Dr Martin Juneau, M.D., FRCP

Cardiologue, directeur de l'Observatoire de la prévention de l'Institut de Cardiologie de Montréal. Professeur titulaire de clinique, Faculté de médecine de l'Université de Montréal. / Cardiologist and Director of Prevention Watch, Montreal Heart Institute. Clinical Professor, Faculty of Medicine, University of Montreal.

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6 January 2026
Eat better, pollute less

Overview

  • Food production is responsible for approximately 30% of all greenhouse gas (GHG) emissions, with the vast majority of these emissions coming from ruminant livestock farming.
  • A diet primarily based on plant-based foods is associated with a 50% reduction in these GHG emissions.
  • Studies show that this diet also reduces premature mortality, and its adoption would therefore lead to mutually beneficial outcomes for human health and the environment.

It is well established that increasing dietary intake of plant-based foods such as fruits, vegetables, legumes, nuts, and seeds is associated with a reduced risk of developing several chronic diseases, including cardiovascular disease, type 2 diabetes, and certain types of cancer.

Another intrinsic and infrequently discussed benefit of a high intake of plant-based foods is its potential to significantly reduce greenhouse gas (GHG) emissions associated with food production. Globally, it is estimated that approximately 25% (and up to 33% if food waste is taken into account) of all GHG emissions come from food production and distribution, with the food sector involved in animal protein production being solely responsible for half of these GHG emissions. This is primarily due to methane produced by livestock and aquaculture, which absorbs heat 28 times more effectively than CO2.

A good way to visualize the impact of livestock farming on greenhouse gas (GHG) production is to compare the emissions associated with different animal and plant-based foods based on their protein content (Figure 1). These comparisons clearly show that livestock products, beef in particular, are a much larger source of GHGs than plant-based foods: for example, producing each gram of beef protein generates approximately 250 times more GHGs than the same amount of protein from legumes. Given that two-thirds of Canadians’ daily protein consumption comes from animal sources (meat, eggs, and dairy products), reducing our intake of these foods in favour of plant-based options is a concrete way to lessen the environmental impact of what we eat.

Figure 1. Comparison of GHG emissions generated during the production of animal and plant proteins. Global greenhouse gas emissions are expressed in CO2 equivalents (CO2eq), i.e., by multiplying the quantities of the different GHGs (methane, nitrous oxide) by their warming potential relative to CO2 (28 times for methane and 298 times for nitrous oxide over a 100-year period). Note the significant share of emissions related to enteric fermentation in ruminants (cattle, in particular) and to manure management in the meat and poultry industry. For fish and seafood, it is primarily the decomposition of organic matter in aquaculture tanks and ponds that releases GHGs, mainly in the form of methane, while trawling causes pollution due to the carbon dioxide released during the disturbance of the seabed. Adapted from Tilman and Clark (2014).

The Planetary Health Diet combines health promotion and environmental awareness

One of the best examples of the merits of this approach is the Planetary Health Diet, developed by a multidisciplinary group of experts overseen by the British medical journal The Lancet (EAT-Lancet Commission). Fundamentally, this diet aims to promote human health, which is why it prioritizes a high intake of plant-based foods such as whole grains, fruits, vegetables, nuts, and legumes. Animal-based foods, on the other hand, occupy a place in this diet ranging from moderate (fish, eggs, dairy products) to low (meat, especially red meat) (Table 1). Overall, approximately 53% of calories come from complex carbohydrates, 35% from fats (mainly unsaturated), and 15% from protein, which roughly corresponds to the reference values ​​of Canada’s Food Guide. It should also be noted that the amount of protein provided by plants is greater than the minimum required to cover basic needs (10% of calories) and allows an adequate intake of all essential amino acids.

ComponentsRecommended intake
(g /day per 2500 kcal)
Criteria for maximal PHD score (g/day)*Nutritional and environmental justifications
Plant foods
1. Whole grains210 (20-50 % of daily energy intake)≥ 75 g/d (F)
≥ 90 g /d (M)		Consuming whole grains, but not refined grains, improves lipid profiles and is associated with a reduced risk of obesity, type 2 diabetes , coronary heart disease, colorectal cancer, and overall mortality.
Cereal production also generates approximately 30 times less greenhouse gas emissions than livestock farming.
2. Tubers (e.g. potatoes)50 (0-100)≤ 50Although potato cultivation has a relatively low GHG footprint, similar to that of cereals, the consumption of starchy vegetables is associated with a higher risk of excess weight and of type 2 diabetes, compared to whole grains or non-starchy vegetables. This association appears to be stronger, however, for fried potatoes than for plain potatoes.
3. Vegetables

4. Fruits		300 (200-600)

200 (100-300)		≥ 300

≥ 200		In addition to their positive impact on greenhouse gas emissions, fruits and vegetables are an essential source of numerous nutrients and phytochemicals. Their consumption is inversely proportional to the risks of weight gain, type 2 diabetes , coronary heart disease, certain cancers (such as breast cancer), cognitive decline and overall mortality.
5. Tree nuts and peanuts

6.Legumes (e.g., soy, beans, lentils, peas) and seeds (e.g., flaxseed, chia)		50 (0-75)

