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Following a healthy and sustainable diet is not as easy as it might seem.
The principle of eating less animal-based products and more plant-based
products does not, by definition, impact the environment any less.
This article uses calculations from the Optimeal® program to identify
sustainability principles for our diets that do make a difference.
TEXT LIONEL VAN EST & LUUK BLOM (NUTRICON, NETHERLANDS), STEPHAN PETERS (NZO DUTCH DAIRY ASSOCIATION, NETHERLANDS)
ILLUSTRATION DANNES WEGMAN
Decreasing the environmental
footprint of our diet
RESEARCH
2
Figure 1. Total carbon emissions from the average household (2.2 people). Source: Milieu Centraal website
Our food’s journey from
the farm to our plate
costs energy and aects
the environment. Over
the last decade, attention
has grown for more
environmentally-friendly food production.
However, consumer food choices also
significantly influence the total environ-
mental impact of our diet. Excessive food
consumption and diets that entail large
quantities of processed foods have a
higher environmental footprint than, for
instance, diets which include water as the
only beverage or which involve no meat.
The total environmental footprint of our
diet, therefore, is a mix between produc-
tion methods and consumer choices.
Politicians, policymakers, scientists and
nutrition authorities like the Netherlands
Nutrition Centre agree on one important
condition for transitioning towards a more
environmentally-friendly diet: it must be
healthy. The human body requires a great
deal of nutrients, and these nutrients come
from a large variety of foods. Variation in
the diet is essential for good health, and
a more sustainable diet must provide
everything the body needs.
Environmental impact
Transitioning towards a more sustainable
diet generally follows the following five
principles:
1. Eat less animal-based and more
plant-based products
2. Eat more locally-produced food
3. Decrease your carbon footprint
4. Reduce food waste
5. Eat less processed food
This article addresses the first, third, and
fifth principles and calculates the environ-
mental impact of dierent types of diets.
If not stated otherwise, all diets provide
all nutrients required by ocial dietary
guidelines and are within normal ranges
of saturated fat, salt, etc. Several calcula-
tion models are available to determine the
environmental impact of food. One such
method is Optimeal®, a quadratic calcula-
tion model developed by Blonk Consultants
(Netherlands) and the Netherlands Nutri-
tion Centre. Optimeal® has gathered data
on the nutritional content and environ-
mental eects (carbon emissions, land
and water use) of 208 products regularly
consumed in the Netherlands. Life-cycle
assessments (LCAs) are used to calculate
the environmental impact of each product,
from production to consumption.
Climate change
Most sustainability recommendations
focus on lowering carbon emissions.
Human carbon emissions are the major
cause of climate change. According to the
Dutch semi-governmental environmental
agency Milieu Centraal, a household pro-
duces 23 tons of carbon emissions every
year. Figure 1 breaks down the household
activities that cause emissions and to what
extent. These figures reveal that about
a quarter of our total emissions come
from food.
Carbon emissions from food
According to Milieu Centraal, every
household (averaging 2.18 people in the
Netherlands) is responsible for 5.6 tons
of emissions from food. This number does
not include the energy used to conserve
(i.e. refrigerate or freeze) or prepare food,
and can be broken down into the
following four food groups:
1. Meat and fish 1.8 tons CO2
2. Dairy and eggs 1.1 tons CO2
3. Vegetables and fruits 0.5 tons CO2
4. All other products 2.2 tons CO2
These figures show that 2,9 tons CO2 come
from animal-based products – in other
words, 52% of a household diet and 12.6%
of total annual household emissions.
For perspective, a return flight from the
Netherlands to Thailand releases 5.4 tons
of carbon emissions.
Theory vs. reality
Theoretically, carbon emissions from the
human diet could be reduced by 2.9 tons by
eating vegan. But in actuality, the calories
and nutrients lost by avoiding animal
products must be compensated by other,
plant-based products – and these have
an environmental footprint as well. If
an individual decides not to eat certain
animal products based on environmental
concerns, they must make sure that their
new diet still lowers their environmental
footprint. According to the Dutch environ-
3
0
10
20
30
40
50
Beef rump steak
Gouda cheese 48+
Pork shoulder chops
Chicken fillet
Pangasius
Chicken egg
Herring
Tomato raw
Whole milk
Yoghurt full fat
Chickpeas
Banana
Bread whole meal
Carbon footprint
CO2eq / kg
0
10
20
30
40
50
60
70
80
Beef rump steak
Pork shoulder chops
Pangasius
Chicken fillet
Gouda cheese 48+
Chicken egg
Chickpeas
Whole milk
Yoghurt full fat
Bread whole meal
Banana
Tomato raw
Herring
Land use
m2*a / kg
mental agency Natuur en Milieu, an
individual can decrease their carbon
emissions by 1 ton per year by switching
to a vegetarian diet.
