The Effectiveness of Vegan vs. High-Protein Animal-Based Diets in Managing and Preventing Obesity: A Comparative Review of Scientific Journals (2015–2024)

Abstract

Obesity is a universal health issue and finding effective dietary interventions is crucial. This

paper examines the vegan diet and high protein, animal-based diet in the management, and

prevention of obesity.

Both diet patterns can lead to weight loss by different means, but the high fiber approach has

more benefits with, likely fewer risks to health, and only if of course well-planned. Additionally,

levels of long-term adherence will come into play in both diet patterns, and therefore motivations

to change dietary behaviors to find an approach that can be maintained for a prolonged period

while providing a nutritionally adequate diet are of genuine importance.

1. Introduction

Obesity is a global phenomenon, and black hole that is a major factor in chronic disease,

specifically Type 2 diabetes and cardiovascular disease. Sustainable dietary approaches are an

important component to both managing obesity, and preventing and reducing the ingrained

increase in obesity prevalence. This paper is a brief, evidence informed critical comparison of

vegan diets, and high protein, animal-based diet patterns, including the carnivore diet, in their

features and individual mechanics, and evidence to support the management and or prevention of

obesity.

2. Methods

This review of literature incorporates systematic reviews, meta-analyses, and randomized

controlled trials (RCTs) of vegan diets compared to high-protein (including carnivore), animal-

based diets on managing and preventing obesity. This review examines how these diets impact

not only body weight, body composition, and cardiometabolic markers, but also how they impact

the gut microbiome, while also considering the relevant concerns of nutritional adequacy and

long-term sustainability/utilization for the obese individual.

2.1

Dietary Definitions: Vegan Diet: Foods consisting of plant-derived foods only (vegetables,

grains, nuts and fruits) with no animal products (meat, poultry, fish, dairy and dairy products,

eggs, honey). It is considered to be high carbohydrate and fiber, moderately high protein, and

low total fat. In comparison, a high-protein, animal-based diet may have a macronutrient

distribution that resembles 20-40% protein, 60-80% fat, and <5% carbohydrates.

2.2

Data were extracted from scientific articles (n=100) with primary literature being meta-analyses

and systematic reviews of RCT's, and/or observational studies. The primary outcome measures

were body weight, BMI, fat mass, and lean mass measures; along with cardiometabolic markers

(HbA1c, cholesterol, blood pressure, etc.).

High-Protein, Animal-based Diet: Mostly refers to being mostly animal based, with a focus on

protein consumption. May have macronutrient distributions that resemble 20-40% protein, 60-

80% fat, and <5% carbohydrates causing a positive association of animal protein consumption

with obesity risk

Data Collection and Analysis: Data from scientific articles, including both meta-analyses and

systematic reviews of RCTs and observational studies, were collected. The main outcome

measures were change in body weight, BMI, fat mass, and lean mass, as well as a number of

cardiometabolic markers (HbA1c, cholesterol, blood pressure, etc.). The synthesis was to inform

evident trends and an assessment of differences between dietary approaches.

Ethical Considerations: This paper is ethically sound by providing an accurate and objective

account of existing research in accordance with ethical guidelines related to providing accurate

views of the data, no contrived data or intentionally untrue statements were revealed. All sources

were cited appropriately, and the work is original from the work of the research material. The

analysis recognized and reported limitations of the included studies which are compatible with

participants possibly having biases regarding self-reported data and that not all observational

studies are not able to conclude cause and effect since they are cross-sectional.

3. Results

3.1. Vegan Diets and Outcomes for Weight

Vegan diets cause substantial reductions in body weight and BMI. Meta-analyses of randomized

controlled trials in healthy adults showed an average weight loss of 2.52 kg from a vegan diet,

with a 4.10 kg average weight loss for individuals with overweight, obesity, or type 2 diabetes

and a mean reduction in BMI of 1.38 kg/m² . In observational studies, mean BMIs were

significantly lower in vegans compared to omnivores. These effects of vegans on weight and

metabolism are likely due to the high fiber content of vegan diets. High fiber diets increase

satiety and lower energy density, thereby decreasing total caloric intake .

Beyond weight, vegan diets are shown to improve cardiometabolic health, with improvements in

insulin sensitivity (including HOMA-IR and fasting insulin), HbA1c in adults with

overweight/obesity, or type 2 diabetes . Vegan diets also consistently have lower total and LDL

cholesterol. While vegan diets have been shown to be nutritionally adequate, sometimes this

means carefully planning a vegan diet prior to implementation , so among other nutrients, we

want plausible attention paid to vitamin B12, vitamin D, iodine, selenium, calcium, and IRON,

as clinical evidence can allow for fortification or supplementation of these nutrients in vegans

diets .

