Plant-Based Diets: Vegan, Vegetarian and Flexitarian

The short version

Plant-based is a spectrum, from flexitarian (mostly plants) to vegan (no animal products).
People who eat this way tend to weigh less and have lower cholesterol, largely thanks to fiber and fewer calories.
Vegan fries and cookies still count as junk food. Base your meals on whole plants.
Vegans need a B12 supplement or fortified foods. Some other nutrients also take planning.

In a sentence: Mostly or only plants, from flexitarian to fully vegan.
How restrictive
Counting needed?: No
Quality of evidence: Moderate
Typical cost: Low to moderate
Main drawback: Needs planning for B12, iron, omega-3s and protein

See how this compares with every other diet →

The spectrum

Style	What it leaves out
Flexitarian	Nothing fully. Mostly plants, with meat occasionally
Pescatarian	Meat and poultry, but keeps fish
Vegetarian	Meat, poultry and fish, but usually keeps eggs and dairy
Vegan	All animal products

What the evidence says

Weight. On average, vegetarians and vegans weigh less than people who eat meat, and short trials suggest that switching can lead to weight loss even without counting calories. Plant-based meals tend to be high in fiber and water and lower in calorie density, so you feel full on fewer calories. Long-term trial data is thinner, and part of the difference in population studies may come from other healthy habits.

Heart health. Plant-forward patterns usually lower LDL cholesterol. Major heart organizations support them, as long as they're built on whole foods.

Quality matters. There's a big difference between lentils and vegetables, and meat-free fries and sugary cereal. Studies consistently separate these, and an unhealthy plant-based diet doesn't bring the same benefits.

Nutrients to plan for

Vitamin B12: Found naturally only in animal foods. Vegans need a supplement or fortified foods. A deficiency can cause nerve damage, and it can be slow to show up.
Iron: Plant iron is absorbed less well. Pair beans and greens with vitamin C, such as peppers, citrus or tomatoes.
Calcium and vitamin D: Try fortified plant milks, tofu made with calcium and leafy greens.
Omega-3s: Ground flax, chia and walnuts, and consider an algae-based supplement.
Iodine and zinc: Use iodized salt, beans, seeds and whole grains.
Protein: Very doable, but plan it. Tofu, tempeh, edamame, lentils, beans, seitan and plain soy milk are your friends. See protein.

How to start

Try one or two meat-free dinners a week.
Start with familiar meals, like bean chili, lentil tacos, veggie stir-fry with tofu, or pasta with white beans.
Keep canned beans, frozen vegetables and whole grains on hand. It's one of the cheapest ways to eat.
Go slowly on beans and fiber if your gut isn't used to them. See fiber.

Pros and cons

Good: Inexpensive at its core, high in fiber and good for your cholesterol.

Harder: Eating out and family dinners can be tricky, and strict versions need planning. It's also easy to overeat refined carbs when you first drop meat.

Sources

This guide is general information, not medical advice. Please check with a clinician before making big changes, especially if you have a health condition, take medication, or are pregnant. Read the full disclaimer.