Carbon emissions products
In general, animal products have higher
carbon emissions than plant-based pro-
ducts. Figure 2 provides an overview of
carbon emissions per kilogram of product.
The big outlier here is beef (red meat),
mainly from beef cattle. Beef’s high carbon
emissions are caused by several factors; the
calculations used by Optimeal® are the
sum of all emissions from meat consumed
in the Netherlands, whether from imported
meat or meat produced in the Netherlands
from beef or dairy cattle.
Figure 3 provides an overview of land use
per kilogram of product. The production
of beef is also the biggest culprit here.
Pangasius, a tropical fish, takes a sur-
prising third place on the list. Pangasius
is farmed, not wild, and is produced
mainly in Vietnam and Thailand. In the
LCA of pangasius, it is its feed that places
it high on the list of land users.
Health
The apparent consensus to reduce our
diet’s environmental footprint is to eat
less meat and fish and more plant-based
products. Indeed, figures 2 and 3 seem
to support this. However, our diet should
not become unhealthy in the process.
The alternative foods must still provide
the essential nutrients our bodies need.
Furthermore, not every food from animal
origins has the same environmental foot-
print; the same holds for fruits and vegeta-
bles. For example, a banana imported from
South America has a bigger environmental
footprint than a Dutch apple, simply thanks
to transport. When considering replacing
certain diets with others, it is important to
look closely at the environmental footprint
of individual products.
Product replacement
Optimeal® has calculated the eects of
product replacement on the environmental
footprint of a diet. As a starting point,
Optimeal® looks at the average Dutch
diet based on the Dutch National Food
Consumption Survey (VCP). Subsequently,
food groups are changed in the diet with
steps of 20 grams. For every 20 grams,
Optimeal® has calculated a similar but
alternative diet that complies with all
dietary reference values for nutrients and
then calculated its environmental impact.
This model reveals how replacing certain
parts of a diet aects the diet’s footprint.
Now, for each food group, it is possible
to see its carbon footprint and land use
(figures 4 and 5) in increments of 20 grams.
Replacing dairy
These figures clearly reveal the striking
impact of beef consumption on the environ-
ment – the more beef is consumed, the
higher carbon emissions and land use
become. Like beef, dairy also comes
from animals, but, unlike beef, increasing
amounts of dairy consumption have
negligible added eect on the environment.
Why is this? When omitting dairy, which is
very nutrient rich, the nutrients have to be
provided by other products. For example,
calcium can come from eating more vege-
tables like spinach or broccoli, protein
from more eggs or legumes. To get the
nutrients provided by dairy, an individual
must consume much more fruit and
vegetables than the recommended daily
portions. When you add up the environ-
mental eects of these replacements, the
same carbon emissions and land use are
the result. Increasing the amount of fruit
and vegetables in the diet does not result
in a lower environmental impact. This
is surprising given the widely accepted
principle that plant-based products should
replace meat in the diet. However, most
vegetables are relatively poor in nutrients.
Figure 2. Carbon emissions by kilogram of product produced, based on Optimeal® calculations
Figure 3. Land use by kilogram of product produced, based on Optimeal® calculations
RESEARCH
4
You need a lot more of them to replace the
daily nutrients you can get from dairy. As a
result, Optimeal® has to increase vegetable
intake by considerable amounts in order to
reach the calcium recommendations. This
is why these higher amounts of vegetables
have the same environmental impact as
that of nutrient-rich dairy. Obviously, since
Optimeal® is only a nutrient calculation
model, the health eects of vegetables,
dairy and other products on e.g. non-
communicable diseases are not taken
into account.
Optimeal® conclusions
Fruit and vegetables are healthy, but not
necessarily because of their nutritional
content. Actually, fruit and vegetables are
quite low in nutrients. When increasing
consumption amounts of fruit and
vegetables in Optimeal®, the program has
to turn to nutrient-dense products to reach
a healthy diet that complies with dietary
recommendations. In our approach,
Optimeal® uses animal products, since
these are the most nutrient-dense.
As seen in figures 4 and 5, there are two
plant-based food groups that do have a
desirable eect on the environmental
footprint: bread and nuts and seeds. These
two food groups contain relatively high
amounts of nutrients and their environ-
mental impact declines as consumption
increases. However, for nuts and seeds
as well as cheese, Optimeal® does not go
further than 140 and 240 grams respec-
tively. This is due to the fact that when
these products are increased to higher
consumption amounts, Optimeal® cannot
calculate an alternative diet because the
upper amount for saturated fat (10 en%)
is reached.
