMN diet, so much so that the overall impact of a 3200 kcal LOV was always lower than that a 1600 kcal OMN one. The presence of animal food in the diet resulted to be the main impacting factor.
3.6. Subcategories of Impact
The study of the total impacts (represented by the single score,
Pt/week) included not only the analysis of some well-known, commonly used impact subcategories,
i.e., GHG, land and water use, but also other less commonly studied impact subcategories, all listed in
Table 1 and
Table 2: the various subscores of impact subcategories contributed to the final value of the single score of the respective indicator. Although more complex, the single score represents an index of the total environmental impact of food production, more accurate and comprehensive than the score of each single impact subcategory. For example, for the 2400 kcal OMN diet, the subscore for land and water use, a subcategory of Ecoindicator99, was respectively 5.92 and 2.10 times the score of the VEG and LOV patterns for the whole study (
Table 3), and 15.80 and 2.44 for the delta study (
Table 4). For comparison, the single score of the total impact category analyzed by Ecoindicator99 was 4.64 and 1.64 times for the whole study and 17.31 and 1.88 times for the delta study. It is worth to underline that in the whole diet study, land and water use subscore contributed for 45%–46% in the vegetarian patterns and 58% in the OMN patterns, to the total impact, as represented by the value of the single score (
Table 3). Similarly, a recent study conducted in Germany by Meier
et al. [
42], which analyzed consumption data derived from a National Nutrition Survey, showed a land-saving potential effect of plant-based diets, which was maximum for VEG diets.
Table 3.
Whole diet study: land and water use, and GHG subscores (indicated as single score, Pt per week) of the three complete food patterns, according to each indicator.
Table 3.
Whole diet study: land and water use, and GHG subscores (indicated as single score, Pt per week) of the three complete food patterns, according to each indicator.
Pattern | VEG | LOV | OM |
---|
kcal | 1600 | 2400 | 3200 | 1600 | 2400 | 3200 | 1600 | 2400 | 3200 |
Ecoindicator99 |
TOTAL single score | 0.64800 | 0.94997 | 1.30716 | 2.38594 | 2.69237 | 3.04923 | 3.71226 | 4.40574 | 4.93413 |
versus VEG | - | - | - | - | - | - | 573% | 464% | 377% |
versus LOV | - | - | - | - | - | - | 156% | 164% | 162% |
versus OMN | 17% | 22% | 26% | 64% | 61% | 62% | - | - | - |
Land and water use subscore | 0.29043 | 0.43349 | 0.63636 | 1.07649 | 1.22282 | 1.42569 | 2.11707 | 2.56571 | 2.90097 |
versus TOTAL | 45% | 46% | 49% | 45% | 45% | 47% | 57% | 58% | 59% |
versus VEG | - | - | - | - | - | - | 729% | 592% | 456% |
versus LOV | - | - | - | - | - | - | 197% | 210% | 203% |
versus OMN | 14% | 17% | 22% | 51% | 48% | 49% | - | - | - |
Climate change subscore | 0.03919 | 0.05521 | 0.07097 | 0.13230 | 0.14853 | 0.16417 | 0.17864 | 0.20869 | 0.23059 |
versus TOTAL | 6% | 6% | 5% | 6% | 6% | 5% | 5% | 5% | 5% |
versus VEG | - | - | - | - | - | - | 456% | 378% | 325% |
versus LOV | - | - | - | - | - | - | 135% | 141% | 140% |
versus OMN | 22% | 26% | 31% | 74% | 71% | 71% | - | - | - |
Ecopoint |
TOTAL single score | 6962.1 | 9977.3 | 13,418.1 | 13,599.6 | 16,700.3 | 20,134.6 | 26,697.4 | 33,726.7 | 38,929.9 |
versus VEG | - | - | - | - | - | - | 383% | 338% | 290% |
versus LOV | - | - | - | - | - | - | 196% | 202% | 193% |
versus OMN | 26% | 30% | 34% | 51% | 50% | 52% | - | - | - |
Greenhouse Gas (GHG) subscore | 2707.6 | 3823.5 | 4926.8 | 7740.8 | 8866.0 | 9963.3 | 10,042.4 | 11,850.4 | 13,260.9 |
versus TOTAL | 39% | 38% | 37% | 57% | 53% | 49% | 38% | 35% | 34% |
versus VEG | - | - | - | - | - | - | 371% | 310% | 269% |
versus LOV | - | - | - | - | - | - | 130% | 134% | 133% |
versus OMN | 27% | 32% | 37% | 77% | 75% | 75% | - | - | - |
EDIP |
TOTAL single score | 0.01339 | 0.01876 | 0.02443 | 0.03742 | 0.04291 | 0.04856 | 0.04909 | 0.05797 | 0.06520 |
versus VEG | - | - | - | - | - | - | 366% | 309% | 267% |
versus LOV | - | - | - | - | - | - | 131% | 135% | 134% |
versus OMN | 27% | 32% | 37% | 76% | 74% | 74% | - | - | - |
Global warming (GWP 100) subscore | 0.00105 | 0.00148 | 0.00190 | 0.00359 | 0.00403 | 0.00445 | 0.00482 | 0.00562 | 0.00621 |
versus TOTAL | 8% | 8% | 8% | 10% | 9% | 9% | 10% | 10% | 10% |
versus VEG | - | - | - | - | - | - | 460% | 381% | 327% |
versus LOV | - | - | - | - | - | - | 134% | 140% | 140% |
versus OMN | 22% | 26% | 31% | 75% | 72% | 72% | - | - | - |
Table 4.
