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The Impact of BMI on Health Markers in Different Dietary Groups: Vegetarians vs. Omnivores

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When it comes to choosing a diet, most people juggle between the many options available, each claiming its own set of benefits. In this article, we dissect the findings of a recent study that examined the association between BMI increase in 1340 individuals with different dietary groups and biochemical markers. Spoiler alert: There are some intriguing revelations about the potential advantages of vegetarian diets in obesity-related morbidities.

Study Background and Population

The study analyzed a sample of 1340 individuals aged 18-60 from a private clinic in São Paulo, Brazil. Participants were classified into four dietary groups: omnivores, semi-vegetarians, lacto-ovo-vegetarians, and vegans.

Key Health Markers Analyzed

The markers evaluated in the study include hs-CRP, liver enzymes (ALT, AST, GGT), ferritin, glucose profile, and HbA1C. Linear models, regression models, and chi-square tests were used to analyze the data and assess the impact of different diets on these health markers.

Findings: The Impact of BMI and Dietary Groups

The study found that omnivorous men and women have a higher prevalence of obesity, while vegan women are more likely to be underweight. Increased BMI was associated with worse metabolism across all dietary groups. Interestingly, obese vegetarians displayed better antioxidant status (lower GGT elevation) and lower inflammatory status (lower ferritin elevation) compared to their omnivorous counterparts.

The Benefits of a Vegetarian Diet in Obesity

The findings suggest that a vegetarian diet may offer potential protection against morbidities associated with excess weight. Obese vegetarians showed lower ferritin and GGT levels. High levels of these two substances are associated with metabolic syndrome and its consequences, as cardiovascular disease and diabetes. This could be attributed to the increased antioxidant content and potentially lower levels of xenobiotics in vegetarian diets.

Limitations and Future Research

The study did not assess details of food consumption or microbiota composition, which could provide further insight into the mechanisms behind the observed benefits of vegetarian diets in obesity-related morbidities. Future research could explore these factors and further investigate the effects of different dietary patterns on health markers in larger and more diverse populations.


This study highlights the potential benefits of a vegetarian diet in obesity-related morbidities. While increased BMI values were associated with worse metabolic conditions across all dietary groups, obese vegetarians displayed better antioxidant and lower inflammatory status, which may provide potential protection against weight-related health complications.

Based on biochemical exams analyzed, all individuals (regardless of their chosen diet) experience a decline in their health status. Interestingly, obese individuals who follow a vegetarian diet demonstrated a lower increase in harmful parameters measured, when compared to those who follow an omnivorous diet. These findings shed light on the potential health benefits of a vegetarian diet, particularly for those struggling with obesity. However, it is important to note that all individuals in the study experienced a decline in health, highlighting the need for continued research and education around healthy dietary choices.

This post is based on the original academic paper authored by Dr. Eric Slywitch, who serves as the Coordinator of the Nutrition Department at the International Vegetarian Union.

Source: Pubmed

Download the Paper File:
pdf Obese Vegetarians and Omnivores Show Different Metabolic (2.34 MB)
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