Optimeal® concludes that the sustainable
principle to eat less animal-based products
and more plant-based products does not
automatically result in a more environ-
mentally-friendly diet. Shifting between
basic food groups to obtain a more sus-
tainable diet gives disappointing results.
We can only conclude that consuming
more nuts, seeds, and bread, and eating
less beef, will improve a diet’s environ-
mental footprint.
The “data gap”
A downside to working with models like
Optimeal® is that such models contain
environmental data on a limited number
of products. Optimeal® includes 208 prod-
ucts, but Dutch supermarkets sell tens of
When you add up the environmental
effects of products that replace dairy,
the same carbon emissions and land
use are the result
5
Carbon footprint (kg CO2e / day)
Food groups (gram / day)
Vegetables
Fruit
Meat
Fish
Dairy
Cheese
Bread
Potatoes, past
Beans/pulses
Nuts/seeds
Non-specified
Food groups
600
560
520
480
440
400
360
320
280
240
200
160
120
80
40
0
2
3
4
5
6
6
6
6
10
Land use (m2 * year / day)
Food group (gram / day)
Vegetables
Fruit
Meat
Fish
Dairy
Cheese
Bread
Potatoes, past
Beans/pulses
Nuts/seeds
Non-specified
Food groups
600
560
520
480
440
400
360
320
280
240
200
160
120
80
40
0
2
3
4
5
6
6
6
6
10
thousands. Furthermore, environmental
data is usually related to single types of
foods, and LCAs can be determined
relatively easily from this information,
developing a picture of a food’s carbon
emissions and land use. Optimeal® there-
fore mostly consists of the basic food groups
and not of processed foods or foods made
from many dierent ingredients. There is
no data on ready-to-eat meals, candy, or
snacks, and such products have a higher
environmental impact than basic food
products. Models like Optimeal® must
therefore be used with caution: “you can
only manage what you can measure”.
Wheel of Five diet
The Dutch dietary guidelines are repre-
sented in the Wheel of Five (Schijf van
Vijf) developed by the Netherlands
Nutrition Centre. The new Wheel of Five
launched in 2016 provides ten dierent
daily menus as examples of how you can
meet these guidelines in your daily diet.
One would expect that more complex,
processed foods have a higher environmen-
tal footprint than the basic food groups.
If so, the rule of thumb for eating in a
more sustainable way would be to eat less
processed food and to follow the recommen-
dations of the Wheel of Five, assuming it,
too, is sustainable. To find out, we entered
all ten Wheel of Five daily menus for a
35-year-old woman (2000 kcal per day,
see www.voedingscentrum.nl) into
Optimeal® and calculated their carbon
emissions and land use. We then compared
these daily menus to the average Dutch
diet (according to RIVM’s Dutch National
Food Consumption Survey (VCP)), recal-
culating it to 2000 kcal a day for compari-
son. Results are shown in table 1, with the
daily menus sorted from highest to lowest
carbon emissions.
Footprints of daily menus
We often hear that we eat too few fruit
and vegetables and too much meat and
snacks. This conclusion is based on the
Dutch National Food Consumption Survey
(VCP). We therefore assumed that the
environmental impact of the average
Dutch diet would be higher than the
healthier Wheel of Five daily menus. The
menu 'No meat today' put together by the
Netherlands Nutrition Centre is meant to
encourage consumers to skip meat one
day a week; 'Crazy about fruit and vegeta-
bles' and 'Taste the sun' menus are higher
in exotic fruits. If eating less meat and
more plant-based products is truly more
sustainable, then these daily menus would
have a lower environmental impact than
the more Dutch 'I love Holland' diet of
mostly meat, cheese and other dairy. How-
ever, table 1 reveals that half of the Wheel
of Five daily menus have a higher environ-
mental impact than the average Dutch
diet, even 'No meat today'. Most striking is
that the 'I love Holland' daily menu has the
lowest carbon emissions and land use of
all. This daily menu is based on what the
Dutch most commonly eat: meat, dairy
(350 grams), fruit and vegetables from
Dutch farms. Even the Netherlands Nutrition
Centre finds it dicult to make a more
sustainable diet based on the principle of
eating less animal-based and more plant-
based products. How can these surprising
results be explained? Without going into
too much detail, the following examples
can help illustrate. Daily menus that
contain lots of exotic fruits entail more
land use and carbon emissions. The LCAs
of exotic fruits logically have more environ-
mental impact because they must be trans-
ported, conserved, etc. A Dutch apple or
Figure 4
Figure 5
Figure 4 and figure 5. Environmental impact on
carbon emissions and land-use when replacing
certain parts of the diet. For every 20 grams,
Optimeal® has calculated a similar but alternative
diet that complies with all dietary reference values
for nutrients. The environmental impact of these
alternative diets is calculated and shown per food
group in the coloured lines. Non-specified is the
impact of foods that do not belong to basic
foodstuffs. See text for further information.
