Plant-based diets: a review of the definitions and nutritional role in the adult diet Proceedings of the Nutrition Society

Hereafter, all variations of PB diets within these studies will be referred to collectively as PB diets and all comparative/baseline diets will be described as omnivorous. Tables 3–5 present the energy, macronutrients, dietary fibre and micronutrient intake data from these studies. All values are reported as mean intakes with the exception of one study, which reported medians, as outlined in the respective tables.

Q: Does eating only plant-based foods result in weight loss?

Where energy in MJ and percentage energy (%E) of nutrients were not provided, this was calculated using standardised conversion factors for easier comparison between studies(77). Micronutrient intakes are reported from the food component of the diet only (i.e. intakes from nutritional supplements are not included). Where retinol was presented as international units (IU), this was converted using standardised conversions for easier comparison between studies(78). Finally, the authors of a 2014 study carefully dissected the umbrella term “plant-based diet” and discussed the different dietary patterns used in their study. The study included a vegan diet (excluding all animal products), a vegetarian diet unimeal-review.com/trustpilot/ (excluding meat and seafood), a pesco-vegetarian diet, a semi-vegetarian diet and an omnivorous diet [31]. This study was not considered in the final dietary group assignment.

The focus should be on eating more of the right plants, avoiding the wrong kind, eliminating unhealthy foods, and moderating your intake of healthier animal products. Vegan diets are entirely plant based, excluding all animal-derived products and ingredients. Animal foods are one of the primary sources of vitamin B-12; therefore, vegans should include B-12–fortified foods such as cereals, nutritional yeast, and some plant-based beverages and take a B-12 supplement to ensure adequate intake. “The goal is to increase the amount of nutrients, fiber and antioxidants you’re getting by eating more whole, plant-based foods, but the diet doesn’t eliminate fish, chicken, eggs or dairy products,” says Snyder. “I think that’s the appeal of this eating pattern. It offers more flexibility than a vegetarian or vegan diet, which many people find hard to maintain.”

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Plant sources include whole grains, soy products, lentils, beans, nuts and wheat germ. Research on zinc in the diet has found that it supports the immune system and vision, specifically. Omega-3 fatty acids are found in fish, canola oil, soy oil, walnuts, ground flaxseed and soybeans. Vegetarian diets that do not include fish may be low in two types of omega-3 fatty acids called DHA and EPA.

The benefits of a plant-based diet

While studies considered in this review found that iron intake from both PB and omnivorous diets met recommendations from the UK DOH and the NNR, it is important to acknowledge the bioavailability of haem iron compared to non-haem iron. The US Institute of Medicine recommends an iron intake 1⋅8 times higher for vegetarians than that of omnivores due to the lower bioavailability of non-haem iron arising from PB foods compared with the haem iron from animal-derived sources(Reference Sobiecki, Appleby and Bradbury45,Reference Trumbo, Yates and Schlicker95) . While lower ferritin levels have been reported in those consuming PB diets compared to omnivorous diets, a recent systematic review found that there is no difference in the prevalence of iron deficiency between those following a PB diet and those following an omnivorous diet(Reference Bakaloudi, Halloran and Rippin25).

How to get enough protein

• In case of any doubts, we contacted the authors of the respective publications via email to confirm that the sample was the same.
• Some people use vegan protein supplements, usually made from legumes, such as soy and peas.
• While the majority of trials prescribed a technically vegan diet, 20% of trials included a semi-vegetarian eating pattern.
• By taking animals out of the equation, plant-based meat also significantly lowers the risk of future pandemics.
• Table 1 outlines the PB diet definitions identified in this review.
• Plant-based eating plans can work for everyone, and individuals have the choice of what they want to include or exclude.

Excess energy contributes to disease epidemics, including cardiovascular diseases, metabolic diseases including diabetes, many cancers, and decreased quality of life. Whole food, plant-based diets address these problems of nutrition adequacy and excess by providing all nutrients necessary (with the possible exception of vitamins B12 and D) without excess calories and foods that promote increased risk for chronic disease. “Sometimes it’s easier to get nutrients like protein and calcium from animal-based products, but we should still do that in a healthy way,” recommends Snyder. “By choosing chicken and fish instead of beef, for instance. And we can eliminate the saturated fat from dairy products completely by having skim milk and 0% Greek yogurt.”

