I'm not a vegetarian but the implication of claims in this thread appears to be that vegetarianism or veganism makes you fat and unhealthy. In fact, the opposite is the case.
Several epidemiological studies have examined differences in body weight based on dietary patterns. These patterns include vegan, vegetarian (veg), pesco-vegetarian (pesco-veg), semi-vegetarian (semi-veg), or omnivorous (omni) diets.[11] Data from the Adventist Health Study (AHS) have shown that BMI increases as the amount of animal foods in the diet increases, such that vegans had the lowest BMI, followed by veg, pesco-veg, semi-veg, and omni diets.[11] Moreover, findings from the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford) study, have shown that vegans gain significantly less weight as they age compared to omnivores.[12] Converting to a more plant-based diet also appears to be protective against weight gain, as does following a pesco-veg diet for women.[12] The EPIC-PANACEA study, an off-shoot of the EPIC-Oxford study, found a positive association between total meat consumption and weight gain, even after adjusting for energy intake: an increase in 250 g/day of meat led to a 2 kg weight gain after 5 years (95% CI: 1.5–2.7 kg).[13]
Along with the findings from the two large AHS and EPIC studies, the Swedish Mammography Cohort found that omnivores had the highest prevalence of overweight and obesity compared to individuals following dietary patterns with less meat.[14] In a study examining a cohort of 49,098 Taiwanese adults, the percentage of participants with a BMI ≥ 27 kg/m2 was significantly lower among those following a vegetarian diet (10.9%) as compared to those following a non-vegetarian diet (15.4%). Additionally, this study also found that for every year on a vegan diet, the risk of obesity decreased by 7% (95% CI: 0.88–0.99).[15]
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5466943/
Animal products contain much more fat than plant-based foods. Because vegetarian diets are the only diets that work for long-term weight loss, it’s no surprise that population studies show that meat-eaters have three times the obesity rate of vegetarians and nine times the obesity rate of vegans. It’s possible to be an overweight or obese vegan, of course, just as it’s possible to be a thin meat-eater, but adult vegans are, on average, 10 to 20 pounds lighter than adult meat-eaters.
Adopting a vegan diet won’t just help you slim down, it will also help you fight an array of ailments, including heart disease, diabetes, arthritis, and cancer. Dr. T. Colin Campbell of Cornell University, arguably the foremost epidemiologist in the world, states, “Quite simply, the more you substitute plant foods for animal foods, the healthier you are likely to be. I now consider veganism to be the ideal diet. A vegan diet—particularly one that is low in fat—will substantially reduce disease risks. Plus, we’ve seen no disadvantages from veganism. In every respect, vegans appear to enjoy equal or better health in comparison to both vegetarians and non-vegetarians.”
https://www.peta.org/issues/animals-used-for-food/obesity/