The miniseries You are what you eat – Gemini Comparison has reignited the debate on whether a vegetarian or omnivorous diet is better. Watching the 4 episodes on Netflix in which 24 pairs of identical twins were subjected to a scientific study on the role of epigenetics, and in particular nutrition, there would seem to be no doubts: the twin who followed the vegan diet for 8 weeks had significantly better physical and biochemical parameters than the twin who followed an omnivorous diet for the same period of time but was considered healthy according to nutritional guidelines.
Is a vegetarian or omnivorous diet better? More on You Are What You Eat – Comparing Gemini on Netflix
At the end of the scientific study (published on November 30, 2023 with the title Cardiometabolic Effects of Omnivorous vs Vegan Diets in Identical Twins – A Randomized Clinical Trial) both groups recorded improvements in cholesterol levels and moderate weight reductions, but these trends were more evident among the twins who followed the vegan diet; Average fasting insulin levels – another indicator of cardiometabolic health – also decreased among the vegan twins, but not among the omnivorous twins, as other measures did. But we have already talked about all this in this article.
While it’s no secret that fruits and vegetables are good for you, there are also other scientific studies however which can answer the question of whether a vegetarian or omnivorous diet is better.
Research in favor of a plant-based diet
The Stanford study, hence the Netflix miniseries, It’s not the only recent evidence pointing to the benefit of plant-rich diets. A study published in December 2023 in JAMA Network Open (Low-Carbohydrate Diet Macronutrient Quality and Weight Change) found that the people who follow diets low in carbohydrates, rich in proteins and fats of plant origin and whole grainstend to gain less weight over time than those on low-carb diets with lots of animal products and refined starches.
Two recent analyzes of previously published studies also found benefits associated with plant-based diets. The first (Vegetarian and vegan diets and the risk of cardiovascular disease, ischemic heart disease and stroke) ha linked vegetarian diets to a lower risk of heart disease compared to omnivorous diets, while the second (Vegetarian or vegan diets and blood lipids), like the twin study, found that Vegan and vegetarian diets are associated with lower cholesterol levels and other markers of potential heart problems.
In general, in addition to validating plant-based diets, studies have long shown that excessive meat consumption, particularly red and processed meat, is linked to health problems such as heart disease and cancer. But is all meat consumption bad for you?
Vegetarian diet vs Mediterranean diet
The Mediterranean diet has always and universally been considered one of the healthiest eating styles in the world. It is rich in fruits and vegetables, nuts, whole grains, olive oil and lean proteins, while low in red meat, processed foods and refined sugars. But according to a new study, published in the journal Circulation (Low-Calorie Vegetarian Versus Mediterranean Diets for Reducing Body Weight and Improving Cardiovascular Risk Profile), vegetarian diets might be just as good to keep your heart healthy.
For the study, a group of Italian researchers recruited 100 overweight but healthy adults with a low to moderate cardiovascular risk profile. Half of the group began following the Mediterranean diet, while the other began following a lacto-ovo-vegetarian diet, which eliminates meat and fish but includes eggs and dairy products. After three months, they changed their diet. During and after both phases of the study, everyone underwent regular health checks.
The researchers found that both diets were good for heart health, but in different ways. The vegetarian diet led to a greater reduction in “bad” LDL cholesterol which contributes to the accumulation of plaque in the arteries, a risk factor for heart attack and stroke. The Mediterranean diet, however, led to a greater reduction in triglycerides, which at high levels can be a risk factor for the same conditions.
The researchers also found that both diets led to modest decreases in weight and body fat. With each plan, people lost an average of four pounds total, including three pounds of fat.
The results are not entirely shocking since, as can be understood even from a simple comparison, the two eating styles have a lot of overlap. Both are rich in whole grains, fruits and vegetables, legumes and nuts, although vegetarians tend to make up for the loss of meat and fish with extra beans, nuts, eggs and dairy, according to the study.
However, the eating plans are different enough to highlight the fact that there is no universal “best” diet and that there are many ways to achieve good health through food.
Other twin studies compared
AND It’s difficult to make unequivocal statements when it comes to nutrition, as people’s bodies are unique and have different needs. Another study on twins, this one from 2019, had in fact found that even people who share almost all of their DNA can have different physiological responses to the same foods.
Researchers followed about 1,100 U.S. and British adults, including 240 pairs of twins, for two weeks. They monitored participants’ blood sugar, insulin and fat levels after eating pre-formulated meals such as muffins and glucose drinks; they analyzed the microbes living in their gut and monitored their sleep and physical activity.
The foods that sent one person’s blood sugar soaring or kept their fat levels high for hours didn’t necessarily do the same for the person eating next to them, even if they were twins. Individuals even reacted differently to the same meals when they were consumed at different times of the day. These findings suggest that nutritional data alone cannot predict a particular food’s effect on health and weight.
This is not an entirely surprising finding, especially for those whose scales have refused to go down even after careful dieting. This probably happens because the scientific community does not yet fully understand the complicated matrix of genes, environment and biomarkers which influences an individual’s reactions to a wide range of foods.
Even some research on the gene-specific diet has been disappointing. A major 2018 study, for example, found that just as many people succeed (or fail) to lose weight on low-carb diets than low-fat ones, for no clear reason.
These are the reasons why many scientists are starting to hypothesize that the secret to a personalized diet could be based on the microbiome, or the colony of microbes that live in the intestine. Scientists still don’t understand much about the microbiome, but some studies suggest it affects many aspects of human health. The latest study presented at the American Society of Nutrition conference revealed that even identical twins have only about 37% overlap in gut microbes, compared to 35% of unrelated individuals, which may explain why they respond differently to foods. In light of these differences, tailoring food choices to the microbiome, not just the genome, could unlock the full potential of personalized nutrition.
But because scientists don’t yet know enough about gut bacteria or the interactions between diet and genes to offer the kind of personalized advice that would actually be helpful to dieters, for now all you can do is follow the nutritional suggestions that seem be universal, such as eating a diverse range of fruits and vegetables, reducing processed foods, and taking generic nutritional guidelines with due deliberation and without expecting immediate miracles.
Photo by Ella Olsson / Ella Olsson / Jiroe (Matia Rengel) / Ioannis Sarantis / Gabriella Clare Marino
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