The Pros and Cons of a Plant-Based Diet

By: Annabelle Shaffer, Dietetics senior at University of Illinois Urbana-Champaign

The definition of a plant-based diet is very broad in the media. For instance, a US World News and Report found twelve variations of the diet to rank including the Mediterranean Diet, the Flexitarian Diet, the Ornish Diet, and the most commonly thought of Vegetarian and Vegan diets. All of these variations beg the question: what exactly is a plant-based diet and what are the pros and cons?

Let’s break down the definition:

“A plant-based diet consists of all minimally processed fruits, vegetables, whole grains, legumes, nuts and seeds, herbs, and spices and excludes all animal products, including red meat, poultry, fish, eggs, and dairy products” (Ostfeld, 2017).

This definition is differentiated from a traditional vegan diet (the complete elimination of all animal products, including meat, poultry, fish, eggs, dairy, and honey) by the focus on whole foods. The plant-based diet is restrictive, which leads us to the discussion of pros and cons:

Pros of following a plant-based diet:

The diet shows promise in the reduction of diabetes risk:

Based on three prospective cohort studies, it was found that “having a diet that emphasized plant foods and was low in animal foods was associated with a reduction of about 20% in the risk of diabetes” (Satija, et. al., 2016).

The eating plan may be a successful weight management diet:

A study consisting of nearly 50,000 participants compared the BMIs and diabetes risk of those following a vegan diet, vegetarian diet, and its variations, and an omnivore diet. The results showed that the average BMI of vegans was 23.6 kg/m2 and 28.8 kg/m2. The authors concluded that “vegetarian diets may play a beneficial role in promoting health and preventing obesity” (Tonstad, et. al., 2009).

Plant-based diets may also be a cardio-protective diet:

A case-control study found that vegans had significantly lower systolic blood pressure, fasting glucose and triglyceride levels (Goff, et. al., 2004). As stated by the authors, this cardio-protective mechanism of the vegan diet may be due to high intakes of complex carbohydrates and polyunsaturated fatty acids, and significantly lower intakes of animal proteins and saturated fatty acids.

Like any eating plan, a plant-based diet has its cons:

While nutrition deficiencies in plant-based eaters can occur, the media has blown this out of proportion. In the Position of the Academy of Nutrition and Dietetics: Vegetarian Diets, it is stated that even though vitamin B12 and iron deficiencies can occur in plant-based eaters, many achieve adequate iron intake through plant-based sources (leafy greens, soy products, lentils, and others) and adequate vitamin B12 intake fortified foods (enriched cold cereals, enriched breakfast shakes, and more) (Melina, et. al., 2016).

The restrictiveness of a totally plant-based diet would mean giving up many of your favorite foods, such as hamburgers or ice cream. Although the cost of healthy food versus less nutritionally dense foods has shown to be insignificant, the perceived cost may be a barrier for some. The good news is that a plant-based diet is not an all-or-nothing deal. For example, the Mediterranean Diet, which is rich in plant-based foods but does not eliminate anything, has shown promise in chronic disease prevention (Widmer, et. al., 2015).

In conclusion, the plant-based diet shows promise in the protection against chronic disease. A well-planned plant-based diet can be nutritionally adequate and sustainable. Other diets, with a focus on fruits, vegetables, and whole grains, have similarly positive impacts on health as a plant-based diet.

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  1. Best Plant-Based Diets. US News and World Report. Published 2018. Accessed October 9, 2018.
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