Flexitarian Diet
Mostly plant-based, with meat as an occasional addition rather than a daily staple.
Not to be confused with Flexible Dieting (IIFYM) elsewhere on this page — that one is about hitting macro targets with any foods; this one is about a plant-forward food pattern with occasional meat.
How It Works
"Flexitarian" — a blend of "flexible" and "vegetarian" — was coined by registered dietitian Dawn Jackson Blatner in her 2009 book The Flexitarian Diet: The Mostly Vegetarian Way to Lose Weight, Be Healthier, Prevent Disease, and Add Years to Your Life (McGraw-Hill). It isn't a rigid rulebook: most meals are built around vegetables, fruit, whole grains, and plant protein (beans, lentils, tofu), with meat treated as an occasional addition — a few times a week rather than a daily default — instead of being eliminated outright. There are no macro targets, calorie counts, or banned foods; the only real "rule" is shifting the center of gravity of your plate toward plants most of the time.
The Research
Most research on plant-forward eating studies "vegetarian" or "vegan" patterns broadly. What's more directly relevant to flexitarian eating is research that specifically separates out a semi-vegetarian category — people who eat meat, just less than once a week — from both stricter vegetarian patterns and regular meat-eating. That's a closer match to how flexitarian eating actually works in practice, and it's worth knowing the semi-vegetarian pattern shows real but more modest benefits than full vegetarian or vegan patterns, not an equivalent effect.
Type 2 diabetes: Tonstad S, Butler T, Yan R, Fraser GE. "Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes," Diabetes Care, 2009. In roughly 61,000 adults from the Adventist Health Study-2, split into five groups by how much meat they ate, type 2 diabetes prevalence was 2.9% in vegans, 3.2% in lacto-ovo vegetarians, 4.8% in pesco-vegetarians, 6.1% in semi-vegetarians (meat less than once a week), and 7.6% in regular meat-eaters — the semi-vegetarian group sat consistently between the stricter plant-based patterns and the non-vegetarian group, not matching either one.Read the study →
Mortality: Orlich MJ, Singh PN, Sabaté J, et al. "Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2," JAMA Internal Medicine, 2013 — the same large cohort (73,308 adults) cited on this site's Plant-Based & Vegan Diets page, but the number that matters here is specific to the semi-vegetarian subgroup: their all-cause mortality hazard ratio was 0.92 (95% CI 0.75–1.13) — a trend toward lower risk, but not statistically significant, unlike the larger, significant reductions seen in the vegan, lacto-ovo, and pesco-vegetarian subgroups in the same study. Worth being direct about: this specific pattern's mortality benefit, at least in this cohort, didn't clear the bar for statistical significance.
Read the cohort study →
Rankings: U.S. News & World Report's expert panel has placed Flexitarian in the top tier of its "Best Diets Overall" rankings for multiple consecutive years, and ranked it first in its "Best Plant-Based Diets" category in 2024 — worth knowing this is an expert-panel ranking based on ease of use, nutritional completeness, and safety, not a single clinical trial result.
Food Examples
Most meals: vegetables, fruit, whole grains (oats, quinoa, brown rice), legumes
(lentils, chickpeas, black beans), tofu and tempeh, nuts and seeds.
Meat, a few times a week rather than daily: a smaller portion of chicken, fish, or
beef added to an otherwise plant-based meal, rather than being the meal's main component every time.
A Sample Day
Breakfast: oatmeal with fruit and walnuts (plant-based).
Lunch: lentil-and-vegetable soup with whole-grain bread (plant-based).
Dinner: stir-fried vegetables and rice with a smaller portion of chicken or shrimp
mixed in — meat as an addition to the dish, not the center of the plate.
On other nights that same dinner slot might be entirely plant-based (tofu or beans standing in for
the meat) — there's no fixed ratio, just a general lean toward plants most of the time.
Who It Might Suit
Tends to suit people who want some of the cardiometabolic benefits associated with plant-forward eating without eliminating meat entirely — useful for shared households, social eating, or anyone who finds a full vegetarian or vegan commitment too restrictive to sustain. Given the research above, it's worth setting realistic expectations: the semi-vegetarian pattern's benefits look real but more modest than stricter plant-based patterns, so it may not suit someone specifically chasing the larger risk reductions tied to full vegetarian or vegan eating. Because it has no fixed rules, it also offers less structure than plans with explicit food lists or macro targets — which can be a feature or a drawback depending on how you respond to structure.