What is a vegetarian diet?
A vegetarian diet excludes meat and fish but includes — in its most common form — eggs and dairy products. This is called a lacto-ovo vegetarian diet and is the eating pattern most people mean when they say "vegetarian."
Historically, vegetarianism has been practiced for thousands of years in India, parts of Asia, and among religious groups such as Seventh-day Adventists. That makes the vegetarian diet one of the most studied non-omnivorous dietary patterns — with cohort studies spanning 30+ years and hundreds of thousands of participants.
The vegetarian diet has a unique advantage: it delivers most of the health benefits of a plant-based diet without the nutritional risks that come with a fully vegan diet. Eggs and dairy cover B12, complete protein, and most critical micronutrients automatically.
Types of vegetarian diets
Lacto-ovo vegetarian
The most common form. Excludes meat and fish, includes eggs and dairy. The most studied variant and the easiest to keep nutritionally balanced.
Lacto-vegetarian
Excludes meat, fish, and eggs. Includes dairy products. Common in India. B12 needs are covered by milk products.
Pescatarian
Excludes meat but includes fish, eggs, and dairy. Provides omega-3 (EPA/DHA) directly. Often the dietary pattern with the strongest evidence in cohort studies.
Flexitarian
Primarily vegetarian with occasional meat (1–2 times per week). Pragmatic and sustainable. Studies show that flexitarians gain most of the health benefits of a vegetarian diet.
What does the research say?
Lacto-ovo vegetarians had 9% lower all-cause mortality compared to omnivores. Pescatarians showed the strongest effect of any group: 19% lower mortality. Vegetarians had 62% lower risk of type 2 diabetes and significantly lower risk of hypertension and metabolic syndrome.
Vegetarians had 22% lower risk of ischemic heart disease. Overall cancer risk was lower (−14%), especially for colorectal cancer. Notably, vegetarians had a slightly higher risk of stroke (20%), possibly linked to lower B12 and omega-3 levels. The effect disappeared among those who supplemented.
Dinu et al. (Critical Reviews in Food Science, 2017) summarized 86 studies: vegetarians had significantly lower LDL cholesterol (−13%), lower BMI (−1.5 kg/m²), lower blood pressure (−5 mmHg systolic), and 25% lower risk of heart disease. The effects were consistent regardless of study design.
Where the research stands in 2026
The vegetarian diet has strong evidence from large cohort studies and meta-analyses. The level of evidence is high for cardiovascular health, diabetes, and longevity. The only weakness: the stroke risk observed in EPIC-Oxford needs further study, but is likely explained by B12/omega-3 deficiency rather than the diet itself.
Vegetarian vs. vegan — what does the evidence show?
The question is inevitable: is vegan better? The answer is nuanced.
| Factor | Vegetarian | Vegan |
|---|---|---|
| Cardiovascular protection | Strong (−22%) | Strong (−25%) |
| B12 risk | Low (eggs + dairy) | High (supplement required) |
| Omega-3 (DHA) | Low (eggs provide some) | Very low (algae oil required) |
| Protein quality | High (egg = reference protein) | Requires complementary proteins |
| Practical difficulty | Low | Medium–High |
| Carbon footprint | −50% vs. omnivore | −73% vs. omnivore |
| Fracture risk | Normal | Slightly elevated |
Bottom line: A vegetarian diet delivers 80–90% of the health benefits of a vegan diet with significantly lower risk of deficiency diseases. For most people, it is the most sustainable and practical plant-based diet. A vegan diet has marginally stronger effects — but requires more planning and knowledge.
Getting started — week by week
Week 1: Meat-free weekdays
Start with 3–4 meat-free days per week. Eggs and cheese make the transition easy: vegetable omelet, pasta with ricotta and spinach, bean chili with sour cream. Keep meat on the weekend if you like.
Weeks 2–3: Learn the legume basics
Introduce legumes as a protein source 3–4 times per week. Lentil soup (20 min), hummus (buy premade), chickpea stew (25 min), and bean salad (10 min). In practice, this is what replaces the meat.
Week 4+: Fully vegetarian
Drop the last meat. By now you already have the repertoire. Add nuts as snacks, yogurt with berries for breakfast, and whole grains as your base. Consider an omega-3 supplement (algae oil or omega-3-enriched eggs).
A day of vegetarian eating
Breakfast: Greek yogurt with blueberries, granola, and honey. Boiled egg with rye bread.
Lunch: Lentil soup with bread and a dollop of sour cream. Side salad with feta cheese.
Snack: Apple with almonds. Carrot sticks with hummus.
Dinner: Halloumi wrap with vegetables, beans, and avocado. Or pasta with pesto, broccoli, and parmesan.
Evening snack: Quark with cinnamon and walnuts.
Cipoli analysis
What does the data show about vegetarian diets and health?Here we will show a group comparison between Cipoli users who eat vegetarian versus other dietary patterns.
- 📊 Health Index comparison between groups
- 🔬 Differences in cardiovascular, inflammation, and energy markers
- 📈 Correlations with gut health and mental health
Why don't I see any data yet?
We need more responses before we can run meaningful analyses.
Your personal connection
How well do your habits match a vegetarian diet?See how close you are to a vegetarian diet
Log in and map your health to get your Vegetarian Diet Index.
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