Today – we look at some of the best research on plant-based meat. And we start with the SWAP meat study – that puts “beyond meat” products to the test.
As the chair of Harvard’s Nutrition department put it, transitioning global diets towards healthy plant-based dietary patterns would require large-scale public health efforts, but could be instrumental in ensuring future human health.
In my book How Not to Diet, in the chapter on habit formation, I talk about how you can change your existing bad habits to good ones––or establish new good habits from scratch––using a technique known as implementation intentions. Instead of vague self-promises to “do our best,” implementation intentions are specific if-then plans to perform a particular behavior in a specific context. They take the form of “When situation X arises, I will perform response Y.” For example, If I get hungry after dinner, I will eat an apple. If the triggering circumstance is a regular, daily occurrence, implementation intentions can be the beginning of a beautiful habit.
So, what about using implementation intentions to cut down on meat? After all, most food choices are just due to ingrained habits, and meat is no exception. Here, they were trying to get people to change from a climate perspective, noting more greenhouse gas emissions from animal ag than all cars, trucks, trains, ships, and planes combined. But whatever the reason, researchers randomized people to form “if–then plans” (for example, “If I visit the university cafeteria for lunch tomorrow, then I will choose one of the vegetarian meals”). Motivating people to consciously form an implementation intention, specifically how to implement a goal seems to be such a simple technique, but it works. Forming an implementation intention led people not only to think more often about their intention to reduce meat consumption, but also to eat less meat, despite the strong force of habit. On one hand, breaking a habit may be one of the most challenging tasks we set ourselves. On the other hand, a first, yet effective, step in getting there seems to be writing down the goal of change in the form of an if-then statement on a piece of paper. Even a journey of a thousand miles begins with a single step.
How else can we transition to reduced-meat diets? We talked about making the healthier option the default option. We could also minimize disruption, by producing affordable, recognizable, and tasty plant-based meat alternatives. The topic of plant-based meat alternatives (PBMAs) has been discussed for several decades, but it has only recently become one of the hottest topics in the food and research communities. After all, one of the largest perceived barriers for switching diets was the enjoyment of eating meat. And so, if you can deliver a similar taste and mouthfeel, it could help people shift. And, it seems like it’s working. In recent years in North America, plant-meat sales grew by 37 percent.
The company that makes the Beyond Burger decided to put up or shut up by funding a study through Chris Gardner’s prestigious lab at Stanford. A randomized crossover trial to compare the effect of consuming plant-based alternative meat to animal meat on human health by having people eat at least two servings a day of plant versus animal meat for eight weeks each, while keeping everything else as similar as possible. So, instead of burgers and beef from cows, sausage from pigs, and breasts from chickens, they ate burgers, sausage, and chicken made from plants. Now, if they were trying to game it to give Beyond Meat an advantage, they’d have chosen the worst possible meats to compare it to. But no, the meat was organic, grass-fed to give the fairest comparison possible.
So, what happened? Significant drop in TMAO levels during the plant-based meat phase. That’s a good thing, as I’ve explored before. The consumption of meat, dairy, and eggs can be turned by bad gut bacteria into trimethylamine, which is oxidized by our liver into TMAO, which is associated with heart failure, kidney failure, and our number one killer, atherosclerosis, the hardening of our arteries.
The plant-based meat group also achieved a significant drop in cholesterol. No surprise, given the lower saturated fat intake. Of course, if they had been eating whole plant foods instead, like beans, saturated fat would have been way down, fiber way up, and sodium way down. In fact, there was basically no difference in sodium intake. So, no surprise, no difference in blood pressure.
The big surprise was weight. During the plant-based meat phase, they inadvertently lost a couple pounds. Some of the plant-based meats are highly processed, and normally you’d expect people to gain weight. However, weight was modestly but statistically significantly lower after eight weeks on the plant rather than on the animal phase. Notably, this was observed despite no differences in reported total calorie intake or physical activity levels between each phase. Same calories, yet less weight. We’ve seen this before. Same calorie restriction, yet more weight loss eating more plant-based: slimmer waist, less body fat. This may be from the fewer branched-chain amino acids in plant protein compared to animal protein. Or, because the resting metabolic rate in those eating vegetarian is as much as 20 percent higher; so, you’re basically just burning more calories in your sleep.
Finally, today – we look at the different impacts of plant versus animal protein.
So, are these plant-based burgers healthy or not? And the answer is…compared to what? Eating is kind of a zero-sum game; every food has an opportunity cost. I mean, every time we put something in our mouth, it’s a lost opportunity to put something even healthier in our mouth. So, if you want to know if something is healthy, you have to compare it to what you’d be eating instead. So, for example, are eggs healthy? Compared to a breakfast link sausage? Yes! But compared to oatmeal? Not even close. But look; sausage is considered a group 1 carcinogen. In other words, we know consumption of processed meat causes cancer. Each 50-gram serving a day––that’s a single breakfast link––was linked to an 18 percent higher risk of colorectal cancer. So, the risk of getting colorectal cancer eating one link a day is about the same as the increased risk of lung cancer you’d get breathing second-hand smoke all day living with a smoking spouse. So, compared to sausage, eggs are healthy, but compared to oatmeal, eggs are not.
So, when it comes to Beyond Meat and the Impossible Burger, yeah, they may be better in that they have less saturated fat, but, hey, you want less saturated fat? Plant-based meat alternatives are no match for unprocessed plant foods, such as beans or lentils. And a bean burrito or lentil soup could certainly fill the same culinary niche as a lunchtime burger. But if you are going to have some kind of burger, it’s easy to argue that, the plant-based versions are healthier. There is a sodium issue, and it’s not that much, if any, lower in saturated fat, since they use coconut oil, which is basically just as bad as animal fat. There’s not much advantage on that front.
Though the total protein is similar across the board, does this matter? Is there any advantage to eating plant protein over animal protein? Let’s look at the association between animal and plant protein intake and mortality. In the twin Harvard cohorts, following more than 100,000 men and women over decades, “…after adjusting for other dietary and lifestyle factors, animal protein intake was associated with a higher risk [of] mortality, particularly [dying from cardiovascular disease], whereas higher plant protein intake was associated with [a] lower all-cause mortality”, meaning a lower risk of dying from all causes put together. So, “replacing animal protein of various origins with plant protein was associated with lower mortality”––especially if you’re replacing processed meat and egg protein, which were the worst. But, when it comes to living a longer life, plant protein sources beat out each and every animal protein source. Not just better than bacon and eggs, but better than burgers, chicken, turkey, fish, and dairy protein.
Together with other studies, these “findings support the importance of protein sources for the long-term health outcome and suggest that plants constitute a preferred protein source compared [to] animal foods.” Why? Well, unlike animal protein, plant protein has not been associated with increased levels of the cancer-promoting growth hormone IGF-1, for example. Now, soy protein is similar enough to animal protein that at high enough doses, like eating two Impossible Burgers a day, you may bump your IGF-1. But the only reason we care about IGF-1 is cancer risk, and if anything, higher soy intake is associated with a decreased risk of cancer. For example, a recent systematic review and meta-analysis found that soy protein intake was associated with a decreased risk in breast cancer mortality; we’re talking “a 12 percent reduction in breast cancer death [associated with] each 5-gram-a-day increase in soy protein intake.” But the high soy groups in these studies were on the order of more than 16 grams a day, associated with a whopping 62 percent lower risk of dying from breast cancer. More than 10 grams of soy protein a day may be good, associated with cutting breast cancer mortality risk nearly in half, and getting more than 16 grams a day may be better, which is like one Impossible Burger a day. But we simply don’t know what happens at consumption levels far above that.
Plant protein has also been linked to lower blood pressure, reduced LDL cholesterol, and improved insulin sensitivity. No wonder “substitution of plant protein for animal protein has been related to a lower incidence of cardiovascular disease and type 2 diabetes.” Indeed, 21 different studies following nearly a half million people, and “high… animal protein intakes [were] associated with an increased risk of [type 2 diabetes], whereas [even just] moderate plant protein intake is associated with a decreased risk of [type 2 diabetes].” Okay, but these were just observational studies. They all tried to control for other dietary and lifestyle factors, but you can’t prove cause and effect, until you put it to the test.
The “Effect of Replacing Animal Protein with Plant Protein on [blood sugar] Control in Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.” Even just switching out about a third of your protein from animal to plant sources yielded significant improvements in long-term blood sugar control, fasting blood sugars, and insulin.
You can do the same thing looking at cholesterol. Here’s a systematic review and meta-analysis of randomized controlled trials on the effect of plant protein on blood fats. And indeed, swapping in plant protein for animal protein decreases LDL cholesterol, and this benefit occurs whether you start out at high cholesterol or low cholesterol, whether you’re swapping out dairy, or meat and eggs, and whether you’re swapping in soy or other plant proteins.
We’ve known about the beneficial effects of soy on cholesterol going back nearly 40 years, but other sources of plant protein can do it as well. Yeah, but we’re not swapping beans for beef. These products are mostly just isolated plant proteins, mostly pea protein isolate in the case of Beyond and concentrated soy protein in the case of Impossible. If you just isolate out the plant proteins themselves are you still going to get benefits? Yes, surprisingly. Check it out.
Interestingly, the researchers concluded, that they did not ﬁnd a signiﬁcant difference between protein isolate products and whole food sources, “suggesting that the cholesterol-lowering effects are at least, in part, attributable to the plant protein itself rather than just the associated nutrients.” So, it’s not just because plant protein travels with fiber or less saturated fat. Plant proteins break down into a different distribution of amino acids; and so, it’s like if you give people arginine, an amino acid found more in plant foods, that alone can bring down people’s cholesterol. And even plant protein concentrates used in these products aren’t pure protein, retaining a few active compounds such as phytosterols and antioxidants, which also can have beneficial effects.