RESEARCH
6
pear can, in theory, go directly from the
tree to the supermarket. In conclusion,
it is not as easy as it seems to follow a more
sustainable diet just by living according to
eating less meat and other animal products
and more plant-based products.
Fewer animal products
In all its calculations up to now, Optimeal®
has considered an alternative diet that looks
most like the one consumers are used to.
This is what the principle of quadratic
modeling is about. We also used Optimeal®
to calculate the environmental eects of
omitting entire animal food groups. The
results are shown in table 2. When the
animal food groups in the left column
are omitted, Optimeal® calculates an alter-
native diet that meets all nutrient require-
ments. Avoiding all dairy products hardly
changes the environmental footprint; this
corresponds with our earlier calculations.
Avoiding meat, on the other hand, could
potentially impact the footprint a great
deal: approximately 25% fewer carbon
emissions by omitting meat and more than
40% by going vegan. But such major
dietary changes are not welcomed by
most consumers, at least not yet.
Eating less
The most logical advice for reducing
environ mental impact is to eat less. This is
why carbon emissions of the VCP diet are
calculated at dierent calorie intakes (P5,
P25, P50, P75, and P95) for both men and
women aged 31 to 50. These diets are opti-
mized to meet the Wheel of Five guidelines.
Results for women and men are presented
in tables 3 and 4 respectively. For the P5
intake level in women, an optimal diet
cannot be calculated because of Optimeal®’s
minimum calorie consumption requirement.
The tables demonstrate that for those who
eat too much, eating less will reduce their
environmental footprint. For example,
a man who eats too much (P95) who
switches to the recommended amount
(P50) can reduce his carbon emissions
by 36.3-47.5%.
Not too varied
As we saw in the Wheel of Five daily
menus, even those with lots of fruit and
vegetables can have a major impact on
the environment. If you want to eat more
plant-based products, it is best to choose
products from the Netherlands. This is
why, from an environmental standpoint,
the 'I love Holland' daily menu is the most
beneficial; it entails meat and dairy products
that are made nearby. But if you eat lots of
exotic fruit and vegetables, it is dicult to
achieve a sustainable footprint. This is a
dilemma in food nutrition. Eating a varied
diet seems to be at odds with eating sus-
Example daily menus
Carbon emissions (kg CO2 eq/dag)
Land use (m2*year/dag)
Taste the sun 5,10 4,54
Crazy about fruit and
vegetables
5,04 4,02
Power food 3,89 3,54
Colors of Marrakesh 3,82 3,48
No meat today 3,66 2,74
Avg. 35-year-old woman
(VCP)
3,62 3,98
Fiber boost 3,48 2,98
Fresh from the market 3,32 3,16
No fat! 3,29 2,81
Take your time 3,19 3,70
I love Holland 3,13 2,75
Table 1. Carbon emissions and land use of Netherlands Nutrition Centre daily menus and the average
Dutch diet (Avg. 35-year-old woman (VCP)), recalculated for 2000 kcal
Most striking is that the 'I love Holland'
daily menu has the lowest carbon
emissions and land use of all Wheel
of Five menus
7
tainably. In short, with a varied diet you
must also think in terms of excess.
RIVM reports
The results presented in this article are in
line with RIVM’s own research. In its 2016
report Milieubelasting van de voedsel-
consumptie in Nederland (“Environmental
impact of food consumption in the Nether-
lands”), RIVM also found that sustainable
eating requires a more nuanced approach.
Using the Optimeal® calculations, RIVM
concluded the following:
• Fruit and vegetables from the Nether-
lands have a lower environmental foot-
print than imported fruit and vegetables
• This does not apply to crops from Dutch
greenhouses, which have a higher
impact on the environment
• Eating less red meat (beef) reduces
environmental impact
The more recent 2017 RIVM report Wat
ligt er op ons bord (“What’s on our plate”)
reinforces these conclusions. In this
report, RIVM recommends for the first
time that eating less is the first major step
towards a sustainable diet. Once this step
is taken, we can examine other ways to
reduce our environmental footprint by
making changes in our staple foods.
