What do vegetarian and vegan diets tell us about eating disorders?

“No thanks, I don’t eat meat.” This simple sentence can elicit very different reactions, but the question that often follows is: “Why?”

The answer may reflect interest in animals, the environment, religion, or personal health. Families and health care professionals may also wonder whether giving up meat provides a socially acceptable way to restrict food.

However, a new systematic review and meta-analysis found no clear overall difference in eating disorder symptoms between people who follow a strict vegetarian or vegan diet and people who eat meat.

A systematic review uses a structured process to identify and evaluate available evidence. A meta-analysis combines the numerical results of similar studies to estimate the general pattern.

Eating disorders can involve disturbing thoughts and behaviors about food, weight, or body shape. These may include severe restrictions, binge eating, vomiting, or excessive exercise. So removing food categories can cause anxiety. However, people adopt vegan diets for a variety of reasons, including animal welfare, religion, health, and environmental concerns. The meaning of the restriction is important.

The review collected 24 studies involving 25,223 people. Studies used specific questionnaires to assess experiences such as food restriction, loss of control while eating, and anxiety about weight or body shape. These questionnaires measured participants’ reported symptoms. They did not specify whether everyone had an eating disorder.

The researchers applied strict definitions to the diets compared. Vegetarians excluded meat, poultry, fish and seafood. Vegetarians exclude all animal-derived foods. The researchers excluded flexitarian, pescatarian and semi-vegetarian diets because they allow some meat or fish and can be followed for different reasons.

Individual results were mixed. Some studies reported more symptoms among vegetarians, some reported fewer symptoms, and others found no clear difference. When the researchers combined the results, there was no meaningful overall difference between the food groups.

Read also: Regaining weight after dieting depends on brain biology

This finding does not mean that a vegetarian diet can never coexist with an eating disorder. This means that the food label alone tells us little about a person’s mental health.

Motivation is important

Think of two people who stop eating meat. One acts out old concerns about animal welfare and remains relaxed and flexible about food. The other begins to stop eating an increasing number of foods due to the intense fear of gaining weight. What they eat may seem similar, although their reasons and experiences differ sharply.

Only a few studies in the review examined motivation. One study of college students found that people who adopted a partially vegetarian diet to manage weight reported more eating disorder symptoms. However, most studies did not record why participants followed their diet, so motivation cannot yet be used as a reliable test of risk.

He can still lead a useful conversation. Qualitative research involving people with experience of eating disorders suggests asking when dietary change began, whether it was driven by fear, whether other dietary rules emerged, and how much flexibility the person maintained.

Sudden change accompanied by weight loss, distress, secrecy, or increased restrictions may merit close attention. A long-term diet that reflects someone’s values, meets their nutritional needs and does not cause distress presents a different picture.

The evidence has several limitations. All 24 studies were cross-sectional, meaning they collected information at one point in time. They cannot show whether the dietary change occurred before eating disorder symptoms appeared or whether people who already had symptoms were more likely to become vegetarians or vegans.

Studies also provided limited information about diet quality, duration, or motivation. Most were conducted in Western countries, and relatively few included adolescents or older adults. Nearly seven out of ten participants were women, so the results are less certain for men and for other groups poorly represented in the research.

Measurement may also affect the results. Standardized questionnaires for eating disorders have been developed for a broader population. Some questions may interpret the intentional exclusion of food as unhealthy restriction even when it reflects moral or religious obligations. So researchers began developing screening questionnaires specifically designed for vegetarians. Screening tools identify people who may benefit from more comprehensive evaluation, but do not provide a diagnosis.

Concerns about an eating disorder should be taken seriously, but a vegan diet should not be treated as a warning sign in itself. A more useful assessment asks why the diet was adopted, whether it has become increasingly restrictive, whether the food causes fear or distress, and whether the person is receiving adequate nutrition.

These features reveal the potential difficulty more than the absence of meat or animal products.

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