A healthy, nutritious diet is essential for your physical and mental well-being. Long-term adherence to a vegetarian diet has shown to provide a myriad of positive health benefits, such as reduced risk of cardiovascular disease, cancer, diabetes, hypertension, obesity, and reduced mental health disorders.
Individuals who follow a mostly animal-based diet (omnivores), and want to move towards a more plant-based diet, may be wondering what the short-term benefits of adopting a vegetarian diet for a day, a week, or a month are.
In this article we explain (in plain English!) the conclusions of scientific studies that have looked at short-term vegetarianism.
Vegetarian diets consist of plant-based foods rich in whole grains, legumes, nuts, seeds, fruits, and vegetables, while avoiding red meat, processed meat products, refined foods, and sweets.
There are several variations of a vegetarian diet:
Benefits of Short-Term Vegetarianism
We have looked at numerous studies that have reported the many health benefits of following a vegetarian diet for a short period of time.
The length of time participants in these studies followed a vegetarian diet varied from 4 days to 16 weeks.
In the sections that follow we highlight studies that have linked short-term vegetarianism with health benefits such as:
Lowered Blood Pressure
A short-term vegetarian diet may lower your blood pressure.
A study published in the American Journal of Lifestyle Medicine, reported that participants following a 15-day whole-food, plant-based diet rich in vegetables, fruits, and whole grains had a significant reduction in systolic blood pressure “average systolic blood pressure drop was 6.8 points (16.8 points for those with systolic blood pressure >140)” (Friedman et al., 2021).
A study conducted by researchers from the Texas Woman’s University, evaluated the effectiveness of a 4-week raw, plant-based diet consisting of raw fruits, vegetables, seeds, and avocado on hypertension and hypercholesterolemia. Significant reductions in the systolic and diastolic measurements were observed after the 4-week period “Four weeks of a defined, plant-based dietary intervention resulted in clinically significant reductions in systolic blood pressure, diastolic blood pressure, blood pressure medication usage, total medication usage, and serum lipids” (Najjar et al., 2018).
Weight Loss and Improved Heart Health
A short-term vegetarian diet may provide a beneficial impact on your cardiovascular health and weight loss. Cardiometabolic risk factors include: obesity, hypertension, low-density lipoprotein (LDL) cholesterol, and insulin resistance.
A study published in the Journal of the American Nutrition Association, investigated the impact of adopting a vegan or Mediterranean diet for 16 weeks on health parameters such as body weight, and cardiometabolic risk factors. They found that switching to a vegan or Mediterranean diet for a 16-week period improved all health parameters “A low-fat vegan diet improved body weight, lipid concentrations, and insulin sensitivity, both from baseline and compared with a Mediterranean diet. Blood pressure decreased on both diets, more on the Mediterranean diet” (Barnard et al., 2020).
A study published in the journal, Nutrition, investigated the effect of a 12-week whole-food, plant-based diet on cardiovascular health of individuals from Montreal, Canada who had at least one risk factor of cardiovascular disease. A positive improvement in cardiovascular risk parameters such as weight, total cholesterol, and low-density lipoprotein was observed after the 12-week period “The whole-food, plant-based nutrition program improves cardiovascular health in adults” (Morin et al., 2019).
Scientists from the University of Rochester, who conducted an 8-week whole-food, plant-based lifestyle modification program on members of the community reported an improvement in body weight towards a healthier body mass index (BMI), and reduced cholesterol levels “A whole-food plant-based dietary intervention may provide significant short-term benefits for both non-vegetarian, vegetarian, and vegan individuals; participants experienced statistically significant weight loss and reductions in total and LDL cholesterol” (Campbell et al., 2019).
Scientists from the University of Oslo, investigated the effect of a 3-week vegetarian diet and fasting on patients with fibromyalgia. A 3-week vegetarian diet lead to decreased levels of peroxide and plasma fibrinogen levels – high levels of these compounds is linked with heart attack, stroke, and preeclampsia “The results suggest that vegetarian diet/fasting may have a beneficial influence on the concentration of serum peroxides and plasma fibrinogen concentration” (Høstmark et al., 1993).
Improved Gut Health
A short-term vegetarian diet may positively impact your gut health, by providing your gut with an abundance of “good” microbes that produce health promoting compounds, after as little as 4 days.
A study conducted by scientists from the Department of Nutrition at the University of California reported that switching from a fast food diet (high in saturated fats and refined carbohydrates) to a Mediterranean diet (rich in whole grains, fruits, vegetables, and nuts) had a positive impact on gut microbiome composition after just 4 days “Mediterranean diet altered human gut microbiome composition and its metabolites after just 4 days” (Zhu et al., 2020). Participants who followed a Mediterranean diet had more health promoting compounds in their gut “bacterially produced metabolites indole-3-lactic acid and indole-3-propionic acid, which have been shown to confer beneficial effects on neuronal cells, increased after the Mediterranean diet and decreased after the fast food diet”.