Points for discussion
For the purposes of this article, we worked
with Optimeal®, a quadratic programming
model used to calculate the environmental
impact of food and dietary changes. No steps
were taken to validate the calculations, but
we used the same version of Optimeal®
that was used by the Netherlands Nutrition
Centre and RIVM. Such models always
come with their shortcomings and limita-
tions, as do the starting points with which
they work. In replacing products, we
always looked for an alternative diet that
came as close as possible to the consumer’s
experience, thus making it more acceptable.
One major downside to this type of calcu-
lation model is the limited number of foods
for which environmental data is available
– the “data gap” discussed above. Data is
especially lacking for more unhealthy and
non-staple foods. For this reason, models
like Optimeal® are not actually equipped
to base robust recommendations upon.
However, the Optimeal® model is used
by organizations like the Netherlands
Nutrition Centre and RIVM to calculate
the values of daily menus. The model was
apparently not used to establish the new
Wheel of Five daily menus which accom-
panied the Wheel of Five last year. Half of
these daily menus have a higher environ-
mental impact than the average VCP diet.
This illustrates that the principle to eat
less animal-based products and more
plant-based products is not necessarily
the way towards a more sustainable diet.
Carbon emissions (kg CO2 eq/dag) Land use (m2*year/dag)
Optimal average diet 3,67 (100%) 4,00 (100%)
No dairy 3,53 (96,2%) 3,64 (91%)
No meat, fish, or eggs 2,90 (79%) 3,24 (81%)
No meat or dairy 2,84 (77,4%) 2,63 (65,7%)
No meat, eggs, or dairy 2,78 (75,7%) 2,51 (62,7%)
No meat or fish 2,74 (74,7%) 3,20 (80%)
No meat 2,73 (74,4%) 2,81 (70,25%)
No meat, fish, eggs, or dairy
2,37 (64,6%) 2,47 (61,7%)
No meat, fish, or dairy 2,27 (61,8%) 2,55 (63,7%)
kcal (% compared to current diet P50) Current diet Optimized diet
P5 1,361 (69,6%) 2,52 (69,6%) Niet genoeg Kcal
P25 1,700 (86,9%) 3,15 (86,9%) 3,38 (92,3%)
P50 1,956 (100%) 3,62 (100%) 3.66 (100%)
P75 2,227 (113,8%) 4,12 (113,8%) 3,99 (109%)
P95 2,644 (135,2%) 4,89 (135,2%) 3,54 (96,7%)
kcal (% compared to current diet P50) Current diet Optimized diet
P5 1848 (69,8%) 3,15 (69,8%) 2,86 (74,7%)
P25 2299 (86,8%) 3,92 (86,8%) 3,36 (87,7%)
P50 2647 (100%) 4,52 (100%) 3,83 (100%)
P75 3022 (114,2%) 5,16 (114,2%) 4,36 (113,8%)
P95 3611 (136,4%) 6,16 (136,4%) 5,65 (147,5%)
Table 2. Effects on climate change (in percentages) from limiting animal-based food groups
Tables 3 (women) and 4 (men). Carbon emissions at several calorie intake levels (P5, P25, P50, P75
and P95) corresponding to the VCP quantities (RIVM 2011). See text for explanations
Table 3
Table 4
If you eat lots of exotic fruit and
vegetables, it is difficult to achieve a
sustainable footprint
RESEARCH
8
Conclusions
This article provides us with a number of
simple conclusions. A sustainable diet
entails the following:
• Eating less
• Eating less red and processed meat
• Drinking less soda and fewer alcoholic
beverages
• Eating less candy and fewer snacks
(recommendation from the authors)
• Eating less processed food (recommen-
dation from the authors)
• Eating more bread
• Eating more fruits and vegetables from
Dutch farms
• Keeping dairy consumption at its
current level
This study and RIVM’s reports also make
another important conclusion: The
science behind sustainable and healthy
References
1 Milieubelasting van de voedselconsumptie in Nederland (2016). RIVM report 2016-0074.
2 Wat ligt er op ons bord (2017). RIVM report 2016-0200
The calculations in this article were made by
Nutricon, a nutrition consultancy focused on
the food industry. In addition to its nutritional
support, Nutricon offers a combination of
nutritional expertise and ICT.
diets is still very much in development.
This means that any advice from such
research must be examined with a critical
eye. Finally, it is important that the environ-
mental footprint of our diet is seen in the
right perspective. Other aspects of our
lifestyle (see figure 1) have an even larger
impact on the environment – a flight to
South Africa for vacation can undo an
entire year’s worth of environmental
benefits from a vegetarian diet.
The principle to eat less animal-based and more
plant-based products is not necessarily the way
towards a more sustainable diet
9