Increasing Plant-Based Meat Alternatives and Decreasing Red and Processed Meat in the Diet Differentially Affect the Diet Quality and Nutrient Intakes of Canadians

As a macronutrient, protein is an indispensable component of the human diet and serves important physiological roles, including immune and endocrine function, metabolism, and muscle and bone growth [1]. According to the most recent Dietary Guidelines for Americans (2015–2020), the Recommended Dietary Allowance (RDA) for protein intake in adults is 0.8 g/kg of body weight, which is 56 g/day for a 70 kg individual or about 10% of energy intake [2]. Dietary protein may be derived from animal sources, plant sources, or a combination of both. Approximately two-thirds of protein intake in Western countries originates from animal sources, and the remaining one-third comes from plant sources [3]. Meat (i.e., red meat, poultry, game, processed meat, and offal) is the major source of animal protein intake (38%), and grains are the most important contributing food group for plant protein intake (17%) in Western countries [3]. Although animal sources of protein are of higher quality, a growing body of evidence suggests that diets high in red and processed meat are associated with negative environmental impacts and poorer health outcomes [4,5,6,7,8]. In a population-based cohort study with 16 years of follow-up, Etemadi and colleagues found an association between high intakes of red and processed meat and elevated all-cause mortality and mortality from most major causes: cancer, diabetes, cardiovascular disease, kidney disease, liver disease, and respiratory diseases [4]. In a prospective cohort study with 32 years of follow-up, protein intakes from animal and plant sources were assessed in relation to all-cause and cause-specific mortality among over 131,000 men and women. The authors reported that replacing protein from animal sources, especially processed red meat, with plant-based protein sources was associated with substantially reduced overall mortality [9]. On the basis of these observations and the positive health effects of the regular intake of plant-based foods on human health, the new Canada’s Food Guide (2019) has merged the former “meat and alternatives” and “milk and alternatives” food groups into one group, known as “protein foods.” This version of Canada’s Food Guide has also placed a major emphasis on plant-based sources of protein [10]. The recently released EAT-Lancet Commission report (2019) also showed that the transformation to healthy diets by 2050 will require substantial dietary shifts. This includes more than doubling the consumption of healthy foods such as legumes, nuts, fruits, and vegetables, and a greater than 50% reduction in the consumption of less healthy foods such as red meat and added sugars [11]. According to the EAT-Lancet report, a diet rich in plant-based foods and with fewer animal source foods not only improves human health, but also confers environmental benefits [11]. In this regard, Westhoek et al. reported that replacing 25–50% of animal-derived foods with plant-based foods on a dietary energy basis in the European Union would result in a 40% reduction in the intake of saturated fat, a 25–40% reduction in greenhouse gas emissions, a 40% reduction in nitrogen emissions, and 23% per capita less use of cropland for food production [12]. This is the first study to examine the impact of doubling the consumption of plant-based meat alternatives and reducing the consumption of red and processed meat by 50% on the nutrient intake of Canadians.

The primary objective of the present study was to use national survey data to model a dietary scenario to assess the potential effects of increasing the intake of plant-based meat alternatives and decreasing the consumption of red and processed meat on the diet quality and nutrient intakes of Canadians. To accomplish this goal, we conducted a diet modeling exercise to increase the amount of currently consumed plant-based meat alternatives (i.e., legumes, seeds, and nuts) by 100% while decreasing red and processed meat consumption by half. We also aimed to (1) determine the percent contribution of red and processed meat to daily energy and nutrient intake among red and processed meat consumers, and (2) determine the percent contribution of plant-based meat alternatives to daily energy and nutrient intake among plant-based meat alternatives consumers.

In the present study, we aimed to model a dietary scenario to assess the potential impact of increasing the currently consumed plant-based meat alternatives (by 100%) and decreasing the currently consumed red and processed meat (by 50%) on the diet quality and nutrient intakes of Canadians. This dietary scenario resulted in a significant increase in the dietary intakes of fibre, PUFA, magnesium, and DFE, and was accompanied by a significant decrease in protein, cholesterol, zinc, and vitamin B12 intake. Further, based on the NRF scores, the overall nutritional value of the simulated diet was higher than the baseline diet.

