Is Vegan Food Actually Healthy? What Science Says

"Is vegan food healthy?" The honest answer: it depends. A diet of Oreos, chips, and soda is technically vegan but will destroy your health. A whole-food plant-based diet, on the other hand, is associated with lower rates of heart disease, type 2 diabetes, and certain cancers in every major study that has examined it. Here is what the science actually says.

What the largest studies found

Three landmark studies have shaped our understanding of plant-based diets and health outcomes. Their findings are remarkably consistent.

The EPIC-Oxford Study

The European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford) is one of the largest cohort studies of vegetarians and vegans ever conducted, following over 65,000 participants in the UK since 1993. Key findings published in the BMJ (2019) and the American Journal of Clinical Nutrition include:

• Vegans and vegetarians had a 22% lower risk of ischemic heart disease compared to meat eaters (Tong et al., BMJ 2019).
• Vegans had a lower BMI on average (23.6) compared to meat eaters (26.0).
• Vegans had lower total cholesterol and lower LDL cholesterol than all other dietary groups.
• There was a modest increase in stroke risk among vegetarians and vegans, possibly linked to lower B12 and higher homocysteine levels — underscoring the importance of proper supplementation.

The Adventist Health Study-2 (AHS-2)

This study by Loma Linda University followed over 96,000 Seventh-day Adventists in North America — a population with a wide range of dietary patterns from vegan to non-vegetarian. Published findings include:

• Vegan participants had a 15% lower risk of all-cause mortality compared to non-vegetarians (Orlich et al., JAMA Internal Medicine, 2013).
• Vegans had a 62% lower risk of type 2 diabetes compared to non-vegetarians (Tonstad et al., Diabetes Care, 2009).
• Vegan diets were associated with a 16% lower risk of all cancer incidence (Tantamango-Bartley et al., Cancer Epidemiology, 2013).
• Vegan men had 35% lower rates of prostate cancer compared to non-vegetarian men.

Appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases.

The China Study

The China-Cornell-Oxford Project, led by T. Colin Campbell and published as The China Study (2005), examined dietary habits across 65 rural Chinese counties. While methodologically controversial — it was observational and correlational — it found strong associations between animal protein consumption and rates of heart disease, cancer, and diabetes. Its key finding: populations eating the most plant-based diets had the lowest rates of chronic disease.

Whole-food vs processed vegan

Not all vegan food is created equal. The health benefits documented in these studies primarily reflect whole-food plant-based diets — built around vegetables, fruits, legumes, whole grains, nuts, and seeds. A diet of vegan junk food offers no such benefits.

What a healthy vegan plate looks like

• Half the plate: Vegetables and fruits — emphasize leafy greens, cruciferous vegetables, and colorful produce for maximum phytonutrient diversity.
• Quarter of the plate: Whole grains — brown rice, quinoa, oats, whole wheat, or sweet potatoes.
• Quarter of the plate: Protein-rich legumes and soy — lentils, chickpeas, tofu, tempeh, or beans.
• Add: A small serving of nuts, seeds, or avocado for healthy fats.

Common pitfalls and how to avoid them

1. Over-relying on refined carbohydrates

White pasta, white bread, and white rice are vegan but provide little nutrition beyond calories. A 2020 study in the BMJ found that "unhealthy" plant-based diets (high in refined grains, sugars, and fruit juices) were associated with increased cardiovascular risk, while "healthy" plant-based diets (whole grains, fruits, vegetables, legumes) were protective.

2. Ignoring key nutrients

The nutrients most commonly lacking in poorly planned vegan diets are:

• Vitamin B12 — Must be supplemented. No reliable plant source exists.
• Vitamin D — Supplement in winter or with limited sun exposure.
• Omega-3 DHA/EPA — Consider an algae-based supplement.
• Iodine — Use iodized salt or supplement, especially if avoiding seaweed.
• Iron — Eat iron-rich plants (lentils, spinach, pumpkin seeds) with vitamin C to boost absorption.

See our complete vegan supplements guide for specific dosage recommendations.

3. Not eating enough calories

Plant foods are generally less calorie-dense than animal foods. New vegans sometimes eat too little without realizing it, leading to fatigue and brain fog. If you are losing weight unintentionally, add more calorie-dense foods: nuts, nut butters, avocado, dried fruit, coconut, and whole grains.

4. Assuming "natural" means safe

Some vegan wellness communities promote raw food diets, juice cleanses, and unproven supplements. These are not supported by evidence and can be harmful. Evidence-based vegan nutrition is about eating a varied, whole-food diet with appropriate supplementation — not about purity or restriction.

What about longevity?

The Blue Zones — five regions where people live the longest (Okinawa, Sardinia, Nicoya, Ikaria, and Loma Linda) — share a common dietary pattern: they eat predominantly plant-based, with meat consumed rarely or in small amounts. The Loma Linda Adventist community, which includes many vegans and vegetarians, lives an average of 10 years longer than the general American population.

A 2016 meta-analysis published in JAMA Internal Medicine (Song et al.) analyzed data from over 131,000 participants and found that replacing 3% of calories from animal protein with plant protein was associated with a 10% lower risk of overall mortality.

The verdict

A well-planned vegan diet is not only healthy — it is one of the healthiest dietary patterns available, according to every major dietetic organization in the world. The key word is "well-planned." Eat whole foods, supplement B12, pay attention to iron, omega-3s, and iodine, and you will thrive.