While plant-based eating is not a new topic per se (see our previous blog post for more information on possible health benefits, concerns, and considerations of plant-based eating), the marketplace is now inundated with new plant-based alternatives to many animal-based foods. Consumers are no longer confined to tofu options, as they can now purchase chicken wings, tuna, fish filets, burgers, meatballs and other foods in plant-based versions. Brands like Impossible® and Beyond Meat® promote the idea that their products have the same taste and mouthfeel as animal products and serve as a healthier alternative. But are they really healthier? SHIFT Dietitians compare these products, examine the research, and provide recommendations below.
Protein quality: Animal vs. plant
The nutritional quality of protein is assessed by essential amino acid (EAA) content, protein digestibility, net protein utilization, and biological value. These factors are used to determine the PDCAAS (protein-digestibility amino acid score), which assesses the ability of any given protein to meet the body’s amino acid requirements. Animal proteins tend to have higher PDCAAS scores because they contain more EAAs and have greater digestibility than plant proteins (see table below). Plant proteins have lower scores (except soy protein) because their molecular structures make them more resistant to digestion and they do not contain all EAAs.
Comparing Protein Quality Scores in Animal and Plant Sources
Phytogenic options also contain more fiber and antinutritive factors that could lead to lower digestibility.1 As such, even if plant-based products contain the same amount of protein as animal foods, the body may not be able to digest and use amino acids as efficiently. In addition, it is important to look at overall nutrient composition rather than a single ingredient when evaluating a product.
Nutritional Analysis of Plant-Based Meat Alternatives vs Animal Products
Meat alternatives are intentionally formulated to provide protein content comparable to levels found in beef and poultry. The Impossible® products derive protein from soy, and Beyond Meat® from peas and mung beans.2 Some products contain added vitamins/minerals that are naturally found in animal proteins, such as zinc and vitamin B12. Meat alternatives tend to contain some fiber, yet their saturated fat content is often comparable to that found in beef due to added coconut oil.2 Much like other processed foods, meat alternatives also contain higher amounts of sodium. At present, there is limited information on the net effect of these factors on health outcomes.
The Current State of the Research on Animal and Plant-Based Proteins
What we currently know from research:
- Plant-based diets are associated with positive health outcomes. Long-term epidemiologic studies have shown that replacing red meat with nuts, legumes, and other whole plant-based foods is associated with lower risk of chronic diseases and mortality.3,4
- Red meat intake is associated with negative health outcomes, such as obesity, Type 2 Diabetes, heart disease, and some cancers.3
- Processed food intake is associated with weight gain, due to increased overall caloric intake.5
What is new in the research:
- Independent of saturated fat content, TMAO* in animal proteins could be a risk factor for negative health outcomes. A study from 2020 compared the health effects of red meat and plant-based alternatives (Beyond Meat®, 2 servings/day) over 16 weeks. The main outcome studied was TMAO concentration, a possible emerging risk factor for cardiovascular disease. The results showed that TMAO concentrations were lower when participants followed the plant-based eating prescription, which contained alternative meat products compared to following an animal-based diet.5 (N.B., this study contained only 36 participants and was partially funded by Beyond Meat®, indicating a possible conflict of interest).
*TMAO, or Trimethylamine N-oxide, is an emerging risk factor for cardiovascular disease. Two precursors to TMAO, L-carnitine and choline, are found in red meat. Early studies have shown associations between high levels of TMAO in the blood and increased inflammation. One study found that individuals with increased TMAO concentrations had 60% higher risk for adverse cardiovascular events.6
The bottom line:
At this time, there are no rigorously designed, independently funded research that confirms positive health outcomes associated with replacing animal products with plant-based alternatives. While associations between whole plant-based diets and positive health outcomes have strong evidence, we lack conclusive support to recommend the replacement of plant-based alternatives for animal products. While early studies of this growing food category seem promising, the dearth of research makes drawing conclusions difficult at this time.
What Does SHIFT Recommend?
Some individuals may choose plant-based products for a variety of reasons outside of perceived health benefit – ethical or environmental considerations, religious practices, and taste preferences, among others – nevertheless we recommend treating these plant-based meat alternatives (e.g., Impossible®, Beyond Meat®) similarly to red meat when making dietary choices—
- Be moderate (i.e., 1-2 times/week) in your consumption of high-saturated fat proteins, including both red meat and meat alternative products.
- If choosing to have red meat or a meat alternative product, aim for balance by pairing with a salad or other non-starchy vegetable. If looking to reduce refined carbohydrate intake, try replacing the bun with a lettuce wrap or eat it open-faced on a high-quality whole grain bread.
- For ideal animal-based protein options, choose lean chicken, turkey, seafood, eggs, or low-fat dairy in place of red meat or meat alternatives with high saturated fat.
- For ideal plant-based options, look for plant-based proteins that are whole foods and low in saturated (e.g., tofu, legumes, soy). For other minimally processed plant-based products, reach out to Tavierney or Lauren for recommendations.
Most people would likely benefit from replacing some red meat in their diet with plant foods. At the end of the day, enthusiasm around these alternatives should not distract from the larger, more important aim of establishing a healthy dietary pattern for yourself.
If you have questions or would like more information on this topic, reach out to Tavierney (Tavierney.firstname.lastname@example.org) or Lauren (email@example.com).
Lauren & Tavierney
SHIFT Registered Dietitians
- Ismail, B, et al. Protein demand: review of plant and animal proteins used in alternative protein product development and production. Animal Frontiers, 2020; 10(4):53-63.
- Gelsomin, E. Impossible and Beyond: How healthy are these meatless burgers? Harvard Health Blog, 2019. https://www.health.harvard.edu/blog/impossible-and-beyond-how-healthy-are-these-meatless-burgers-2019081517448.
- Ask the Expert: Popular plant-based meat alternatives. The Nutrition Source, 2019. https://www.hsph.harvard.edu/nutritionsource/2019/08/26/questions-plant-based-meat-alternatives/.
- Kim, H, et al. Plant‐Based Diets Are Associated With a Lower Risk of Incident Cardiovascular Disease, Cardiovascular Disease Mortality, and All‐Cause Mortality in a General Population of Middle‐Aged Adults. JAHA, 2019; 8(16).
- Crimarco, A, et al. A randomized crossover trial on the effect of plant-based compared with animal-based meat on trimethylamine-N-oxide and cardiovascular disease risk factors in generally healthy adults: Study With Appetizing Plantfood—Meat Eating Alternative Trial (SWAP-MEAT). The American Journal of Clinical Nutrition, 2020; 112(5):1188-1199.
- Heianza, Y, at al. Gut Microbiota Metabolites and Risk of Major Adverse Cardiovascular Disease Events and Death: A Systematic Review and Meta‐Analysis of Prospective Studies. JAHA, 2017; 8(16).