Animal-based protein sources such as red meat generally contribute more protein than plant-based protein foods do [22]. Although nuts and certain types of beans (black and great northern beans) are comparable in their protein content to meat, vegetable products, certain types of beans (lima beans, pinto beans, and kidney beans), and soy-based tofu products have much lower protein contents [22]. Our results revealed that doubling the intake of plant-based meat alternatives and reducing the intake of red and processed meat by half resulted in a significant decrease in protein intake (−4.4 g/day). Using biophysical models and methods, Westhoek et al. examined the consequences of replacing 50% of animal-derived foods with plant-based foods on a dietary energy basis in the European Union [12]. In this regard, the authors developed three alternative diets by a 50% reduction in the consumption of beef, pig meat, poultry, dairy, and eggs, which was compensated by an increase in cereals. Their results showed that the protein intake in the alternative diets was up to about 10% lower than the protein intake in the reference diet. However, even with a 50% reduction in all animal products, the mean protein intake in the European Union was still 50% higher than the dietary protein requirements [12]. Using baseline data from the PREMIER clinical trial (1999–2002), Lin et al. reported that animal-based proteins and plant-sourced protein foods comprised approximately 66% and 34% of the daily protein intake, respectively, among U.S. adults. However, age, sex, body weight status, and race significantly influenced the contribution patterns from different food groups [23]. Using dietary intake data from the National Health and Nutrition Examination Survey (NHANES) 2007–2010, it was found that poultry and meats, respectively, accounted for 10% and 9.5% of daily protein intake, while plant-based foods contributed to only 3.2% of daily protein intake in American men and women aged >19 years [24]. Cifelli et al. used national survey data from the NHANES 2007–2010 to assess the effects of increasing dairy foods or plant-based foods on the macronutrient intake and nutrient adequacy of U.S. children (2–18 years) and adults (≥19 years) [25]. The authors compared the usual diet at baseline with three dietary scenarios that increased intakes by 100%: (1) plant-based foods, (2) protein-rich plant foods (i.e., soy, nuts, seeds, legumes), and (3) dairy (i.e., milk, cheese, yogurt). In the first two scenarios, there was a commensurate decrease in animal products intake. Increasing the intake of plant foods by 100% resulted in a significant decrease in protein intake in both children (from 68.7 to 58.0 g/day) and adults (from 82.1 to 64.9 g/day). In contrast, doubling protein-rich plant-based foods did not impact any of the nutrients because they were consumed in very low quantities in the baseline diet [25]. Using the same national survey data, it was found that doubling the intake of plant-based foods (as currently consumed) and commensurate reductions in animal-based protein intake resulted in an about 22% decrease in protein intake per ideal body weight in males and females aged ≥51 years [26]. Although plant-based meat alternatives provide a lower quantity of protein than animal products do, the amounts of protein in plant-based (lacto-ovo-vegetarian diets with half of all protein from plant sources) or vegan food patterns are above the RDA [27]. Therefore, replacing animal-based proteins with plant-based meat alternatives would not result in a protein deficit.

Plant-based, protein-rich foods like legumes, nuts, and seeds are low in saturated fat content, free of trans fat, and cholesterol-free [28]. Although, compared to meat, nuts usually have an intermediate amount of saturated fat content (3.8–7.8 g/100 g serving), soy-based tofu products (0.5–0.8 g/100 g serving), beans (0.1–0.7/100 g serving), and vegetable products (less than 0.1/100 g serving) are very low in saturated fat content [22]. Our results showed that plant-based meat alternatives accounted for only 13% of saturated fat intake in plant-based alternatives consumers, while red and processed meat contributed to 21.2% of saturated fat intake in red and processed meat consumers. Further, when currently consumed plant-based meat alternatives were increased by 100% and red and processed meat were decreased by half, there was a significant decrease in the cholesterol intake (−22.8 mg/day) and a non-significant decrease in the saturated fat intake (−0.7 g/day). Westhoek et al. reported that replacing 50% of animal-derived foods (i.e., beef, pig meat, poultry, eggs, and dairy) with plant-based foods (i.e., cereals) on a dietary energy basis would result in a 40% reduction in the intake of saturated fat in the European Union, where the per capita intake of animal foods is high [12]. Using data from children, adolescents, and adults participating in the What We Eat in America (WWEIA) 2003–2004 and NHANES 2005–2006, Huth et al. found that cheese (16.5%), beef (8.5%), and milk (8.3%) are the three top sources of saturated fatty acids in the U.S. diet [29]. Using national survey data from the NHANES 2007–2010, it was found that increasing the amount of currently consumed plant-based foods by 100% and decreasing animal products on a gram per gram basis resulted in a significant decrease in saturated fat intake in both U.S. children (from 25.2 g/day at baseline to 20.1 g/day) and adults (from 26.2 g/day at baseline to 20.0 g/day) [25]. However, increasing protein-rich plant-based foods by 100% and a commensurate decrease in animal products had only a negligible effect on the saturated fat intake in both children and adults [25]. The same results were obtained in another study conducted in female adolescents aged 9–18 years, in which a similar approach was used [30]. During a 6-month randomized controlled trial, overweight and obese adults on a vegan diet had a significantly lower percentage of energy from saturated fat (2 and 6 months) and a lower intake of cholesterol (2 and 6 months) when compared with those on a vegetarian, semivegetarian, pescovegetarian, or omnivorous diet [31]. Since the majority of Canadians consume more than the recommended 10% of total energy intake from saturated fat [32], replacing animal-based proteins, especially red and processed meat, with plant-based meat alternatives could be an effective strategy in reducing saturated fat intake.

