Twin diet study: Omnivore vs vegan – which is better? - opinion

There is no shortage of good studies that analyze the effect of lifestyle, and especially diet, on our health. These studies run the gambit in terms of types. There are randomized control studies, epidemiological studies, laboratory studies and decades of clinical observations. And there are thousands of them. 

These studies all reach similar conclusions in terms of the positive effect of eating a plant-predominant diet, exercising, getting enough sleep, not abusing substances and controlling our stress.

However, the way these studies on health are set up, there are almost always imperfections. One can always find fault somewhere, no matter what study one looks at. But what happens when we put together a study that eliminates one of the biggest question marks in any investigation on humans: genetic makeup? How much do genes play a part in health as opposed to lifestyle behaviors?

Despite the recent evidence available, there are still many who believe that “it’s all genes.” Dr. Christopher Gardner, a nutrition scientist and researcher at Stanford University, found a great way to put this to the test. 

He set up an experiment where he randomized 22 sets of identical twins from Stanford’s twin research registry into two groups. Each twin was to either eat a healthy omnivore diet (both meat- and plant-based) or a healthy vegan diet. The emphasis here is on the word “healthy.” No junk food on either diet. 

For the first month of the experiment, food was brought to each participant’s home and during the second four weeks, they were required to prepare their own food. Setting up the study this way eliminated the problems of age, gender and genetic factors.

Multi-test objectives

THERE WERE many things that the study’s authors wanted to test. How would both the omnivores and the vegans fare when looking at factors such as LDL cholesterol, biological aging through measuring the telomeres in the DNA strands, microbiome function, body fat and muscle mass, brain function, fasting insulin levels and overall weight? The healthy omnivorous diet group was told to eat enough animal products daily to differentiate from the vegan group. Specifically, this included targets of six to eight ounces of meat, fish or poultry, one egg, and one-and-a-half servings of dairy each day, on average.

Aside from animal products, targets included three servings of vegetables, two servings of fruit, and six servings of grains or starchy vegetables each day. 

The healthy vegan diet group was told to avoid all animal products for the course of the study. Specific targets included six or more servings of vegetables, three servings of fruit, five servings of legumes, nuts, seeds, or vegan meat, and six servings of grains or starchy vegetables each day.

All study participants were told to choose minimally processed foods and to build a balanced plate with vegetables, starch, protein, and healthy fats. They had to choose variety within each food group and individualize these guidelines to meet preferences and needs.

After eight weeks, the vegan group did better all the way around. They lost more weight, their LDL cholesterol dropped more, they showed a much healthier microbiome, younger biological aging, and better fasting insulin and triglycerides levels. In some categories, the differences were quite pronounced. 

The results of the study were published in the highly respected Journal of the American Medical Association (JAMA) under the title “Cardiometabolic Effects of Omnivorous vs Vegan Diets in Identical Twins – A Randomized Clinical Trial” by co-first authors Drs. Matthew J. Landry and Catherine P. Ward, with Gardner as corresponding author. 

The complete results of this study are available online – and if you want an easy way to see it, watch the Netflix documentary called, “You are what your eat.” It is worth watching.

PROFESSOR GARDNER and his colleagues succeeded in confirming what we already knew, but he did it in a way that put to rest the role of genetics. How much influence do genes have in the overall picture of ischemic (blood flow blockage) heart disease and of chronic disease in general? Many researchers are putting that number as less than 10%.

One of the things the study examined was the influence of behaviors on epigenetics. That is to say, our genes are our genes – you can’t change them – but epigenetics examines what turns various genes on and off and yes, food has a big part to play. The bottom line here is simply that the more plants make up your diet and the less meat, poultry and fish, the better off you are.

Although it’s only anecdotal, day after day I see with my own eyes how people who are pretty sick turn their various chronic conditions around. Just this past week, two of my clients in follow-up visits with their cardiologists were able to reduce some of their medications, and they are both only beginning. One of the cardiologists couldn’t get over the sustained weight loss that my client was having.

It’s impressive to see various markers on blood tests and their blood pressure improving all the time. Best of all is that both clients have reported back to me feeling better and better as the weeks go by.

When it came to the twins, keep in mind they all come from the same home, the same eating habits and, of course, they are genetically identical. 

This study more than any other demonstrates that changing our diet and lifestyle, at any age will have a pronounced, positive effect on health and longevity. In this regard, it is more powerful than any pill that can be swallowed or surgery that can be performed. 

The evidence is pretty indisputable. If you eat a diet that is very low in animal proteins, very low in processed foods and very high in vegetables, fruits, whole grains and legumes with some nuts and seeds, you will live better, live longer and you will “add hours to our day, days to your year and years to your life.”

The writer is a health and wellness coach and personal trainer with more than 25 years of professional experience. He is director of The Wellness Clinic, and can be reached at alan@alanfitness.com.