Plant-based alternatives to animal-based foods are not a new phenomenon. Tofu, for example, has often been treated as an alternative to meat for centuries. In more recent decades, food companies have processed mixtures of soy and other legumes, grains, and a variety of plants into burgers, nuggets, sausages, and other meat-shaped products. These creations were often targeted towards a vegan or vegetarian demographic, and despite their appearance, were not necessarily intended to completely recreate the taste of their meat-based counterparts.
However, a new generation of plant-based meat alternatives is aiming to do just that. In a recent JAMA Viewpoint, Dr. Frank Hu, Chair of the Department of Nutrition, and co-authors including Gina McCarthy, Director of C-CHANGE at the Harvard Chan School of Public Health, discuss how popular products like Impossible Foods’ and Beyond Meat’s burger patties are aimed to appeal to a broader consumer base with their “unique mimicry” of beef in both taste and experience.  They also note how these products are often marketed as a way to “help reduce reliance on industrial meat production,” aligned with recent reports calling for dietary patterns higher in plant-based foods for both human and planetary health. [2,3]
Can these novel products be considered part of a healthy and sustainable diet? According to the Viewpoint authors, the answer to this question “remains far from clear given the lack of rigorously designed, independently funded studies.” We spoke with Dr. Hu to learn more about the potential benefits and concerns surrounding popular plant-based meat alternatives.
Although these alternative meats are being made from plants, you suggest caution in applying existing research findings on plant-based foods and human health. Can you talk about some of that evidence, and why it’s not readily applicable?
First of all, research has found that diets high in red meat, especially processed meat, have been associated with a range of health consequences, including obesity, type 2 diabetes, cardiovascular disease, and some cancers. At the same time, long-term epidemiologic studies have shown that replacing red meat with nuts, legumes (e.g. lentils, peas, soy, beans), and other plant-based protein foods is associated with lower risks of these chronic diseases and total mortality.  Randomized clinical trials have also demonstrated that this replacement reduces levels of total and LDL cholesterol. 
However, rather than incorporating plant foods like legumes, these products are generally relying on purified plant protein. They are also highly processed. Food processing may not only lead to the loss of some nutrients and phytochemicals naturally present in minimally processed plant foods; it can also create highly-palatable products. Although short-term, a recent controlled feeding study found that diets high in ultra-processed food cause excess caloric intake and weight gain.  Therefore, we can’t directly extrapolate existing findings on plant-based foods and dietary patterns to these novel products.
Let’s focus on the two products currently dominating the landscape of alternative meats. Given that they’re often being consumed in the form of a burger, what specific questions are raised from a human health perspective?
Although Beyond Meat and Impossible burger patties contain zero cholesterol, are lower in total and saturated fat than a beef burger patty, and similar in protein and calories as a beef burger patty, they are both higher in sodium. As we note in the Viewpoint, there is no existing evidence to substantiate whether these nutrient differences alone offer any significant health benefit as a replacement.
People also aren’t typically eating burger patties on their own, so we also have to think about the broader context in which they’re consumed. For example, when placed between a bun made of refined grains, covered in sauces and other toppings, and accompanied by French fries and soda, we can’t assume that substituting one of these alternative patties for a burger patty will improve overall dietary quality.
These products achieve their imitation of meat through different processing technologies. Can you briefly explain how they differ, and if there are any unique concerns related to the methods used?
In a beef burger, the inherently “meaty” flavor is derived from an iron-containing molecule called heme. Impossible Foods actually takes heme from the roots of soy plants and ferments it in genetically engineered yeast. The high amounts of heme that end up in the burger give a meaty flavor and appearance. One potential concern that has been raised is that higher intake of heme iron has been associated with increased body iron stores and elevated risk of developing type 2 diabetes. 
Beyond Meat does not use heme, but rather a processing method that (according to information from the company) “aligns plant-proteins in the same fibrous structures you’d find in animal proteins,” and then combines fats and minerals that mimics the composition and flavors of meat. Pomegranate powder and beet juice impart a “bloody” red color.
What do you propose as a way forward in researching these novel meat alternatives?
Since these are so new and rapidly developing, it won’t be feasible to conduct large, long-term trials on disease outcomes. However, short-term, independently-funded intervention trials can be conducted to compare the effects of these products—both with their animal-based counterparts as well as minimally-processed plant protein sources—on cardiometabolic risk factors and other factors including the microbiome. Intervention and observational studies can also examine how these plant-based meat alternatives influence overall diet quality, caloric intake, nutrient status, and body weight. Zooming-out, we’ll also need to look at whether an increase in these alternatives actually leads to reduced red meat intake.
Of course, any research on this topic will not be without its challenges. With technological innovations and product reformulations, the products on the market may change quickly in both composition and availability. Red meat replacements are most popular now, but others being introduced or developed may include fish and poultry. Beyond plant-based meats, another product suite on the horizon is lab-grown meats, where animal cells are cultured to provide the product without raising and slaughtering the animal.
What are some other implications of these technologies that should be considered in researching and discussing this topic?
The goal of these technologies is to disrupt the status quo of conventional animal agriculture, which can have important public health, regulatory, and environmental implications. Regarding our planet’s health, these technologies could represent a significant opportunity to reduce greenhouse gases that fuel climate change, as well as other concerns related to existing industrial animal-based food production. For example, a Beyond Meat-commissioned Life Cycle Assessment found that the Beyond Burger generates 90% less greenhouse gas emissions, requires 46% less energy, 99% less water, and 93% less land use than a burger made from U.S. beef.  To be clear, such findings warrant further independently-funded studies. We should also remember to consider these products as compared with the production of minimally processed plant-based foods.
When examining these shiny new technologies, what are some key points we should not lose sight of?
As the global demand for meat is projected to increase in coming decades, these technologies may have a role to play. However, they are far from the only answer to calls for shifting to more plant-based dietary patterns. Enthusiasm around plant-based meats and other alternatives should not distract from the bigger picture that a healthy dietary pattern includes an abundant amount of minimally processed plant foods—vegetables, fruits, whole grains, legumes, and nuts; moderate amounts of dairy products, seafood, and poultry; and lower amounts of processed and red meat, sugar-sweetened foods and beverages, and refined grains.
Paraphrasing our Viewpoint conclusion, a fundamental change in the food system requires policies and actions that create a culture in which healthy and sustainable food choices are accessible, affordable, enjoyable, and the norm. Technology will certainly play a role, but we need to keep an eye on new innovations to ensure they are beneficial to both human and planetary health, and consider any unintended consequences.
- Hu FB, Otis BO, McCarthy G. Can Plant-Based Meat Alternatives Be Part of a Healthy and Sustainable Diet? JAMA. Published online August 26, 2019.
- Willett W, Rockström J, Loken B, Springmann M, Lang T, Vermeulen S, Garnett T, Tilman D, DeClerck F, Wood A, Jonell M. Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems. The Lancet. 2019 Feb 2;393(10170):447-92.
- The Intergovernmental Panel on Climate Change. Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. https://www.ipcc.ch/report/srccl/.
- Zheng Y, Li Y, Satija A, Pan A, Sotos-Prieto M, Rimm E, Willett WC, Hu FB. Association of changes in red meat consumption with total and cause specific mortality among US women and men: two prospective cohort studies. BMJ. 2019 Jun 12;365:l2110.
- Guasch-Ferré M, Satija A, Blondin SA, Janiszewski M, Emlen E, O’Connor LE, Campbell WW, Hu FB, Willett WC, Stampfer MJ. Meta-analysis of randomized controlled trials of red meat consumption in comparison with various comparison diets on cardiovascular risk factors. Circulation. 2019 Apr 9;139(15):1828-45.
- Hall KD, Ayuketah A, Brychta R, Cai H, Cassimatis T, Chen KY, Chung ST, Costa E, Courville A, Darcey V, Fletcher LA. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell metabolism. 2019 May 16.
- Bao W, Rong Y, Rong S, Liu L. Dietary iron intake, body iron stores, and the risk of type 2 diabetes: a systematic review and meta-analysis. BMC medicine. 2012 Dec;10(1):119.
- Heller MC, Keoleian GA; Center for Sustainable Systems, University of Michigan. Beyond Meat’s Beyond Burger Life Cycle Assessment: a detailed comparison between a plant-based and an animal-based protein source. Published September 14, 2018.