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Doctor examines virtues, drawbacks of eating meat


Last month, I confessed that my family and I have decided to follow a mostly plant-based diet and cut out all meat aside from some occasional fish. This predictably led to some friends and readers politely telling me that I need to read more about the Paleo diet. One reader went to the length of sending me Internet links to videos and scientific papers.

I am grateful for the input, and while I’m still sticking to a mostly plant-based diet, I’m willing to examine the argument for eating meat.


Hundreds of thousands of years ago, when pre-human primates evolved into homo sapiens, we did so by forming a larger and larger brain.  To form this amazingly complex powerhouse of intellect, we needed foods very dense in calories in a time of scarcity.

A bevy of evolutionary biologists and anthropologists  agree: Without the high protein and fat content of meat, we might never have evolved as a species. The practice of eating meat started as many as 2 million years ago, providing the catalyst for human evolution.

While I believe there are drawbacks to eating meat—and will describe those later in this column—animal meat provides every essential amino acid to the body.  Amino acids are the building blocks for proteins—proteins we need to build muscle and vital tissues and operate bodily functions.

Animal meat also supplies many vitamins and minerals—and modern-day vegans can suffer from Vitamin B12 and iron deficiency if they are not careful to diversify their diet properly.

Some of the articles people shared with me after I wrote about eating a mostly vegetarian diet pointed out research published in respected medical journals showing that the meat-heavy Atkins diet produced the greatest weight loss when compared with other commercial diets.

I had read these articles before, and I acknowledge that following a strict Paleo or Atkins diet can produce dramatic weight loss, especially in conjunction with an exercise program. My concern is that these diets can be hard for some people to adhere to and may not be sustainable.

That said, the anecdotal evidence from practitioners of the Paleo diet is positive.

I must admit that every patient, friend and acquaintance of mine who follows the Paleo diet reports feeling better, having more energy, and having great success losing weight. I have not met a single person who feels worse when following the Paleo diet (which emphasizes foods our ancestors ate, including meat, fish, fruits—and no processed foods.)

The argument is compelling: If we follow the diet that was the driver of our own evolution, we can and will be healthier.

But while I appreciate greatly the dialogue stimulated by last month’s column, I am sticking to my choice of a mostly vegetarian diet. I do so not because the Paleo diet argument has no merit, but because I see things slightly differently.

We live in an age of caloric abundance, while our ancestors needed to work to avoid starvation.  Our average life expectancy is over 80, whereas our ancestors were lucky to live to 30.

Cancer is a modern-day problem, and my reading of the science still points to an increased cancer risk with consuming animal protein.  But I concede that the increase in cancer cannot be proven beyond the shadow of a doubt to be from meat, since we live in a soup of potential stimuli for cancer.


I think my confession last month about embracing a vegetarian diet has been confused with a prescription.  I do not have, nor can I hope to have, all the answers regarding which diet is healthiest.

I think the only scientifically accurate statement is this: Trying to study our diets and how they influence health is inherently fraught with problems. The food we eat is but one of millions of factors in our environments that cause changes in our bodies.

 If we design the most rigorous research study to learn the effects of a vegetarian versus Paleo diet, we still cannot control other things—like air pollution, chemicals in the water, ambient radiation (sunlight or medical procedures), the amount of physical activity we get, etc.

With this massive caveat, I prefer level-headed advice.  Avoid processed foods and  high-sugar foods, and diversify your diet with a variety of fresh foods.  This may include meat—but try to avoid meats raised with growth hormones and antibiotics. I prefer a plant-rich diet, but I try to avoid getting veggies from a can or frozen package.

And follow the usual advice: Exercise more, don’t smoke, remain active, keep your stress level low, get eight  hours of sleep each night, and try to do your own research about your diet.

Last month, I recommended watching the documentary “Forks Over Knives,” which described the theory that consuming animal meats increases our risk of cancer. This month, I will recommend two more documentaries: “Food, Inc.” by Robert Kenner and the just-released “Weight of the Nation,” which aired on HBO last week. It  is available free on YouTube and online.

Neither documentary advocates a particular diet, but rather lays out a myriad of ideas to stay healthy in our society. Living a comprehensively healthy lifestyle and avoiding obesity are likely much more important to your health than if you choose a Paleo or vegetarian diet.

Dr. Christopher Lillis is an internist with Chancellor  Internal Medicine in Fredericksburg. He can be reached  at healthyliving@freelance

ON THE WEB: To learn more about various eating styles and how food affects our health, visit these websites: