What I took away from the docuseries “You Are What You Eat: A Twin Experiment”

That’s the premise for Netflix’s new docuseries You Are What You Eat: A Twin Experiment. The experiment itself, however, is really only the jumping-off point for a more far-reaching discussion about how our diet affects our health, the planet, and the welfare of animals.

Over the course of four episodes, the show follows four of the 22 pairs of twins taking part in the Stanford University study. The scientists run a series of tests to see how these differing diets affect factors like gut health, cognition, biological aging, and even sexual health.

Between the beginning and end of the experiment, the filmmakers take viewers on many detours. The series features perspectives from industry leaders, personal stories from people affected by Big Ag, and the input of activists, researchers, and politicians.

Climate change, race and class inequality, animal rights, human health. All of these issues are interconnected and inextricably linked to the food we eat. I personally was happy to see each topic get its share of attention. But if you are tuning in to solely to follow the twins through the experiment in real time, without wanting segues into the world that shaped them, be aware that this is not a straightforward narrative

Here’s an overview of some of the other areas the documentary broaches, so you know what you’re getting into.

Why do we eat so much meat, and how does it affect us?

Early in the documentary Christopher Gardner, a Stanford University nutrition scientist, posits that the modern day “standard American diet” has its roots in World War II. Because many Americans back then were undernourished and therefore unqualified for the military, the government began pushing a diet with higher calories and protein levels from animal products.

With this mindset still the norm today, the factory farming industry has grown exponentially while streamlining to produce the most possible meat for the cheapest possible cost. This system’s efficiency comes at the expense, however, of animal welfare and human health.

The series references a 2015 World Health Organization (WHO) report which found that processed meat from animals is “carcinogenic to humans,” and that red meat in general is “probably carcinogenic to humans.” This conclusion came after 22 scientists from 10 different countries evaluated more than 800 studies.

The beef with beef

The documentary also gets in-depth about animal agriculture’s impact on the planet. It’s estimated that up to one-third of human-made greenhouse gas emissions originate from agrifood systems. A 2021 paper published in the journal Nature Food found that the majority of those emissions, nearly 60%, come from raising livestock.

The beef industry is a veritable sustainability nightmare, according to the series. It takes thousands of gallons of water just to produce a single pound of beef. One cow belches about 220 pounds of the highly potent greenhouse gas methane every year (there are nearly 40 million beef and dairy cows in the US alone).

Meanwhile, clearing land for cows to graze on is the largest driver of deforestation of any commodity. The industry has had a devastating effect on the deforestation of the Amazon rainforest in particular, where demand for beef has only grown since the COVID-19 pandemic created disruptions in the United States’ domestic supply chains.

There’s no escape for those who live too far, or those who live too close

This series also discusses the role that race and poverty have on people’s abilities to eat wholesome, nutritious meals. Low-income areas where people face daily obstacles from accessing fresh and healthy foods are known as “food deserts.” People living in these food deserts are at heightened risks of obesity, cardiovascular disease, and diabetes.

People living by the start of the US supply chain fare no better, as they suffer physical ailments and a detrimental quality of life. When massive factory farms, sometimes known as concentrated animal feeding operations (CAFOS), move in next door, its neighbors are subjected to a host of adverse health effects, mental health issues, and according to one study, higher rates of infant mortality.

In communities especially inundated with CAFO development, the detrimental effects of factory farming have mobilized residents to organize and advocate for just, more sustainable farming through activism and reporting of pollution levels.

What did the experiment find? (Spoiler alerts ahead!)

The eight-week experiment wasn’t long enough to gather definitive evidence on all the health effects monitored, such as seeing a significant impact on participants’ cognitive abilities before and after the study.

However, there were other areas where the researchers saw far more dramatic results. The twins on the vegan diet saw around a 10% decrease in their “bad cholesterol” (which can increase risk of heart disease). The twins on the omnivore diet saw theirs stay about the same, or increase slightly.

Similarly, the vegan twins saw a sharp decrease in their levels of trimethylamine N-oxide, or TMAO. Elevated TMAO levels have been linked to a number of adverse health conditions, such as hypertension, renal failure, and metabolic syndrome.

The most surprising finding for the researchers was related to the twins’ biological ages. As opposed to chronological age, which is simply how old you are, biological age refers to age of the cells in your body. One way to measure biological age is to measure the length of telomeres, which the documentary defines as “protective caps on the ends of strands of DNA.” The researchers were shocked to find that in this brief timeframe, the vegan diet yielded longer telomere lengths compared to the omnivore diets, making the twins who ate vegan biologically younger than their sibling.

The stark findings of the experiment inspired many of the twins to either continue or begin cutting animal products from out of their diet. As one participant said, “There are just too many benefits to cutting [meat] out, and not enough benefits to keep it in.”

Is it worth the watch?

I’m happy that I watched You Are What You Eat: A Twin Experiment. The docuseries alternates focus between in-depth interviews with advocates and scientists about the impacts of our food system, and the lighter and more relatable narrative of the four pairs of twins navigating learning how to eat more consciously and exercise more regularly. This kind of storytelling ends up making a pretty compelling case for adopting plant-based eating habits.

Overall, I’d recommend giving this series a watch. It covers so much ground over the four episodes, I think nearly everyone—vegan or not—could learn something to think more deeply about the way they eat.