What is the difference between vegetarians and nonvegetarians?

December 24, 2025 •

3 min read

According to a study from the Adventist Health Study-2, non-vegetarians generally have a higher mean BMI compared to strict vegetarians, suggesting a fundamental contrast in dietary patterns that goes beyond simple food choices. This distinction touches on a wide range of factors including nutritional content, health implications, and ethical beliefs, all of which contribute to a person's overall lifestyle.

Quick Summary

The key difference lies in dietary choices: vegetarians exclude animal flesh, while nonvegetarians consume it. These choices influence nutritional intake, long-term health outcomes, and environmental footprints, reflecting varied personal, ethical, and cultural beliefs.

Key Points

Dietary Distinction: Vegetarians exclude animal flesh from their diet, while nonvegetarians consume it as part of an omnivorous diet.
Nutritional Focus: Vegetarians emphasize plant-based sources like legumes, grains, and nuts, while nonvegetarians also rely on meat, poultry, and fish for protein and certain vitamins.
Health Outcomes: Studies suggest vegetarians often have lower risks of heart disease, type 2 diabetes, and certain cancers due to lower saturated fat intake and higher fiber content.
Nutrient Deficiencies: Vegetarians, especially vegans, must plan carefully to ensure adequate intake of vitamin B12, iron, and omega-3 fatty acids, which are abundant in animal products.
Environmental Footprint: Vegetarian and vegan diets typically have a lower environmental impact in terms of greenhouse gas emissions, land use, and water consumption compared to diets heavy in meat.
Variations Exist: Vegetarianism has sub-types like lacto-ovo, lacto, and ovo, which differ in their consumption of eggs and dairy, while veganism is the strictest form, avoiding all animal products.
Holistic Lifestyle: Veganism often extends beyond diet to a broader lifestyle avoiding animal products in clothing and other goods, unlike many vegetarians who focus primarily on food.

The choice of diet is one of the most fundamental decisions an individual makes, influencing their health, personal values, and impact on the world. The primary distinction between vegetarians and nonvegetarians rests on whether they consume animal flesh. However, this seemingly simple difference opens up a complex array of variations in diet, nutrition, and lifestyle. This article explores these differences in detail, offering clarity for anyone interested in understanding these dietary paths.

Core Differences in Diet

The most basic difference is the avoidance of meat, poultry, and fish by vegetarians, while nonvegetarians include these animal products in their diet. This core distinction branches into several categories for vegetarians based on other animal products they may consume.

What Vegetarians Eat

Vegetarian diets are centered on plant-based foods such as fruits, vegetables, grains, legumes, nuts, seeds, and fungi. Several sub-types exist based on the inclusion or exclusion of other animal products:

Lacto-ovo-vegetarians: Consume dairy and eggs.
Lacto-vegetarians: Consume dairy but no eggs.
Ovo-vegetarians: Consume eggs but no dairy.
Vegans: Exclude all animal products, including dairy, eggs, and honey.

What Nonvegetarians Eat

Nonvegetarians, also known as omnivores, incorporate both plant-based foods and animal products into their diet. This includes meat, poultry, fish, seafood, eggs, dairy, and all the plant-based foods eaten by vegetarians.

Nutritional Considerations

Both diets can be nutritionally complete with careful planning.

Nutritional Aspects of a Vegetarian Diet

Vegetarian diets are typically high in fiber and antioxidants and lower in saturated fat and cholesterol. However, particular attention is needed for nutrients mainly found in animal products, including vitamin B12, easily absorbable iron, zinc, and long-chain omega-3 fatty acids.

Nutritional Aspects of a Nonvegetarian Diet

Nonvegetarian diets offer complete protein and are rich sources of vitamin B12, easily absorbed iron, zinc, and omega-3 fatty acids from animal products. However, high consumption of red and processed meats can lead to higher intake of saturated fat and cholesterol.

Comparison of Key Aspects


Aspect	Vegetarians	Nonvegetarians
Dietary Components	Plant-based foods; may include dairy, eggs, or honey	All plant-based foods, plus meat, poultry, fish, and other animal products
Primary Protein Sources	Legumes, tofu, nuts, seeds, grains; dairy and eggs for some	Meat, poultry, fish, dairy, eggs, plus all plant-based sources
Saturated Fat & Cholesterol	Typically lower	Can be higher, especially with high intake of red/processed meat
Dietary Fiber	Higher due to emphasis on plant foods	Lower, as animal products contain no fiber
Primary Vitamin B12 Source	Fortified foods, supplements; dairy and eggs for some	All animal products
Iron Absorption	Less efficient (non-heme iron), requires vitamin C to aid absorption	More efficient (heme iron)
Environmental Impact	Significantly lower greenhouse gas emissions, land, and water usage per calorie	Higher environmental footprint due to livestock farming

Health Impacts and Longevity

Research suggests varied health outcomes, though healthy diets are possible for both. Well-planned vegetarian diets are associated with a lower risk of heart disease, certain cancers (like colorectal and prostate), type 2 diabetes, and a tendency for lower body weight. Nonvegetarian diets, especially those high in red and processed meats, can be associated with increased health risks. The overall quality and balance of the diet are critical for health outcomes.

Ethical and Environmental Drivers

Dietary choices are often influenced by ethical beliefs and environmental concerns.

Ethical Standpoints

Many choose vegetarianism due to ethical opposition to killing animals for food or to animal exploitation in industries producing dairy and eggs. Nonvegetarians' ethical views vary, often involving cultural reasons, nutritional needs, or focusing on humane animal treatment and responsibly sourced meat. For further reading on the ethical dimensions, see this University of Oxford blog post: The ethical arguments against eating meat.

Environmental Impact

The environmental footprint of livestock farming is a major concern for many vegetarians and vegans. Meat production requires significant resources (land, water, energy) and contributes substantially to greenhouse gas emissions, deforestation, and water pollution. Plant-based diets generally have a lower environmental impact, with vegan diets often having the lowest.

Conclusion

The distinction between vegetarians and nonvegetarians involves dietary choices, nutritional intake, health outcomes, and ethical and environmental perspectives. Vegetarians exclude animal flesh, focusing on plant-based foods, which often results in higher fiber and lower saturated fat intake. Nonvegetarians consume both plant and animal products, benefiting from readily available B12 and highly absorbable iron. While both diets can be healthy, the quality of food choices within each framework is paramount for long-term wellness. Ultimately, the decision between these dietary paths is personal, shaped by health needs, values, and cultural background.

Frequently Asked Questions

Not automatically. While well-planned vegetarian diets are linked to lower rates of heart disease and other health issues, a poorly planned vegetarian diet can lack key nutrients. Similarly, a nonvegetarian diet can be very healthy if it's balanced and emphasizes lean meats and plenty of plant-based foods.

Vegetarians get protein from a variety of plant-based sources including legumes (beans, lentils), nuts, seeds, soy products (tofu, tempeh), and whole grains. Lacto-ovo vegetarians also consume protein from dairy products and eggs.

The biggest concern is vitamin B12 deficiency, as this nutrient is found almost exclusively in animal products. Vegans must consume B12-fortified foods or take supplements. Other areas to monitor include iron, zinc, and omega-3 fatty acids.

Meat production, particularly red meat, has a higher environmental footprint due to greater greenhouse gas emissions, water usage, and land requirements for feeding and grazing animals. Plant-based diets generally have a significantly lower environmental impact.

Vegetarians can get enough iron from plant sources like lentils, beans, and leafy greens. However, the iron from plant sources (non-heme iron) is less easily absorbed by the body. Eating vitamin C-rich foods alongside iron sources helps to improve absorption.

Ethical considerations are a personal matter. Some nonvegetarians argue that it is part of human nature to eat meat, while others prioritize responsible sourcing and support practices that ensure humane treatment of animals. Many also choose to reduce their meat intake without eliminating it entirely.

A vegetarian avoids animal flesh but may consume animal by-products like dairy, eggs, or honey. A vegan avoids all animal products and by-products entirely. Veganism is often a broader lifestyle choice beyond just diet.