A study published in the journal, Gut, investigated the effect of an 8-week Mediterranean diet on gut health of participants who usually consumed a low intake of fruit and vegetables, and lead sedentary lifestyles. The results indicated that after the 8-week dietary intervention, participants had a positive improvement in gut health with an increase in diversity and gene richness “Switching subjects to a Mediterranean diet while maintaining their energy intake reduced their blood cholesterol and caused multiple changes in their microbiome and metabolome” (Meslier, 2020).
Reduced Chronic Medication
Short-term vegetarianism may lead to a reduction in chronic medication usage.
Scientists from the University of Rochester, who conducted an 8-week whole-food, plant-based lifestyle modification program on members of the community reported that over a quarter of participants were able to reduce or stop their chronic medication after the 8-week period “Twenty-one (26.9%) participants were able to decrease or stop at least one chronic medication” (Campbell et al., 2019).
A study published in the journal, Clinical Cardiology, reported a reduction in total medication usage after patients adhered to a 4-week raw plant-based diet “A defined plant-based diet can be used as an effective therapeutic approach in the clinical setting in the treatment of hypertension, hypercholesterolemia, and other cardiovascular risk factors while simultaneously reducing overall medication usage” (Najjar et al., 2018).
Improved Bowel Habits and Reduced Stress
Short-term vegetarianism can improve your bowel habits, and reduce stress.
A study published in the journal, Clinical Nutrition Research, evaluated the effectiveness of a 12-week vegetarian diet on stress status and bowel habits in middle school students and teachers. At the end of the 12-week period, the stress levels of the teachers had significantly reduced, and frequency of constipation decreased for both teachers and students “The results of this study confirmed that providing vegetables-focused meal in school improved nutrition status, bowel conditions in students and teachers and reduced the stress levels in teachers” (Lee et al., 2016).
Reduced Symptoms of Osteoarthritis
Short-term vegetarianism may reduce the symptoms of osteoarthritis. Osteoarthritis is one of the most common types of arthritis, and is characterised by degradation of cartilage and bone in joints.
A study conducted by scientists from the Department of Internal Medicine at Michigan University, investigated the effectiveness of a 6-week whole-food, plant-based diet (WFPB) on alleviating symptoms of osteoarthritis “WFPB diet was associated with a significant reduction in pain compared to an ordinary omnivorous diet, with statistically significant pain reduction seen as early as two weeks after initiation of the dietary modification” (Clinton et al., 2015).
6-week Raw Vegan Diet Rapidly Reverses Lupus Nephritis
A study published in the Journal of Disease Reversal and Prevention, investigated the effect of a 6-week raw, whole-food, plant-based diet on patients suffering from symptoms brought on by the autoimmune disease, lupus. After the 6-week diet, a positive improvement in kidney function, energy and joint pain levels was noted, with a 24-year old female no longer requiring a kidney transplant or dialysis “it was determined that she no longer needed dialysis or a kidney transplant. Her energy and joint pain levels also significantly improved” (Goldner, 2019).
Reduced Environmental Chemical Exposure (Antibiotics and Phthalates)
Adhering to a short-term vegetarian diet may lead to reduced levels of environmental chemical exposure to your body.
A study published in the journal, Environmental Research evaluated the influence of a short-term, 5-day vegetarian diet on the amount of environmental chemicals such as antibiotics and phthalates (chemicals used in plastic manufacturing) in the participants urine, they reported that following a vegetarian diet for 5 days lead to a decrease of antibiotics and phthalates in the body “even short-term changes in dietary behaviour may significantly decrease inadvertent exposure to antibiotics and phthalates and hence may reduce oxidative stress levels” (Ji et al., 2010).
Drawbacks of Short-Term Vegetarianism
In the previous sections we have looked at the many health benefits of a short-term vegetarian diet. In the section that follows we will discuss the potential drawbacks of short-term vegetarianism.
Although short-term vegetarianism (rich in whole grains, fruits and vegetables) is linked to positive health outcomes like improved cardiovascular health, improved gut health, weight loss, reduced blood pressure, improved bowel habits, and reduced stress levels; switching back to an omnivorous diet, rich in animal products and refined carbohydrates, could reverse the positive health effects obtained from a vegetarian diet.
Therefore, it is advised to work towards a sustainable long-term vegetarian diet in order to reap the short-term, and long-term health benefits a vegetarian diet can provide.
As studies have shown, short-term vegetarianism is capable of positively influencing your health in just a few days.
Following a plant-based diet, even for a short period of time has numerous benefits to your health including:
A well-planned, balanced and varied vegetarian diet rich in healthful plant-based foods such as whole grains, legumes, fruits, vegetables, nuts and seeds can provide your body with the nutrition it needs to maintain optimal physical and mental health.
If a short-term vegetarian diet can provide our bodies with such positive health changes in such a short period of time, imagine what a long-term vegetarian diet could do for your health and longevity.
Short-Term Vegetarian Studies
Benefits of Short-term Vegetarianism