More than 40 percent of North Americans are trying to eat more plant-based foods because of the ever-accumulating evidence that eating processed meat and mammal meat may increase risk for heart attacks, cancers and diabetes. Today, two companies — Impossible Foods and Beyond Meat — dominate the market for plant-based burgers that taste like meat. A major concern is that these products have not been tested for long-term safety. Nobody has shown that these plant-based meat alternatives are harmful, but we have no good research yet, and action on potential harms can be incredibly slow. In 1993, many studies showed that trans fats (partially hydrogenated oils) increased risk for heart attacks, but it took 10 years for the U.S Food and Drug Administration just to require listing them on food labels, and 25 years to ban trans fats from our food supply.

The Impossible Burger company claims that they employed more than 100 scientists, engineers, and researchers to make a completely vegan burger that looks, smells, and tastes like meat. They had to add something that looks and tastes like blood, and they found it in the roots of soy plants: leghemoglobin, a substance which, like red blood cells, is full of iron. Since soy roots contain only small amounts of leghemoglobin, the researchers had to synthesize it by altering yeast and soy genes to make the iron-containing red-blood-cell-like chemical for use in their Impossible Burger. They also added soy protein, coconut oil, sunflower oil, methyl cellulose, modified food starch, vitamins and other components. Beyond Meat burgers are different from Impossible burgers in that their blood-like qualities come from beet juice, and their protein comes from peas, rice and mung beans. Both plant-based burgers have close to the same amounts of calories, fats, carbohydrates and sugars as regular hamburger from cows.

Are These Laboratory-Made Foods Healthful?
The good news is that each of these plant-based burgers contains three grams of beneficial fiber, compared to none in a hamburger.
Both the Impossible Burger and Beyond Meat contain:
• more salt than a regular hamburger
• less protein than a regular hamburger, but lack of dietary protein is not a significant problem for most North Americans
• more saturated fat from coconut oils than hamburgers have, but so far nobody has shown that the saturated fat in coconut oil is harmful

The leghemoglobin in Impossible Burgers contains heme iron, and higher levels of heme iron can increase body stores of iron that raise risk for diabetes (BMC Med, 2012;10(1):119). Ten percent of North Americans carry the gene for hemochromatosis, a disease characterized by high iron levels that deposit in, and can destroy, the beta cells in the pancreas to cause diabetes (Int J Appl Basic Med Res, 2018 Jan-Mar; 8(1): 57–60). See my article on Ernest Hemingway and Hemochromatosis. At this time there are no long-term studies to show whether leghemoglobin is safe or healthful.

These burgers and other new plant-based meat alternatives are highly processed foods, and eating a lot of processed components of plants (instead of whole plant parts such as vegetables, beans, whole grains, nuts or fruits) has been associated with obesity (Cell Metabolism, May 16, 2019). See Are Processed Foods Making Us Fatter and Ultra-Processed Foods

My Recommendations
I agree with Dr. Frank Hu, one of the most highly-respected researchers in the field and author of a recent editorial in JAMA, recommending that “it will be important to remain vigilant to ensure that these new products are beneficial to human health as well as the health of the planet, and to understand and consider any unintended consequences” (JAMA, 2019;322(16):1547-1548). Until we know more, I think eating these plant-based meat alternatives is fine, but make them just a small part of your diet that includes a wide variety of vegetables, beans, whole grains, nuts, fruits and other healthful foods.