75 (0-100)		≥ 50

≥ 75		Nuts, legumes, and seeds provide unsaturated fats, fiber, numerous micronutrients, and are excellent sources of protein, while generating approximately 250 times fewer greenhouse gas emissions than red meat. They have beneficial effects on blood lipids, and their consumption has been associated with a reduced risk of type 2 diabetes, coronary heart disease and overall mortality.
Animal foods
7. Dairy250 (0-500)≤ 250Milk and dairy products have good nutritional value, but are high in saturated fats and raise LDL cholesterol compared to unsaturated vegetable oils. However, some data suggest that consuming yogurt, and perhaps other fermented products, may be associated with a reduced risk of type 2 diabetes.
8. Poultry30 (0-60)
(2 servings per week)
≤ 30Poultry meat has a polyunsaturated fat composition that falls between that of red meat and plant-based protein sources. Its greenhouse gas emissions are also intermediate, i.e. lower than that of red meat but higher than that of plant-based protein sources. In general, poultry consumption is not associated with an increased risk of chronic diseases and it is suggested that poultry be preferred over red meat.
9. Fish and seafood30 (0-100)
(2 servings per week)
≥ 30Fish, shellfish, and other foods of aquatic animal origin are particularly important as a source of omega-3 fatty acids, which have been linked in several studies to a reduced risk of cardiovascular disease (but not in supplement form). Although these foods have a high greenhouse gas emissions footprint, it appears that their cardioprotective effects do not require a high intake, at a maximum of just two 100g portions per week.
10. Eggs15 (0-25)
(2 per week)
≤ 15Eggs are a concentrated source of protein and essential nutrients, but are also high in dietary cholesterol. Nevertheless, most studies do not report a significant association between moderate egg consumption and the risk of cardiovascular disease. .
11. Red/processed meat (beef, lamb, pork)15 (0-30)
(1 swerving per week)
≤ 15Red meat is rich in protein, but also high in saturated fat and cholesterol, and low in essential polyunsaturated fatty acids.
Compared to plant-based protein sources (e.g., nuts, soy, and other legumes), red meat consumption increases LDL cholesterol levels and is associated with an increased risk of coronary heart disease, type 2 diabetes , colorectal cancer, dementia and premature death, particularly with processed red meats (e.g., deli meats).
In addition to these negative health effects, red meat production also generates the highest greenhouse gas emissions.
Fat and sugar
12. Added unsaturated fats (e.g., olive, canola oils)

13.Added saturated fats (butter, lard, tallow, palm or coconut oils)		40 (0-80)
(5-20 % of total energy intake)

12 (0-12)		≥ 20 % of total energy intake

0% of total energy intake		Unlike butter and other sources of saturated fat that raise LDL cholesterol levels, vegetable oils primarily contain unsaturated fatty acids that ower this cholesterol l,and their consumption is strongly linked to a reduced risk of cardiometabolic disease and overall mortality.
The reference intake of approximately 20% of the recommended daily energy intake is similar to that of a Mediterranean diet, which has been repeatedly associated with a reduced incidence of cardiovascular disease.
14, Added or free sugars (e.g., fruit juices)30 (0-30)≤ 5 % of total energy intakeAdded and free sugars provide no nutritional value and can be harmful if consumed in excess. Their consumption, particularly in the form of sugary drinks, has adverse cardiometabolic effects and has been positively associated with obesity, type 2 diabetes, coronary heart disease, and overall mortality.
The WHO recommends a maximum energy intake of free sugars corresponding to 5% of total calories.

Table 1. Components of the Planetary Health Diet. * The scale used to establish the adherence score to the diet varies across studies, with some using 10 points for each component (for a maximum of 140 points), while others use 1 point per component (for a maximum of 14 points). Adapted from Rockström et al. (2025) and Bui et al. (2024).

In general, our current eating habits do not correspond to these recommendations, and in most cases, even go in the opposite direction: we eat 7 times more red meat, 3 times more poultry and 2 times more dairy products than those suggested by the planetary diet, while the intake of vegetables, particularly whole grains, is well below the recommendations (Figure 2).

Figure 2. Differences between current diets and the Planetary Health Diet. The values ​​represent the comparison (in %) of the intake of each food category measured in North America in 2020 and those recommended by the Planetary Health Diet (dotted line). From Rockström et al. (2025).

Mutual benefits

The term “planetary diet” comes from data showing that its adoption would significantly reduce not only the risk of premature death, but also the greenhouse gas emissions associated with food production (Figure 3).

The planetary diet can therefore be considered a “win-win” eating pattern, beneficial for both human health and the environment.

Figure 3. Mutual benefits of the planetary diet on human health and the environment. Modelling the effects of greater population adherence to the planetary diet (reflected by an increase in the score) suggests that over a 20-year period, a halving of GHG emissions associated with food production would be correlated with a significant reduction in premature mortality. Adapted from Laine et al. (2021).

These benefits of the planetary diet have just been confirmed by a study showing that people who adhere most strongly to the diet see their risk of premature total mortality from cancer or from cardiovascular disease significantly reduced compared to those who adhere the least to these recommendations (Figure 3).

Figure 4. Association between planetary regime adherence scores and mortality risk. Data were collected from 42,947 participants in the US NHANES cohort conducted by the US Centers for Disease Control and Prevention (CDC). Adapted from Wang et al. (2025).

A meta-analysis of all studies that examined the impact of the planetary diet also shows a reduced risk of several specific diseases, including colorectal cancer (13% reduction), lung cancer (32%), coronary heart disease (17%), diabetes (26%), and stroke (16%). These results are consistent with the observation that the planetary diet is among those most closely associated with healthy aging, remaining free from major chronic diseases, and without impairment of cognitive, physical, or mental health (see our article on this topic).

In short, there are only benefits to increasing our intake of plant-based foods, both for our health and for the health of the planet.

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