To our knowledge, the present study is the first to assess total dietary intake in plant-based diets in Norway. This study provides a snapshot of the intake of meat and dairy substitutes among people adhering to different plant-based diets. In summary, most participants had consumed meat or dairy substitutes, and consumption was most frequent among vegans, followed by vegetarians and pescatarians. Vegans also had a higher contribution from the substitutes to total intake of total fat, saturated fatty acids, and protein. The participants had total macronutrient intake within NNR recommendations, presenting a favorable distribution of fatty acids in addition to high levels of dietary fiber.
While traditional plant-based diets have focused on whole foods, the modern adaptation of these diets may include highly processed alternatives for meat and dairy . Little is known about the impact of plant-based substitutes on diet quality and health, but recent studies suggest meat and dairy substitutes to be associated with higher intake of ultra-processed foods and less healthy eating patterns in plant-based diets [46, 47]. However, an analysis found meat substitutes to contain less total fat, saturated fat and more dietary fiber than their meat counterparts, although several products contained more sodium . Gibney raises the question of whether consumption of processed foods, such as meat and dairy substitutes matter, if the total nutrient intake remains within recommendations for optimal nutrient intake .
Consumption of plant-based meat and dairy substitutes
Plant-based meat and dairy substitutes are flooding the global market, and replacing regular meat or dairy with these products, rather than whole foods, have become increasingly common . These trends were reflected in the results presented in our study, as most participants reported to consume either meat or dairy substitutes during the last 24 hours. Previous studies have suggested that consumption of substitute products increase with increased avoidance of animal-source foods [14, 47, 49, 50]. Supporting this hypothesis, and coherent with all groups avoiding meat, the present study found no differences between groups in consumption of each product category of meat substitutes. Furthermore, our results showed the most prominent differences in consumption pattern of dairy substitutes, in milk and cheese categories. While, cow’s milk, and cheese, often consumed daily in the Norwegian diet, are included in vegetarian and pescatarian diets, vegans would need to replace these products with plant-based substitutes. Findings in this study suggest that plant-based substitutes for both meat and dairy may provide a convenient way of maintaining food habits, replacing the foods and beverages excluded in the different eating patterns.
Another potential explanation for the large proportion of vegans who reported use of substitutes, is that these products are considered good sources of protein (soy-based meat substitutes) or micronutrients (fortified dairy substitutes). As the main ingredient in the early meat substitutes, tofu and tempeh , soybeans have long been recognized as a source of high-quality protein in vegetarians diet [1, 50, 51]. In addition, soybeans have been recommended as a source of iron, potassium, zinc, and selenium in diets excluding meat [1, 50, 51]. More than 55% of the meat substitutes and 32% of the dairy substitutes reported in this study was based on soy, suggesting that soy-based products are frequently chosen. However, most dairy substitutes consumed were oat-based, probably due to the popularity and wide range of oat-based dairy substitute products by the Swedish brand “Oatly” , and the common use of oats in the Norwegian diet. Many variants of plant-based substitutes for milk on the Norwegian market have been fortified with calcium, vitamin B12 and vitamin D [52-55], and a recent report from the Norwegian National Nutrition Council, has recommended inclusion of calcium fortified plant-based substitutes for milk from soy as an alternative to cow’s milk . As most participants in the present study had followed their current diet for several years, they were likely well informed about how to compose a nutritionally adequate diet and may consequently have included substitute products to ensure intake of certain nutrients. Although, soy or oats were the preferred raw ingredients in most dairy substitute categories, 80% of the plant-based cheese substitutes were based on modified starches. Consistent with this observation, a recent study on nutritional composition and quality of plant-based cheese found most products to be based on a combination of refined coconut oil and starches with refined coconut nut oil being the main ingredient .
All groups reported total macronutrient intake within Nordic Nutrition Recommendations 2012 , and contrasts in macronutrient intake were usually strongest between vegans and pescatarians, with the exception of dietary fibers and added sugar. Similar to or results, other studies have found that vegans have a more favorable distribution of macronutrients, with a lower contribution of SFA [57, 58] and a higher contribution of PUFA [13, 57] to total energy intake, compared to vegetarians and pescatarians. These findings were as expected, since SFA are mostly found in animal-based foods, such as whole fat dairy products. Vegans therefore have few natural sources of SFA in their diets. Moreover, vegan diets may include ample amounts of plant-based oils, nuts, seeds, and whole grains, which are good sources of PUFA [10, 14]. Replacing SFA for PUFA is associated with reduced risk of cardio vascular disease (CVD) [59, 60], and improved blood lipid profile , which may in part explain the proposed cardio-protective effect of plant-based diets . Pescatarians was the only group to meet the requirements of ≥1 E% n-3 fatty acids in the present study , which may most likely be explained by a regular consumption of fatty fish. However, low intake of n-3 fatty acids in vegans (0.7 E%) and vegetarians (0.5 E%) may most likely indicate that they do not include adequate amount of n-3 rich plant-based food sources (i.e., flax seeds and flax seed oil, chia seeds and walnuts) or supplements to meet their requirements.
An analysis of protein intake in the European Prospective Investigation into Cancer and Nutrition-Oxford study (EPIC-Oxford study), showed a rising gradient with lowest intakes in vegans, followed by vegetarians and highest in pescatarians . A similar gradient was also observed in the French NutriNet-Santé study, though, this study did not distinguish between vegetarians and pescatarians . Although, the median intake of protein in vegans (13 E%) and pescatarians (15 E%) in the present study was almost equal to findings in the EPIC-Oxford study, vegetarians in the present study reported protein intakes similar to the vegans, thereby deviating from the previously observed gradient .
Previous studies have found intake of dietary fiber to increase with dietary restriction, observing the highest levels in vegans compared to other diets [13, 14, 58, 63, 64]. Similarly, in the present study, vegans reported the highest intake of dietary fiber in g/MJ, whereas no difference was observed between vegetarians and pescatarians. However, the median intake of dietary fiber in all three groups (5.2 g/MJ, 3.8 g/MJ and 4.2 g/MJ) exceeded the estimated average intake in the general Norwegian population (2.3 g/MJ) . The high intake of dietary fiber reported among all groups included in the present study was likely a result of high consumption of whole grains, legumes, vegetables, fruits, nuts, and seeds. These food groups represent main components in all healthy plant-based diets , and are often consumed in large amounts by vegans, vegetarians and pescatarians compared to omnivores [14, 49, 58, 63]. Consuming diets high in dietary fiber has also been associated with lower body weight, reduced CVD risk, and lower risk of colon cancer [66, 67]. Thus, the high content of dietary fibers in plant-based diets is suggested as one of the potential explanations for the lower relative risk of certain non-communicable diseases observed in vegetarian and vegan populations .
Although, vegetarians in the present study reported higher intake of added sugar than the other two groups, the intake in all groups was within the recommendations of <10 E%, and below the estimated average intake in the general Norwegian population (11 E%) . A possible explanation for this low intake of added sugar, may be that the study participants are more conscious about their health and have more nutritional knowledge compared to the general population. However, underreporting attributed to social-desirability bias cannot be ruled out. Participants may have inadvertently or deliberately, neglected to mention intake of sugary foods in the 24h, or underestimated the amount eaten.
The salt intake reported in this study was considerably lower than the estimated average salt intake in the Norwegian population (10 g/day) . However, only vegans (6.0 g) and vegetarians (5.2 g) met the recommendations in NNR  of ≤6 g/day. Due to the adverse effect of sodium on blood pressure reduction in salt intake is one of the main national and global targets for the prevention of non-communicable diseases [69, 70]. The relatively low levels of salt intake reported in this study, concurs with several studies which have found vegans and vegetarians to consume lower levels of sodium than meat-eaters [14, 17, 63]. However, both the EPIC-Oxford study  and the Adventist Health study 2  found no difference in sodium intakes between meat-eaters, pescatarians, vegetarians and vegans.
Contribution to macronutrient and salt intake from plant-based meat and dairy substitutes
Among participants who reported to consume plant-based substitutes in our study, vegans reported the highest contribution of total fat, SFA and protein from substitute products. As our results showed no differences in total energy intake (kcal) or total fat intake (E%) between the groups, the higher contribution from substitutes to total fat in vegans than pescatarians may simply be explained by a higher consumption of these products among vegans than pescatarians. However, the nutrient content in plant-based substitutes have been found to vary greatly [30, 32, 36, 56, 71], and although not assessed in this study, it is possible that products frequently consumed by the vegans contained more fat than the products consumed by the pescatarians. The prominent difference in consumption of dairy substitutes found between the diet groups, may be one possible explanation for differences in contribution from substitutes to SFA intake. However, with the exception of coconut-based milks, milk substitutes tend to have a lower SFA content than cow’s milk [34, 71, 72]. Furthermore, few participants reported to have consumed milk substitutes based on coconut, making it unlikely that consumption of plant-based substitutes for milk could explain the difference in SFA intake between the diet groups. A more plausible explanation is that while vegetarians and pescatarians may include whole fat dairy containing significant amounts of SFA, vegans have few natural sources of SFA in their diets. Thus, SFA from substitutes was likely to account for a larger proportion of the total SFA intake in vegans than in vegetarians and pescatarians.
Similarly, the higher contribution to protein intake from substitutes in vegans (19%) than pescatarians (7%) may also be explained by the lower total protein intake observed in vegans compared to pescatarians in this study. However, Bradbury and coworkers (73) also found contribution from vegetarian protein alternatives (excluding legumes, nuts and seeds) and plant-based substitutes for milk to be higher in vegans than pescatarians, with intermediate values reported by vegetarians .
Although, intake of salt from substitutes did not differ between groups, the median contribution to the total salt intake was substantial in vegans (18%) and vegetarians (15%), and suggest a potential negative impact on salt intake from substitute products. This is further supported by the high 75th percentiles (41% and 34% respectively). Although, neither plant-based substitutes for milk or cheese have been found to contain high levels of sodium [56, 72], high sodium content is one of the main concerns regarding nutrient content of meat substitutes [30, 36].