What Happens to a Person Who Doesn't Eat Meat? A Complete Guide

November 30, 2025 •

4 min read

A 2021 review highlighted that individuals on plant-based diets often have a lower risk of chronic diseases, but what happens to a person who doesn't eat meat in the long term, and how do their nutrient needs change?

Quick Summary

Switching to a meat-free diet can lead to benefits like lower cholesterol and improved gut health, but requires careful meal planning to address potential nutritional gaps in key vitamins and minerals.

Key Points

Initial Changes: Expect shifts in gut bacteria and potentially temporary fatigue as the body adapts to a higher-fiber, non-meat diet.
Long-Term Health Benefits: A sustained meat-free diet is linked to lower risks of heart disease, type 2 diabetes, and certain cancers.
Nutrient Gaps: Careful meal planning is essential to prevent deficiencies in key nutrients like Vitamin B12, iron, zinc, and Omega-3s.
Supplementation is Crucial: Vegans, in particular, require a reliable source of Vitamin B12, often through supplements or fortified foods.
Environmental Impact: Choosing a meat-free diet significantly reduces your environmental footprint compared to a meat-based diet.
Balanced Diet is Key: Success hinges on replacing meat with a diverse range of legumes, whole grains, nuts, and seeds, not just processed substitutes.

The Immediate Physical and Mental Changes

When a person first stops eating meat, they may notice several initial changes, both in their physical health and digestive system. One of the most immediate effects is a potential shift in gut bacteria. Research suggests that plant-based diets high in fiber promote the growth of 'friendly' bacteria in the gut, which can lead to improved digestive health. However, this rapid increase in fiber can also lead to temporary digestive discomfort, including more frequent trips to the bathroom, as the body adjusts. Some individuals may also experience temporary energy fluctuations. Meat is a readily available source of protein and iron, and unless a proper replacement is planned, a person may feel tired or weak initially. Careful planning of protein and iron-rich plant sources is crucial during this transition.

Long-Term Health Benefits of a Meat-Free Diet

Over time, numerous health benefits associated with a meat-free diet become more evident. Studies consistently link plant-based eating to a reduced risk of chronic diseases. For instance, a 2017 study found that people following a healthy, plant-based diet had a significantly lower risk of developing heart disease. This is often attributed to lower intake of saturated fats and cholesterol and higher intake of anti-inflammatory compounds found in plants.

Notable health advantages include:

Lower Cholesterol Levels: Plant-based diets are low in saturated fat, which can lead to significant drops in blood cholesterol, a key risk factor for heart disease.
Reduced Risk of Type 2 Diabetes: Multiple studies have found that plant-based diets are associated with a lower risk of developing type 2 diabetes, partly due to lower body weight and improved blood sugar management.
Lower Cancer Risk: Research has shown that a plant-based diet may reduce the risk of certain cancers, including those of the digestive system.
Better Weight Management: The high fiber content in plant foods can increase feelings of fullness, helping with weight loss and long-term weight management.

Addressing Potential Nutritional Deficiencies

While a meat-free diet offers many health benefits, a poorly planned one can lead to nutrient deficiencies. Individuals who do not eat meat must pay close attention to ensure adequate intake of several key nutrients.

Essential nutrients that require attention:

Vitamin B12: Found naturally only in animal products, B12 is critical for nerve and blood cell health. Vegans, in particular, must rely on fortified foods or supplements to meet their needs.
Iron: While many plant foods contain iron, the non-heme iron from plant sources is less easily absorbed by the body. Vegetarians and vegans, especially women, must be mindful of consuming iron-rich plant foods with Vitamin C to increase absorption.
Zinc: Zinc from plant sources is also less bioavailable. Soaking legumes and grains can help improve absorption.
Calcium and Vitamin D: Vegans need to consume fortified plant milks and leafy greens for calcium and may require a supplement for Vitamin D, as sun exposure is an unreliable source.
Omega-3 Fatty Acids: Primarily found in oily fish, vegans often have lower levels of EPA and DHA and should include sources like flaxseed, walnuts, and algae-based supplements.

Comparison: Meat-Eater vs. Vegetarian Diet


Feature	Meat-Eater's Diet	Vegetarian/Vegan Diet
Saturated Fat & Cholesterol	Typically higher intake	Typically lower intake
Fiber	Often lower intake	High intake, aids digestion
Nutrient Gaps	Less risk of B12 deficiency; can be deficient in fiber, Vitamin D, and calcium	Potential for deficiencies in B12, Iron, Zinc, Calcium, Vitamin D, Omega-3s
Gut Microbiome	Can promote bacteria linked to inflammation	Promotes healthy, fiber-digesting bacteria
Chronic Disease Risk	Higher risk for heart disease, certain cancers, and diabetes with high red/processed meat consumption	Lower risk for heart disease, Type 2 diabetes, and certain cancers
Environmental Impact	Generally higher carbon footprint, land use, and water consumption	Significantly lower environmental impact

How to Build a Balanced Meat-Free Diet

For those who don't eat meat, a well-planned diet is essential to prevent nutritional shortfalls. It involves replacing meat with a variety of nutritious plant-based alternatives and incorporating fortified foods and supplements where necessary.

Plant-based strategies for a balanced diet:

Prioritize Protein Variety: Get protein from multiple sources throughout the day, including legumes (lentils, beans), soy products (tofu, tempeh, edamame), nuts, seeds, and whole grains.
Maximize Iron Absorption: Pair iron-rich foods like lentils, spinach, and fortified cereals with Vitamin C-rich foods such as bell peppers, citrus fruits, and broccoli.
Secure B12 Intake: Regularly consume foods fortified with Vitamin B12, like nutritional yeast, certain plant milks, and breakfast cereals. A B12 supplement is often recommended.
Boost Calcium and Vitamin D: Incorporate calcium-set tofu, leafy greens, and fortified plant-based milks into your diet. Consider a Vitamin D supplement, especially with limited sun exposure.
Include Healthy Fats: Add sources of Omega-3s like flaxseed oil, walnuts, and chia seeds. Algae oil is a good direct source of EPA and DHA for vegans.

Conclusion

For a person who doesn't eat meat, the outcome is not a simple matter of losing or gaining health, but rather a transition to a different set of dietary needs and considerations. The potential health benefits—including a lower risk of heart disease and diabetes—are substantial, provided the diet is planned appropriately. The key to a successful, meat-free lifestyle lies in informed choices, proactive meal planning, and addressing potential nutrient gaps through a varied diet, fortified foods, and supplementation. A shift away from meat can be a rewarding path toward better health and a lower environmental footprint, but only if undertaken with knowledge and attention to nutritional balance.

Visit this resource for more in-depth information on nutrient intake in plant-based diets.

Frequently Asked Questions

Meat-free protein comes from a wide variety of plant sources, including legumes (beans, lentils, peas), soy products (tofu, tempeh), nuts, seeds, and whole grains. By consuming a diverse range of these foods, it is possible to meet daily protein requirements.

No. While plant-based diets are often associated with health benefits, a diet free of meat can be unhealthy if it relies heavily on processed foods, refined grains, and sugary drinks. A focus on whole, unprocessed plant foods is key for good health.

Vegans require a reliable source of Vitamin B12, usually through fortified foods or a supplement, as it is only found naturally in animal products. Depending on their diet, some vegetarians and vegans may also need to supplement for nutrients like Vitamin D, iron, and Omega-3s.

Many people experience weight loss when they stop eating meat, especially when they replace meat with high-fiber, low-calorie plant foods. The increased fiber helps you feel full longer. However, weight loss depends on overall calorie intake and the quality of the diet.

A vegetarian diet excludes meat, poultry, and fish. A vegan diet is stricter, excluding all animal products, including dairy, eggs, and honey. Veganism often extends beyond diet to exclude animal products in clothing or cosmetics.

It is possible, but it requires careful attention. Plant-based iron (non-heme) is less readily absorbed. To maximize absorption, pair iron-rich plant foods like lentils and spinach with a source of Vitamin C. Avoiding tea and coffee during mealtimes also helps.

Typically, blood cholesterol levels fall significantly after eliminating meat. This is because plant-based diets are very low in or free of saturated fat and cholesterol, which are major contributors to high cholesterol in meat-inclusive diets.