3.2. High-Protein Animal-Based Diets and Weight Loss

High-protein animal-based diets (the carnivore diet) have been shown to be effective for short-

term weight loss and fat mass. Meta-analysis of the carnivore diet in athletes showed that the

average fat loss in the studies was 3.73% and weight loss was 4.57kg, with muscle mass

outcomes either stable or slightly decreased (the average for all of the studies that were included

in the meta-analysis was -0.33% for muscle mass). High-protein diets have higher satiety than

higher carbohydrate diets (due to the thermogenic component associated with protein and the

effects on appetite hormones, which lead to a lower caloric intake ). Long-term weight loss

maintenance has been more difficult to gauge as studies have reported gains in weight at 12

months. The cardiometabolic effects of these diets are mixed, but improvements in triglycerides

and blood pressure were noted . There are concerns about high saturated fat and sodium in these

diets contributing to lower LDL cholesterol and potentially increasing the risk for cardiovascular

disease in a few groups (especially red/processed meats). Observational studies consistently

show an increased risk of global and abdominal obesity due to higher intake of animal protein,

from meat, fish, and shellfish. Beyond the effects for obesity, high-protein animal-based diets are

deficient in dietary fiber

4 Discussion

Vegan and high protein, animal-based diets support weight loss in different means and different

possible long-term health implications. Vegan diets benefit from a lower energy density, a higher

fiber profile, and the beneficial effects on the gut microbiome that promote satiety and better

metabolic efficiency. One consequence of pursuing a vegan diet is naturally limited caloric

intake, and the associated weight loss is more likely to stick due to the substantial improvements

in cardiometabolic health that accompany vegan eating.

High protein, animal-based diets take advantage of the satiating and thermogenic effects of

protein. High protein, animal-based diets may help with short-term fat loss and preserving

muscle mass (especially when coupled with some form of resistance exercise) but have serious

challenges for long-term adherence and nutrition completeness in the format of a high protein,

animal-based diet. Possible consequences include fiber deficiency and gut dysbiosis and higher

contributions of saturated fat common in certain animal products may have harm on

cardiovascular health. There are also some observational data suggesting a positive association

of animal protein consumption with obesity risk.

For research, methodological limitations complicate interpretations including: short study

timeframes, difficulty adhering to dietary protocols in free-living conditions and large or vague

dietary definitions for the comparison groups, which make direct comparisons and longer

conclusions difficult. For any kind of dietary change, the quality of food in the quality categories

is important. A diet that emphasizes whole foods and healthy plant foods in contrast to processed

whole foods, whether vegan or animal-based will have very different results.

5. Conclusion

Both vegan and high-protein animal-based diets can result in weight loss but a well-structured

vegan diet featuring whole, unprocessed plant foods has unique benefits — offering assistance

with calorie control, carbohydrate quality, healthy gut, sustainable obesity prevention, and

subsequent health outcomes. The multiple qualities lead to significant benefits for

cardiometabolic health and gut health. High protein, animal-based diets, on the other hand, may

be used as a tool for short-term weight loss (preferably under supervision) that adds a vital

perspective on dietary habits, if you're careful in consuming lean, unprocessed proteins and pay

close attention to nutrients always being complete by supplementation where necessary.

Considering some kind of diet for obesity management, there is no question it has to be a diet

that you can be consistent long-term, meets nutritional adequacy, and other healthy lifestyle

considerations. Research going forward needs to focus on long-term, comparative studies,

explore the unique effects of varying sources of protein, explore the interactions between diets

and microbiome and metabolism, and develop strategies for long-term adherence to dietary

regimes.

6 References

Kahleova, Hana, et al. "Effects of vegan diets on cardiometabolic health: A systematic review

and meta‐analysis of randomized controlled trials." Journal of the American Heart Association,

27 Apr. 2022, PMC9540559.

"The Effect of the Carnivore Diet Under Calorie Restriction on Body Composition Changes in

Athletes: A Systematic Meta-Analysis." ResearchGate, 12 Sep. 2024.

"How to Follow a Balanced Macro Vegan Diet." Coach My Macros.

"Assessing the Nutrient Composition of a Carnivore Diet: A Descriptive Study." Nutrients, 2024.

"How Protein Can Help You Lose Weight." Healthline.

"Plant-Based Diets: A Review of Their Impact on Body Composition and Cardiometabolic

Health." Journal of the American College of Cardiology, 26 Nov. 2019.

"The potential impact of animal protein intake on global and abdominal obesity: Evidence from

the Observation of Cardiovascular Risk Factors in Luxembourg (ORISCAV-LUX) study."

Public Health Nutrition, 22 Jan. 2015.

"The Carnivore Diet: