A flexitarian is someone who eats a mostly plant-based diet but still includes meat, fish, eggs, or dairy occasionally. Think of it as vegetarianism with built-in wiggle room. About 37% of U.S. adults already eat this way, making it one of the most common dietary patterns in the country, even if many people don’t use the label.
Where the Term Comes From
The word “flexitarian” blends “flexible” and “vegetarian.” It appeared in popular media in the early 2000s but didn’t gain real traction until 2010, when registered dietitian Dawn Jackson Blatner published The Flexitarian Diet. Blatner described the approach as “casual vegetarian” eating: mostly plants, with the freedom to have a burger or grilled chicken when you want one. The formal nutritional definition is narrower than most people realize. Researchers define a flexitarian as someone who eats at least one animal product per month but less than once per week.
The Three Levels
Blatner’s original framework lays out three tiers based on how many meatless days you hit each week:
- Beginner: Two meatless days per week
- Advanced: Meat on only three or four days per week
- Expert: Meat on just two days per week (five meatless days)
There’s no rigid meal plan or calorie counting involved. The core idea is simply shifting the balance of your plate toward vegetables, legumes, whole grains, nuts, and fruits while treating meat as an occasional ingredient rather than the centerpiece of every meal.
Heart and Metabolic Health
Cutting back on meat, even without eliminating it, appears to move several cardiovascular risk markers in a favorable direction. A cross-sectional study comparing flexitarians (eating no more than about 50 grams of meat per day), vegans, and heavy meat eaters found that flexitarians and vegans both had better insulin levels, triglycerides, total cholesterol, and LDL cholesterol than omnivores. Flexitarians actually showed the most favorable scores for metabolic syndrome risk, based on both BMI and waist measurements, and had better arterial stiffness readings than both vegans and omnivores.
Diabetes risk follows a similar pattern. The Adventist Health Study 2, which tracked nearly 61,000 people, found that type 2 diabetes prevalence dropped in a stepwise fashion as animal product consumption decreased: 7.6% in regular meat eaters, 6.1% in semi-vegetarians, 4.8% in those who ate only fish, 3.2% in lacto-ovo vegetarians, and 2.9% in vegans. Semi-vegetarians had a 24% lower risk of type 2 diabetes compared to non-vegetarians. You don’t have to go fully plant-based to see a measurable benefit.
Weight and Body Composition
People who eat a flexitarian pattern tend to carry less body weight and body fat than those eating a standard omnivore diet. Long-term data from a Korean study of postmenopausal women found that those who maintained a semi-vegetarian diet for 20 years had significantly lower body weight, BMI, and body fat percentage than non-vegetarians. The effect likely comes from the higher fiber and lower calorie density of plant-heavy meals. When vegetables, beans, and whole grains fill most of your plate, you naturally eat fewer calories without needing to track them.
Environmental Impact
One of the reasons the flexitarian label has gained so much ground is its environmental angle. A New Zealand study calculated greenhouse gas emissions across four diet patterns and found striking differences. A typical household diet produced 597 kg of CO2 equivalent, while a flexitarian diet produced 263 kg, a reduction of more than 55%. A vegan diet was lower still at 203 kg, but the jump from a standard diet to flexitarian captured the majority of the climate benefit.
For people who want to shrink their food-related carbon footprint but find veganism impractical, flexitarianism delivers most of the environmental gain with considerably less restriction.
What It Costs
A common assumption is that eating more plants and less meat costs more. The data suggests the opposite. A study of Portuguese consumers found that omnivores spent the most on groceries at roughly €76 per week, while flexitarians spent about €69 per week. Vegans spent the least at €48. Meat, particularly beef, is one of the most expensive items in a grocery basket, so replacing several meat-centered meals per week with beans, lentils, tofu, or eggs tends to lower the overall bill.
Nutrients to Watch
The flexibility that makes this diet approachable also creates a blind spot. Because flexitarians still eat some animal products, many assume they’re getting all the nutrients they need. The reality is more nuanced.
Vitamin B12 is the most notable gap. A pilot study found that flexitarians’ average B12 intake was about half the recommended amount, and 13% showed signs of B12 undersupply. That rate was actually higher than in vegans (9%), likely because vegans are more aware of the risk and supplement accordingly. Only about 30% of flexitarians in the study used any supplements, compared to over 80% of vegans.
Vitamin D is another concern. More than half of flexitarians in the same study had insufficient or deficient vitamin D levels, a higher rate than both vegans and omnivores. Iron is worth watching too, especially for women. Among women in the study, 67% of flexitarians showed early signs of iron depletion, compared to 61% of vegans and 54% of omnivores.
The takeaway isn’t that flexitarian eating is risky. It’s that reducing meat without intentionally replacing the nutrients meat provides can leave gaps. A B12 supplement, attention to iron-rich plant foods like lentils and spinach, and adequate vitamin D (from sunlight, fortified foods, or a supplement) close those gaps easily.
What a Typical Week Looks Like
There’s no single “right” way to eat flexitarian, which is part of the appeal. Some people designate specific meatless days (Meatless Monday through Wednesday, for example). Others simply default to plant-based meals and add meat only when they’re actively craving it or eating out. A typical week for someone at the advanced level might include oatmeal with nuts and fruit for breakfast most days, grain bowls or bean-based soups for lunch, and dinner built around vegetables and legumes four or five nights, with chicken, fish, or red meat on the remaining evenings.
The foods that do the heavy lifting are beans, lentils, chickpeas, tofu, tempeh, eggs, whole grains, nuts, seeds, and a wide variety of vegetables and fruits. Dairy can fill in where it fits. When meat does appear, the portion tends to be smaller, more like a side or flavor accent than the main event.
For most people, the shift happens gradually. Starting with two meatless days a week is enough to qualify as a beginner flexitarian, and many find that as they discover plant-based meals they genuinely enjoy, the ratio keeps tilting on its own.