The impact of diverging dietary choices: The story of one vegan identical twin and their non-vegan sibling
A study found that one twin who followed a vegan diet for two months experienced better health compared to their identical sibling who ate a meat and vegetable diet Discover the benefits of high-fiber plant foods and explore the week 1 menus for both vegan and omnivore diets
Join CNN's Eat, But Better: Mediterranean Style and discover a delicious expert-approved eating lifestyle designed to improve your overall health. Our comprehensive eight-part guide will show you the way to a healthier life.
According to a recent study, twins who followed a vegan diet for eight weeks experienced lower levels of "bad" LDL cholesterol, improved blood sugar levels, and greater weight loss compared to their siblings who followed a diet of meat and vegetables.
Hand opening a frozen pizza
Shutterstock
Ultraprocessed foods now account for two-thirds of calories in the diets of children and teens
Lead study author Christopher Gardner, a research professor of medicine at the Stanford Prevention Research Center in Palo Alto, California, reported significant results after just eight weeks, including a 10% to 15% drop in LDL cholesterol, a 25% drop in insulin, and a 3% drop in body weight, all from consuming real food without animal products. He explained that a vegan diet, with its exclusion of animal flesh, dairy, eggs, and other animal-derived ingredients, differs from a vegetarian diet. Gardner also emphasized that a plant-based diet can offer higher levels of fiber, vitamins, minerals, and phytonutrients compared to other dietary patterns.
Alice Lichtenstein, Director and Senior Scientist at Tufts University's Cardiovascular Nutrition Laboratory, confirmed in an email to CNN that the study results support the current dietary guidance for reducing the risk of cardiovascular disease. She stated that a diet higher in unsaturated fat, whole grains, fiber, and vegetables, while lower in saturated fat, refined grains, calories, and cholesterol, resulted in a more beneficial cardiovascular disease risk factor profile compared to the comparison diet.
The study was unique in that it utilized genetically identical twins, the majority of whom had similar lifestyle habits such as haircuts and clothing choices.
Dr. Frank Hu, a professor at the Harvard T.H. Chan School of Public Health in Boston, commented, "The twin study design is sophisticated because it effectively manages genetic and environmental factors that could impact the results of the trial." He was not part of the study.
Hu noted that recruiting identical twins for dietary intervention studies is quite challenging, which is why this design has been infrequently utilized in nutritional research. Furthermore, the results obtained from identical twins may not be applicable to the general population.
Identical twins help scientists control variables that may otherwise influence trial results. (The twins seen above did not participate in the new study.)
filadendron/E+/Getty Images
High-fiber plant foods with low fat offer significant advantages. A recent study in the JAMA Network Open paired 22 sets of identical twins, with one twin following a vegan diet and the other an omnivore diet for eight weeks. Meals were provided for the first four weeks to ensure adherence to the respective diets.
CNN
Interactive: Do you know how much ultraprocessed food you consume?
"I think many people who follow a vegan diet mistakenly believe that soda and pancakes are healthy because they are vegan. In reality, they are made from refined ultraprocessed grains," Gardner explained. "Therefore, we aimed to educate individuals about the components of a healthy vegan diet by providing a four-week demonstration."
The meat and vegetable group received upgraded meal deliveries that were a departure from their usual food options. "I prioritize balance in my studies. I don't follow an extremely healthy vegan diet or a subpar diet that's easy to criticize," Gardner explained. "Those who followed an omnivorous diet consumed more vegetables, whole grains, less added sugar, and fewer refined grains compared to their normal diet. They also consumed high-quality meat. These changes led to improvements in their overall diet."
Vegan Week 1 Menu:
- Strawberry almond oatmeal
- Cinnamon blueberry oatmeal
- Tofu scramble with plant-based breakfast sausage
- Coconut curry spinach and chickpeas with quinoa
- Black bean bowl with tofu
- Buffalo beans with cauliflower
- Chipotle-lime cauliflower with plant-based chicken
- Lentils and herb-roasted potatoes with remoulade sauce
- Harissa chickpeas with sumac carrots and broccoli
- Tofu with coconut curry brown rice
After learning about the types of foods to eat, each pair of twins was tasked with creating their own meals and snacks that fit their dietary needs for the second part of the study, according to Gardner.
Biological markers such as blood and feces were collected from each twin at the beginning of the study, as well as at week four and eight. Interestingly, twins following a vegan diet showed signs of being biologically younger than their chronological age, and this data will be shared in a future study, Gardner explained.
Gardner noted that it was expected to see improvements in cardiovascular biomarkers, such as lower LDL cholesterol, insulin resistance, and weight loss. He explained, "The vegetarians consumed more fiber and less saturated fat, which can account for the lower LDL cholesterol. The increased fiber intake also explains the lower fasting insulin levels, as it leads to a slower release of glucose in the bloodstream." Additionally, he pointed out that the bulkier nature of vegetables, fruits, and grains compared to meat may lead to increased satiety and consumption of fewer calories.
Restricted diets
But as with all diets that restrict people from foods they are used to eating, staying the course can be tough.
Omnivore Week 1 Menu:
- Egg whites, turkey bacon, and Brussels sprouts
- Mushroom and spinach frittata
- Chicken fajita scramble with zucchini, squash, and tomatoes
- Sunny-side up egg with asparagus and tomato
- Cajun Yukon potato and brown rice with chicken
- Honey Dijon steak with vegetables and rice
- BBQ chicken with broccoli and quinoa
- Roasted pepper burger with kale and jasmine rice
Honestly, twins following a vegan diet felt less satisfied due to its restrictive nature. On the flip side, they realized that despite being able to eat more, they simply weren't hungry for additional grains and vegetables.
Gardner emphasized that while there are quick health improvements with a vegan diet, one doesn't have to become vegan to benefit from the study findings. Gradually reducing meat and animal byproducts consumption can also be beneficial.
Harvard's Hu concurred, stating that although the study indicated potential benefits of a vegan diet over a healthy omnivorous one, it does not imply that everyone should adopt a vegan or vegetarian lifestyle. He emphasized that dietary choices are influenced by individual health conditions, personal preferences, cultural traditions, and ethical and environmental factors.