Delta study: land & water use and GHG subscores (indicated as single score, Pt per week) of the 19% component in which the three 2400 kcal patterns differ (delta), according to each indicator.
Table 4.
Delta study: land & water use and GHG subscores (indicated as single score, Pt per week) of the 19% component in which the three 2400 kcal patterns differ (delta), according to each indicator.
Pattern | VEG | LOV | OMN |
---|
Ecoindicator99 |
TOTAL single score | 0.21163 | 1.95403 | 3.66436 |
versus VEG | - | - | 1731% |
versus LOV | - | - | 188% |
versus OMN | 6% | 53% | - |
Land and water use subscore | 0.14422 | 0.93355 | 2.27931 |
versus TOTAL | 68% | 48% | 62% |
versus VEG | - | - | 1580% |
versus LOV | - | - | 244% |
versus OMN | 6% | 41% | - |
Climate change subscore | 0.01131 | 0.10462 | 0.16357 |
versus TOTAL | 5% | 5% | 4% |
versus VEG | - | - | 1447% |
versus LOV | - | - | 156% |
versus OMN | 7% | 64% | - |
Ecopoint |
TOTAL single score | 1966.6 | 8736.5 | 25,386.9 |
versus VEG | - | - | 1291% |
versus LOV | - | - | 291% |
versus OMN | 8% | 34% | - |
Greenhouse Gas (GHG) subscore | 683.2 | 5782.1 | 8742.5 |
versus TOTAL | 35% | 66% | 34% |
versus VEG | - | - | 1280% |
versus LOV | - | - | 151% |
versus OMN | 8% | 66% | - |
EDIP |
TOTAL single score | 0.00371 | 0.02787 | 0.04273 |
versus VEG | - | - | 1151% |
versus LOV | - | - | 153% |
versus OMN | 9% | 65% | - |
Global warming (GWP 100) subscore | 0.00030 | 0.00285 | 0.00441 |
versus TOTAL | 8% | 10% | 10% |
versus VEG | - | - | 1483% |
versus LOV | - | - | 155% |
versus OMN | 7% | 65% | - |
GHG emissions (calculated as GHG emissions in kilograms of carbon dioxide equivalents, kgCO
2e), have been assessed in two recent studies in UK and Northern USA [
43,
44]. In the UK study, the real 2000 kcal diet of 55,504 subjects was analyzed [
43], and the average production of kgCO
2e/day resulted to be, in medium-meat-eaters, 1.95 and 1.48 times the amounts produced by VEG and LOV subjects, respectively. Soret [
44] reported similar results for the average emissions of CO
2e per year in 73,308 American nonvegetarians, respectively 1.41 and 1.28 times the amounts produced by vegetarians and semivegetarians, for an average calorie intake of about 1700 kcal.
In our LCA study, GHG emissions were analyzed by the indicators Ecoindicator99 (climate change subcategory), Ecopoint (NO
x, NMVOC-Non Methane Volatile Organic Compounds, CO
2 subcategories) and EDIP (global warming subcategory), and contributed to the single score of the respective indicator for 5%–6% (Ecoindicator99), 34%–57% (Ecopoint) and 8%–10% (EDIP). For the lower calorie patterns, the 1600 kcal diets, the subscore for GHG emissions in OMN pattern was respectively: 4.56 and 1.35 times the score of the VEG and LOV patterns in Ecoindicator99; 3.71 and 1.30 times the score of the VEG and LOV patterns in Ecopoint; 4.60 and 1.34 times the score of the VEG and LOV patterns in EDIP. Again, it is worthwhile to underline that in the 1600 kcal OMN pattern, the single score of the total impact categories was 5.73 and 1.56 times (Ecoindicator99), 3.83 and 1.96 times (Ecopoint) and 3.66 and 1.31 times (EDIP) the single score of the VEG and LOV patterns, respectively. The data referred to the above mentioned subcategories, for all the dietary patterns and all the indicators, were summarized in
Table 3 and
Table 4.
Although the importance of the above mentioned studies relies on the analysis of real diets, they have been performed with an approach different from the present study. In fact, our study evaluated theoretical diets, so we did not consider any difference in geographical zone or transportation, import-export food fluxes and related emissions during cooking and storing in the household/in restaurants. For these reasons, we think that a comparison among the results of the different studies is not possible, even if these studies on real diets confirm the lowest environmental impact of plant based diets: future studies, performed in other countries and evaluating the total impacts, are warranted.