Flexitarian Diets After Bariatric Surgery

After Bariatric Surgery

For individuals considering or recovering from bariatric surgery, diet is just as important as the procedure itself. While plant-based eating has been linked to better health outcomes, not everyone is ready, or needs, to give up meat entirely. That’s where the flexitarian diet comes in: a mostly vegetarian approach that still leaves room for occasional meat or fish.

Flexible, sustainable, and increasingly supported by research, this eating style may offer significant health benefits, particularly for those seeking to manage weight, support metabolic health, and maintain nourishment after surgery.

What Is a Flexitarian Diet?

The term “flexitarian” merges “flexible” and “vegetarian.” It describes someone who eats a predominantly plant-based diet but occasionally includes meat or fish. Some definitions use “semi-vegetarian” or “demi-vegetarian” interchangeably, usually indicating a person who eats meat fewer than three times per week. The emphasis is on reducing, not eliminating, animal products while increasing fruits, vegetables, whole grains, legumes, and plant-based fats.¹

This approach provides a practical path for many individuals who aren’t yet ready to commit to a vegetarian lifestyle but want to make more health-conscious food choices. Nearly 30% of people in Britain report having reduced their meat intake, with health concerns cited as a top reason.¹

Flexitarian Diets and Weight Control

Multiple studies have shown a strong association between reduced meat intake and a healthier body weight. Extensive cross-sectional studies indicate a trend where BMI tends to increase in conjunction with the frequency of meat consumption. (Although the type of meat consumed is not clear, including items like processed or grass-fed meat.) Vegans had the lowest average BMI, while flexitarians fell in the middle, lower than non-vegetarians but higher than strict vegetarians.^1-2

One Korean study followed postmenopausal women who had maintained a semi-vegetarian diet for 20 years and found they had significantly lower body weight, BMI, and body fat percentage than non-vegetarians.³ Another longitudinal survey showed that those eating semi-vegetarian diets consumed the fewest calories – around 1,713 calories per day – compared to other dietary groups.³ These findings suggest that flexitarian diets can be effective for long-term weight management, especially in populations prone to weight gain or weight regain.

That said, motivations matter. Research also shows that people who identify weight control as their main reason for becoming flexitarian may be more prone to “restrained eating” – a pattern of dieting that can lead to cycles of overeating and emotional distress.⁴ This highlights the importance of working with a healthcare provider or dietitian to make sure food choices are driven by health, not by guilt or pressure.

Other Health Benefits

Flexitarian diets are associated with a lower BMI and appear to improve several markers of metabolic health. The same postmenopausal women who followed a semi-vegetarian diet for over 20 years showed significantly better glucose levels, lower insulin resistance, and healthier lipid profiles.⁵ Other extensive studies found lower rates of type 2 diabetes and metabolic syndrome among flexitarian eaters compared to meat-eaters.

In some smaller studies, flexitarian diets have been associated with reduced blood pressure and potential benefits for inflammatory bowel diseases, such as Crohn’s disease; however, more research is needed to confirm these mechanisms.⁵

Because flexitarian diets emphasize plant-based foods, they also tend to be rich in fiber and lower in saturated fat, both of which are key for heart and gut health. However, nutrient gaps can still occur, especially if the diet isn’t well-planned. For instance, semi-vegetarians have been shown to have higher rates of iron deficiency compared to omnivores, and omega-3 intake can be lower if fish is excluded too often.

How to Follow a Flexitarian Diet the Healthy Way

If you’re using a flexitarian diet to support weight loss, maintain bariatric outcomes, or improve overall health, quality and balance are essential. Here are some tips for making it work:

Plan plant-forward meals with protein sources such as legumes, tofu, tempeh, eggs, and occasionally fish or poultry.
Include iron-rich foods, such as lentils, leafy greens, and fortified grains, paired with vitamin C sources like citrus, for improved absorption.
Choose whole foods over highly processed meat substitutes, which can be high in sodium or additives.
Add variety with beans, peas, whole grains, nuts, seeds, and colorful vegetables to maximize nutrient density.
Watch your motivation. If the goal is to support health, not just control weight, you’re more likely to build sustainable habits and avoid disordered eating patterns.
Aim for half your plate to be filled with vegetables, a quarter with whole grains, and a quarter with protein.
Batch cook staples like brown rice, roasted vegetables, and bean-based soups to mix and match throughout the week.
Rotate in lean meats or fish a few times a week, keeping portions modest and pairing with fiber-rich sides to promote satiety.

Focus on meals that are satisfying, easy to prepare, and aligned with your goals. Don’t hesitate to ask a dietitian for help tailoring the diet to your specific nutritional needs. Here are some simple, nutrient-dense ideas to get you started:

A grain bowl with quinoa, roasted chickpeas, avocado, and tahini dressing
Stir-fried tofu with broccoli, snap peas, and brown rice
Lentil or white bean soup with a slice of whole grain bread
A veggie-packed omelet with a side of fruit
Grilled salmon tacos with cabbage slaw and black beans

It may seem overwhelming to overhaul your diet, but you can keep it simple while also enjoying a satisfying meal.

The Bottom Line

Flexitarian diets can offer a sustainable and approachable way to reduce meat intake without eliminating it. When done mindfully, it can help support long-term weight control, better metabolic health, and overall well-being.

For patients recovering from or preparing for bariatric surgery, a flexitarian approach can support progress without adding dietary overwhelm. Still, as with any eating plan, personalization and professional guidance make all the difference. Whether you’re planning surgery or are recovering, stay in touch with the team at Higa Bariatrics for ongoing dietary support.

Derbyshire E. J. (2017). Flexitarian Diets and Health: A Review of the Evidence-Based Literature. Frontiers in nutrition, 3, 55. https://doi.org/10.3389/fnut.2016.00055.
Forestell C. A. (2018). Flexitarian Diet and Weight Control: Healthy or Risky Eating Behavior?. Frontiers in nutrition, 5, 59. https://doi.org/10.3389/fnut.2018.00059.
Derbyshire E. J. (2017). Flexitarian Diets and Health: A Review of the Evidence-Based Literature. Frontiers in nutrition, 3, 55. https://doi.org/10.3389/fnut.2016.00055.
Forestell C. A. (2018). Flexitarian Diet and Weight Control: Healthy or Risky Eating Behavior?. Frontiers in nutrition, 5, 59. https://doi.org/10.3389/fnut.2018.00059.
Derbyshire E. J. (2017). Flexitarian Diets and Health: A Review of the Evidence-Based Literature. Frontiers in nutrition, 3, 55. https://doi.org/10.3389/fnut.2016.00055.