Benefits of a Plant-Based Diet

written by Amy Howton an associate professor from Kennesaw University

There is a lot of information about plant-based lifestyles in the media today. As far back as the turn of the 20th Century, preliminary research showed the risk of chronic lifestyle diseases was higher when more animal products were consumed. Why did this not reach the mainstream?

The USDA was originally formed to promote the meat and dairy industries’ products, and recommendations used to reflect this.1 Additionally, we in the U.S. tend to dismiss evidence we don’t like, and we are also conditioned only to consider clinical trials as producing true information. It is very difficult to obtain usable insights from clinical trials when it comes to food, because a person must be sequestered and all food intake monitored in order to get verifiable results. Because people will eventually leave the lab and eat on their own, and because it may take decades for the chronic disease to fully develop, there are too many confounding variables to make the trial useful. In addition, because fresh produce cannot be patented, it is difficult to obtain funding to study it. We must rely on epidemiological, or observational, research.

Even with these restrictions, some major recommendations were released between 2010 and 2013. The Dietary Guidelines for Americans 2010 finally recognized that vegetarian diets can provide all necessary nutrients required by our bodies while reducing risks of chronic diseases. By 2013, the Mayo Clinic and the largest HMO in the U.S., Kaiser Permanente, had published their recommendations that people should eat a plant-based diet. While Kaiser “encourages whole, plant-based foods and discourages meats, dairy products, and eggs as well as all refined and processed foods,”2 the Mayo Clinic allows “less than 20 grams a day”3 of meat—less than one ounce—in an optimal diet.

One of the reasons for adopting a plant-based lifestyle is that higher consumption of fruits and vegetables is associated with normal weight and weight maintenance.4 Since obesity is linked with almost all chronic lifestyle diseases, this could drastically reduce disease risk in developing countries where animal products and processed foods are eaten in the largest quantities.

With the popularity of high-meat “Paleo” diets, anthropologists are now examining fossilized human waste to see what humans actually ate in the Paleolithic era—and discovering a very high dietary fiber content. The findings are that Paleo humans consumed about 100 grams of dietary fiber from plants every day, whereas 21st Century U.S. humans consume less than 20. One of the mechanisms that controls hunger is related to the total fiber we eat, and a cycle of short-chain fatty acids made by our gut bacteria which then cause a release of hormones that make us less hungry. It is now theorized that we are not getting the signals to stop eating because our bodies don’t get the amount of dietary fiber needed for the body to send “stop eating” signals.5,6

So what to do? To begin testing the waters, just add more fruits, vegetables, legumes (beans), and whole grains (brown rice, oatmeal, barley, etc.) to your diet. They can be cooked or raw. If you added one of these nutritious plant-based items each meal, you would be well on your way to dietary improvements. Eat your new additions first, then your old favorites. Each week, you can add one more serving somewhere in your day. Take it slowly to let your body adjust and enjoy. 

Next month: Is it more expensive to live a plant-based lifestyle?

2 Tuso, P. J. (2013). Nutritional Update for Phpysicians: Plant-based Diets. Permanente Journal, 61-66.

3Jennifer Nelson, M. R. (2013, April 24). Nutrition and Healthy Eating. Retrieved from

4Champagne CM, B.S. Dietary intakes associated with successful weight loss and maintenance during the weight loss maintenance trial. Journal     of the American Dietetic Association, 2001. 1826-1835.

5K M Tuohy, C Gougoulias, Q Shen, G Walton, F Fava, P Ramnani. Studying the human gut microbiota in the trans-omics era–focus on metagenomics and metabonomics. Curr Pharm Des. 2009;15(13):1415-27.                                                                                                          6Frost, G E Walton, J R Swann, A Psichas, A Costabile, L P Johnson, M Sponheimer, G R Gibson, T G Barraclough. Impacts of plant-based foods in ancestral hominin diets on the metabolism and function of gut microbiota in vitro. MBio. 2014 May 20;5(3):e00853-14.

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