Are plant-based diets healthy? A nutritionist’s view…

Plant-based diets also tend to be lower in unhealthy saturated fat and cholesterol. Vegetarians don’t eat the flesh of animals, such as meat, poultry, and fish, but they often eat dairy and eggs. This even includes foods that are produced by animals, such as honey. Some people choose to take healthy eating one step further and eliminate animal proteins, dairy products, processed foods and limit oils in their daily meal plan. However, change in food production and food systems, rapid urbanization and changing lifestyles have led to a shift in dietary patterns. People are now consuming more highly processed foods high in unhealthy fats, free sugars and salt/sodium, and many people do not eat enough fruit and vegetables or consume sufficient dietary fibre.

The nutritional role of plant-based diets

The intention behind this process was to gain a better understanding of the concept of “plant-based diet” and to examine how the term is used in scientific studies. Figure 1 includes descriptions of the pre-defined dietary groups. Chronic diseases are increasing in global prevalence and a leading cause of mortality in the world [1, 2]. Heart disease, metabolic syndrome, and type-2-diabetes are unimeal trustpilot driven by unhealthy consumption patterns, including refined sugars, processed meats, and high-fat foods [3].

With regard to dietary sugars, those consuming PB diets had a similar or higher intake (22–27 %E) of total sugar compared to omnivorous diets (20–23 %E)(Reference Allès, Baudry and Mejean44,Reference Sobiecki, Appleby and Bradbury45,Reference Clarys, Deliens and Huybrechts47) . No study reported free sugar intake and only Kristensen et al.(Reference Kristensen, Madsen and Hansen79) provided an estimate of added sugar intake, where intake of added sugars in the PB diet was lower (3–4 %E) than the omnivorous diet (8 %E) (data not shown). However, the omnivorous diet in this study may not be representative of a typical adult diet in the Western world where intakes of added sugars are typically about 10 %E(Reference Walton, Bell and Re87). These findings may be expected due to the high dietary fibre content of PB foods such as fruits, vegetables, legumes and wholegrains, compared to animal-derived products. Table 1 outlines the PB diet definitions identified in this review.

Types of vegetarian diets

You can either take a daily supplement or eat plenty of plant-based foods with higher levels of the nutrients you’re targeting. A plant-based diet means eating lots of fruits, vegetables, and whole grains. From there, the types of proteins and fats you eat can vary according to your preferences. If followed properly, a whole foods, plant-based diet limits the use of oils, added sugars and processed foods, leaving only whole foods to provide nutrition.

Top 10 Foods to Eat

And the quality of the food you’re eating matters, no matter what type of eating pattern you follow. A 2021 Journal of Nutrition study found that the more people avoided meat, the more ultra-processed foods they ate; the authors concluded that not all vegetarian diets automatically have health benefits, and that highly processed foods can affect the nutritional quality of the diet. To others, a plant-based diet means eating mostly plants, while occasionally enjoying meat, fish, eggs and dairy. The basic tenets, however—eating more whole plant foods (like whole grains, fruit, vegetables, legumes, nuts and seeds) and reducing intake of animal products—are the same.

Healthy Eating Patterns

Healthy eating, which promotes weight management and good nutrition, includes a variety of food groups that are chock full of vitamins, fiber, and minerals. Strive for diversity in your meals, and include fiber-rich foods that capture all the colors of the nutrition rainbow. “I recommend eating limited amounts of these processed plant-based options since the manufacturing of these meat alternatives tends to require a lot of additives and ingredients that aren’t necessarily healthy, like excess salt and saturated fats,” warns Snyder. It’s why dietitians like Snyder prefer plant-based eating patterns.

On the other hand, plant-based protein sources tend to cost significantly less than meat or fish protein. Some protein sources, like nuts and seeds, are calorie dense, meaning they provide a high number of calories in small portions due to their higher fat content. To assist in planning meals, the table above provides the amount of protein in some plant-based foods. “The main downside of meat and animal products is the saturated fat content, in terms of how it can raise cholesterol and potentially be inflammatory,” says Snyder.

Universal Meals makes it easy to offer delicious recipes that work for almost every type of diet. MAS was responsible for designing the review protocol, writing the protocol and report, conducting the search, screening potentially eligible studies, extracting and analyzing data, interpreting results and drafting the manuscript. These findings may have important scientific and clinical implications. Clear definitions of a term or concept are necessary to allow for scientifically sound and reproducible results.