Unlike plant-based meat alternatives, which are rich sources of carbohydrates such as fibre, starch, and oligosaccharides, meat is very low in carbohydrates and contains no dietary fibre [22,33]. Our results revealed that increasing the currently consumed plant-based meat alternatives by 100% and decreasing red and processed meat by half resulted in a significant increase in dietary fibre intake (+1.3 g/day) among the Canadian population. Cifelli et al. showed that doubling the currently consumed plant-based foods in the American diet significantly raised dietary fibre intake in children (from 13.5 g/day at baseline to 18.2 g/day) and adults (from 16.4 g/day at baseline to 21.6 g/day) [25]. In this dietary scenario, the percentage of children and adults with dietary fibre intakes above the adequate intake (AI) increased 5.1 and 2.6 times, respectively, compared to the baseline. However, no significant difference was observed in the dietary fibre intake between the usual diet and the dietary scenario that increased protein-rich plant foods by 100% [25]. Using the same national survey data, Demmer et al. also reported that doubling the amount of currently consumed plant-based foods increased the intake of dietary fibre by about 4 g/day among adolescent females [30]. However, the impact of doubling protein-rich plant foods on dietary fibre intake was negligible, since they were consumed in very low quantities at the baseline [30]. Moreover, in a 6-month randomized controlled trial, overweight and obese adults on a vegan diet had significantly greater intakes of dietary fibre (31.0 g/day), compared with participants on a vegetarian (26.7 g/day), pescovegetarian (21.0 g/day), semivegetarian (17.6 g/day), or omnivorous diet (17.6 g/day) at 2 months [31]. Furthermore, most Canadian men and women consume only about half of the recommended daily intake of dietary fibre (25 g/day for women and 38 g/day for men) [34]. Therefore, increasing the intake of plant-based meat alternatives could assist in increasing dietary fibre intake in the Canadian population.

Meat and meat products are valuable sources of some micronutrients, especially zinc, iron, and vitamin B12, which are known to be nutrients of concern in the diet of vegetarians [35,36]. In our dietary scenario, the partial replacement of red and processed meat with plant-based meat alternatives resulted in a significant decrease in the dietary intake of zinc (−0.9 mg/day) and vitamin B12 (−0.59 mcg/day), but had no impact on iron intake. In a study conducted in representative population samples of U.S. adults of five ethnic/racial groups, the contribution of meat was found to be substantial for vitamin B12 (19.7–40%) and zinc (11.1–29.3%) and, to a lesser extent, for iron (4.3–14.2%) [37]. In a cross-sectional study of female university students, Fayet et al. found that the avoidance of animal foods adversely affected the intakes of zinc, bioavailable iron, selenium, vitamin B12, and omega-3 fatty acids [38]. Doubling the intakes of plant-based foods with commensurate decreases in animal products was accompanied by increases in iron and folate intakes and decreases in zinc, calcium, and vitamin D intakes among female adolescents [30]. The same dietary scenario resulted in significant decreases in calcium and vitamin D intakes and significant increases in iron, magnesium, and folate intakes among U.S. children and adults. However, similar to our findings, increasing protein-rich plant foods by 100% had no significant impact on the dietary intake of iron [25]. In a 6-month randomized controlled trial, overweight and obese adults on an omnivorous diet had a significantly higher zinc intake than the participants on a vegan, vegetarian, pescovegetarian, or semivegetarian diet at both 2 and 6 months. There was no significant difference in iron intake at any time point between the adults following different dietary interventions [31]. It should be noted that, although plant-based meat alternatives, especially beans and nuts, are high in iron content [22], the form of this iron is non-heme, which is less bioavailable than heme iron [39]. Further, increasing the intake of phytate-containing legumes may compromise the absorption of both non-heme iron and zinc [40]. Therefore, when replacing red and processed meat with plant-based meat alternatives, caution should be taken to avoid potential zinc, vitamin B12, and iron deficiencies.

In conclusion, the results of this modeling study revealed that the partial replacement of red and processed meat with plant-based meat alternatives could lead to the improvement in dietary intake of some nutrients such as dietary fibre, magnesium, folate, and PUFA. Such a dietary scenario could limit the intake of cholesterol among the Canadian population but would have only minor effects on the saturated fat and sodium intake. Moreover, this dietary scenario would enhance the overall nutritional value of the diet, as reflected by higher NRF scores. On the other hand, doubling the intake of plant-based meat alternatives and decreasing red and processed meat by half would result in a significant decrease in the dietary intake of protein, zinc, and vitamin B12. According to the literature, Western dietary patterns contain an excess of protein, and subtracting meat from current Western diets or replacing meat with plant-based alternatives would not result in a protein deficit [41]. When replacing red and processed meat with plant-based meat alternatives, caution should be taken to decrease the risk of deficiencies for specific micronutrients, especially zinc and vitamin B12. Furthermore, this study adds to the literature on the sociodemographic differences of red and processed meat and plant-based alternatives consumers and non-consumers, which could be used by policy makers to develop targeted strategies to increase the intake of plant-based sources of protein.