Plant-based Nutrition Reduces Fatigue, Depression and Anxiety

vegan diet and depression and fatigue

Photo by Michael Cannon

By Case Adams, Naturopath

Researchers from the Physicians Committee for Responsible Medicine in Washington D.C. have found that switching to a diet with more plant-based foods significantly reduces depression, anxiety and fatigue.

In this multi-center study, the researchers tested 292 men and women who had a body mass index equal to or more than 25 kg/m2 – a marker for being overweight – or had a previous diagnosis of having type 2 diabetes. A total of 211 people completed the study and completed all the final analyses and examinations.

The research was conducted at ten different corporate sites of GEICO, a major health insurance provider and insurer of U.S. government employees. The subjects were employees of GEICO – which stands for Government Employee Insurance Co.

The researchers tested the patients for fatigue, depression, emotional well-being, anxiety and other parameters utilizing the Short Form-36 questionnaire (SF-36). This is a report of the general well-being and health status of the person, based on the Medical Outcome Study – called the RAND-36.

The questionnaire contains eight sections, which score the patients’ level of vitality, physical condition, pain levels, perceptions of health, physical and emotional role functions, their social role function and mental health and well-being.

This is a standardized test that has been in use for nearly two decades.

The researchers utilized before and after scores, following the diet intervention that lasted 18 weeks – about four and a half months.

Half of the group went to a plant-based diet, while the other half made no diet changes – continuing whatever current diet they had Weekly consultations and cafeteria options were available to the test subjects.

The plant-based diet group was asked to focus their diet upon whole grains such as oats and whole wheat breads, vegetables in all forms, nuts and cooked legumes and fruits. They did not restrict the diet with regard to calories or fullness.

Both groups were advised not to alter any other part of their lifestyle, including more or less exercise.

The researchers also utilized 24-hour diet recalls to study the nutrient intake of the subjects.

The researchers used T-testing and Chi-square (X2) testing to control variables and quantify the results.

At the end of the period, the patients scores in the following areas were significantly higher than at the beginning of the study:

  • depression
  • anxiety
  • fatigue
  • emotional well-being
  • daily functioning because of physical health
  • general health
  • impairment because of health
  • overall work impairment because of health
  • non-work-related activity impairment because of health

Each of these parameters had higher scores with confidence levels ranging from 98% to 99%.

For example, after the 18 weeks, those who ate more plant-based foods scored an average of 62.9 on the fatigue measure of the SF-36, while the control diet group scored an average of 45.9. For depression the averages were 81.8 versus 74.6 respectively. And for anxiety, the average scores were 72.6 versus 64.9. Fatigue had the highest score difference in scores at 17.1 (62.94 minus 45.88), followed by physical role limitations at 14.4, general health at 12.9 and social functioning at 10.1 (score difference between the two groups).

The researchers concluded that the “dietary intervention improves depression, anxiety, and productivity” in their paper.

Plant-based diet also reduced weight, cholesterol and diabetes risk

The research also found that the plant-based diet resulted in several other health parameters, including significant weight loss and better cholesterol and HbA1C levels.

This part of the study, published in 2013, found that LDL-cholesterol – the “bad” lipoprotein form – fell by 13 mg/dl in the plant-based group but only 1.7 mg/dl in the control group – a difference of more than 700% or seven times. Meanwhile, HbA1C levels – a marker for diabetes risk – fell by 0.7% in the plant-based group, while only falling 0.1% in the control diet group.

The plant-based diet group also lost an average of 2.9 kilograms during the 18 weeks – equivalent to over six pounds. The control group had practically no weight loss – less than 1/6 of one pound on average. Many of the subjects gained weight on the control diet.

Two of the subjects lost more than 40 pounds during the four and a half months. The average BMI drop was a little over 1 kg/m2 for the plant-based group and close to nil for the control group.

The plant-based diet group also had a reduction in blood pressure. One of the study’s authors, Susan Levin, M.S., R.D. stated:

“GEICO’s workplace nutrition program helped employees lose weight and reduce blood pressure and cholesterol levels.”

The plant-based diet plan also reduced sick days for the workers and increased productivity at work. The researchers stated:

“Employers may be motivated to provide obesity-related interventions, because they often assume financial liability for health outcomes and costs. Epidemiologic studies have shown that populations consuming low-fat, plant-based diets reduce body weight, improve plasma lipid concentrations, reverse coronary atherosclerosis, and improve type 2 diabetes management.”


This and other studies have shown that plant-based foods are alkaline in nature, and thus reduce the formation and damage of free radicals, which can produce a variety of mental and physical disorders as we age.

Plant-based foods neutralize these free radicals because plants produce antioxidants in order to protect themselves from the onslaught of environmental toxins. These antioxidants transfer to us through these foods.

Learn about the scientifically proven healthiest diet: The Ancestor’s Diet.


Agarwal U, Mishra S, Xu J, Levin S, Gonzales J, Barnard ND. A Multicenter Randomized Controlled Trial of a Nutrition Intervention Program in a Multiethnic Adult Population in the Corporate Setting Reduces Depression and Anxiety and Improves Quality of Life: The GEICO study. Am J Health Promot. 2014 Feb 13.

Mishra S, Xu J, Agarwal U, Gonzales J, Levin S, Barnard ND. A multicenter randomized controlled trial of a plant-based nutrition program to reduce body weight and cardiovascular risk in the corporate setting: the GEICO study. Eur J Clin Nutr. 2013 Jul;67(7):718-24. doi: 10.1038/ejcn.2013.92.

Physicians Committee for Responsible Medicine.

Case Adams is a California Naturopath with a PhD in Natural Health Sciences, and Board Certified Alternative Medicine Practitioner. He has authored 26 books on natural healing strategies. “My journey into writing about alternative medicine began about 9:30 one evening after I finished with a patient at the clinic I practiced at over a decade ago. I had just spent the last two hours explaining how diet, sleep and other lifestyle choices create health problems and how changes in these, along with certain herbal medicines and other natural strategies can radically yet safely turn ones health around. As I drove home that night, I realized I needed to get this knowledge out to more people. So I began writing about health with a mission to reach those who desperately need this information. The strategies in my books and articles are backed by scientific evidence along with wisdom handed down through traditional medicines for thousands of years.” Case connects with the elements by surfing, hiking and being a beach bum.

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