"You Are What You Eat" Documentary: A Review

Should we be eating meat?

I've had a lot of clients ask me about this new Netflix Documentary, which follows identical twins as they participate in a nutrition-focused health study. When I first heard about it, I was excited because it is really difficult to create and conduct meaningful human nutrition studies. Using twins is a really genius way to accurately compare results since their genetics are almost identical. 

Overall Impression: Entertaining, but political

I watched the documentary and it was entertaining with a few compelling results. What surprised me was the political agenda threaded through the actual study. The show toggled back and forth between following the light-hearted health journeys of the twins then jolting us over to examples of horrific commercial meat operations and the detrimental environmental effects of the meat industry. It also show-cased vegan food companies all of whom helped fund the study, which felt like a conflict of interest.

Study Premise:

Each twin was prescribed a healthy diet - one was given a healthy vegan diet and the other a healthy omnivore diet. The first two weeks their meals were delivered to their homes, so no cooking was involved. The last few weeks, the twins were tasked with cooking their own meals while sticking to the diet guidelines.

There was also an exercise component in which participants met with a personal training crew to learn an optimal exercise routine that included weight lifting and cardio. Exercise is obviously crucial for overall health, but it definitely skewed the results of diets changes alone, making it difficult to determine if improvements were due to exercise or nutrition.

Extensive initial testing was done to set a baseline for each participant. This included blood tests, physical stamina and strength, body composition, cognitive function and even libido (which seemed to be included for entertainment value).

Results:

Vegan group:

• Lost more weight (mostly lean muscle mass, not fat loss)

• LDL (bad) cholesterol decreased

• HDL (good) cholesterol decreased

• Triglycerides increased

• Better fasting insulin

Omnivore group:

• Lost some weight (mostly fat loss, maintained or gained lean muscle)

• Cholesterol stayed the same for the most part, but did not improve

• Fasting insulin stayed stable, but did not improve

Results Review:

Overall the vegan participants lost more weight, however both groups lost some weight. The weight loss in the vegan group is mostly likely due to the fact that the vegan meals were almost 300 calories less than the omnivore meals. However, most of the weight loss in the vegan group was lean muscle mass instead of fat loss. This result was glossed over, but is very important to highlight. We put so much emphasis on weight as an indicator of success, but the wrong kind of weight loss (aks loss of lean muscle mass) can actually work against your health in a big way. For some, whose calorie needs were higher, it was difficult to eat enough food to support muscle maintenance and growth.

The vegan group reduced LDL or “bad” cholesterol levels and improved fasting insulin, both of which are very positive health results. This isn’t surprising however, because the vegan meals were much higher in fiber, which helps remove excess cholesterol and slows down digestion to improve blood sugar control. However, HDL (good) cholesterol went down, which is a negative outcome, and triglycerides went up - also a negative outcome.

Compliance with exercise (specifically the inclusion or exclusion of weight lifting) had big impact on results. Those who lifted weights were able to maintain a much higher percentage of lean muscle mass and those who mostly did cardio lost lean muscle mass.

Regarding the political/environmental agenda against the meat industry, I don’t disagree that conventionally raised meat contributes in a big way to environmental harm. It was also a reminder that prioritizing quality of meat and fish over quantity is so incredibly important, both for our health and the environment. I also agree that for some people, a vegan diet can be a healthful way to eat. BUT it doesn’t work for everyone, especially picky eaters. You have to be willing to eat high protein foods like seitan, tofu and tempeh, eat lots of veggies and pay very close attention to blood sugar control and digestive health.

Here are my main take-aways:

• Eat a large variety of fruits and veggies - 5 colors per day

• Adequate fiber is crucial for overall health

• Focus on quality and sustainability of meat products

• Mix in plant-based protein sources to help reduce overall meat consumption, increase nutrient density and maintain overall protein intake

• Weight train regularly

The documentary was entertaining and if you’re interested, watch it, but keep in mind that it is very biased. Take the results with a hefty pinch of salt.