Many nutritionists have preached about the benefits of vegan eating, but how beneficial is the diet really? That's what a pair of Stanford Medicine researchers tried to find out, and their results turned out to be more surprising than expected.
The recent study examined 22 identical twins for eight weeks and examined the effects of their dietary habits. One twin was instructed to follow a strict plant-based diet (free of meat, seafood, eggs and dairy products), while the other followed an omnivorous diet (including plants, meat and animal products).
"Although eating less meat is known to improve cardiovascular health, nutritional studies are often hampered by factors such as genetic differences, upbringing and lifestyle choices," the study explains. "However, by studying identical twins, the researchers were able to control for genetics and limit the other factors because the twins grew up in the same households and reported similar lifestyles."
It is the first time that researchers have conducted such a study. It is also the first time that researchers have attempted to change people's underlying biochemistry in a short period of time.
"We're taking a comprehensive approach to this research, looking at body composition, the epigenome or biological clock, the microbiome and the brain," says Christopher Gardner, a nutrition scientist at Stanford University.
The research is further explored in the Netflix food documentary 'You Are What You Eat: A Twin Experiment'. The four-part series describes the research from start to finish and reveals the results at the very end.
Four of the 22 twins appear in the series. They include sisters Pam and Wendy, who both grew up in South Africa and run several food companies together; brothers Charlie and Michael, better known as the "Cheese Twins"; sisters Carolyn and Rosalyn, a sports relations coach and high school teacher, respectively; and brothers John and Jevon, two recently graduated nurses.
Here are eight of the biggest takeaways from the study:
You Are What You Eat: A Twin Experiment (Photo courtesy of Netflix)The infamous Standard American Diet, better known as SAD, became mainstream in society after World War II. Many aspiring soldiers didn't qualify for the military because they were too thin and malnourished, explains Christopher Gardner, a nutrition scientist at Stanford University.
"And there was a huge push to get enough calories and be as efficient as possible," Gardner continued. "We saw a growing availability of convenience foods, a lot of cheap foods, which then started to turn into more and more processed and packaged foods. And we saw the same thing with animal foods. Beef, pork, chicken, eggs, dairy products, cheese."
The livestock industry rapidly industrialized and factory farms soon took over to improve efficiency, said physician and author Michael Greger. Animal products decreased in cost, but increased in availability and overall consumption.
Cheap, ultra-processed foods are still a core part of our food system. High consumption of such foods has been linked to an increased risk of obesity, high blood pressure and cardiovascular disease.
A plant-based diet can contribute to lower levels of low-density lipoprotein cholesterol, also called "bad" cholesterol. Over the course of eight weeks, researchers found that LDL cholesterol dropped significantly among those who followed a vegan diet.
Carolyn's LDL levels decreased by 12.9%, while her sister Rosalyn's increased slightly by 1.7%. High levels of LDL cholesterol can clog arteries and cause heart disease and stroke.
While the omnivores in the study saw their LDL cholesterol remain the same on average, the vegans saw their LDL cholesterol levels drop by an average of 10%.
While neither twin has gone completely vegan, many said they are committed to eating more plant-based meals in their regular diets.
"For me, plant-based eating is the right choice," says Carolyn. "I feel healthier. . . If I put crap in my body, I'll feel bad too. But if I do the opposite, it will be even better."
As for Pam and Wendy, the sisters have reduced their intake of animal products. When it comes to eating meat, "less is more," Wendy said.
"Change starts with one person," Pam added. "By making food for other people, we realize that we don't need so much meat."
Michael expressed similar sentiments, saying he has "left out meat for the most part."
"I think there's just too many benefits to leaving it out, and not enough benefits to keeping it in," he said.
"You Are What You Eat: A Twin Experiment" is currently available for streaming on Netflix. Watch a trailer for it below, via YouTube:
