As Dr. Michael Greger, Founder of NutritionFacts.org, points out: Veganism only states what you exclude from your diet, not what you include. So, eating a vegan diet does not inherently equate to eating an optimal diet for human health. 

The most respected proponents of a plant-based way of eating tend to champion a predominantly whole food, plant-based diet, rather than a vegan diet.

A vegan diet is not a panacea. The quality of the diet determines its effect. 

What makes a vegan diet healthy or unhealthy? 

Plant-based index (PDI) is often used to measure this; there’s a healthy PDI and unhealthy PDI.

According to Plant-Based Nutrition in Clinical Practice: a healthy PDI emphasises ‘healthy plant foods’ such as fruits, vegetables, whole grains, tea and coffee, and vegetable oils. It’s associated with a significant reduction in several diseases including major killers such as cancer and heart disease, as well as all-cause mortality. 

Those who follow a healthy PDI may find it easier to lose or maintain weight due to a high intake of low energy-density, high nutrient-density foods. Obesity increases the risk of morbidity and mortality, and as reducing weight by 5-10% in obese individuals confers a clinically meaningful reduction, this is no small thing.

An unhealthy PDI emphasises ‘unhealthy plant foods’ such as fruit juice, refined grains, sweets and desserts, and sugar-sweetened beverages and limits ‘healthy plant foods.’ This way of eating is associated with an increased risk of all-cause mortality and several diseases. 

An unhealthy plant-based diet isn’t generally considered to be much better than the ‘standard Western diet.’

Are there other diets which are as good as a healthy PDI?

Mediterranean or DASH (Dietary Approaches to Stop Hypertension) are consistently shown to be good ways to eat for individual health; perhaps as good, or better than, a healthy plant-based diet, depending on what is being measured.

A Mediterranean or DASH diet is almost certainly better for individual health than eating an unhealthy plant-based diet. 

Is plant-centric sufficient for optimal individual health?

What do a vegan, Mediterranean, and DASH approach have in common? They are all plant-centric; sometimes all three approaches are defined as a plant-based diet.

One unequivocal point is eating lots of plants is good for health. They’re higher in antioxidants on average than animal foods (which is important as chronic inflammation is implicated in diseases). Also, only plants contain fibre, which is essential for optimal health; it’s not feasible to get the 30g fibre RDA without plants. 

As Dr. Greger often states when discussing whether something is healthy: “Compared to what?”

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