The Flexitarian Diet

By Eva Batenhorst

Section 1: What is the Flexitarian Diet?

Section 2: Sample Diet Plan

Section 3: What Do the Studies Show?

Section 4: References


Section 1: What is the Flexitarian Diet?

Are you looking for the diet that best works around your life? One that has the main benefits of dieting but doesn’t feel restrictive? Then the flexitarian diet is the one for you! The majority of consumers for this diet are looking for a way to eat healthy without fully committing to a vegetarian or vegan diet. This diet allows you to have the best of both worlds because, unlike the almost every other diet, there is nothing that you have to completely eliminate from your life. When you are really craving that hamburger, this diet says “eat that burger! ( maybe only once a week)”. One of the most hailed aspects of of the diet is that is deemed much more of a lifestyle than a diet. Many people can sustain this way of living for their entire lives, with little to no extra effort or major shift in lifestyle (Turner-Mcgrievy, et al., 2015)  

Flexitarian comes from the combination of “flexible” and “vegetarian”, their diet is similar to a vegetarian with more flexible rules.  They mostly stick with a diet of primarily vegetables, fruits, nuts/seeds, grains, but unlike vegetarians they do not avoid meat and fish entirely (Raphaely, et al., 2013). The flexitarian diet allows for the occasional consumption of meat and fish, making it more desirable and easier to follow because someone can go out and enjoy a dinner with friends and not have to worry about having to order something without meat.  “Most consumers can be grouped into meat consumers, meat avoiders, or meat reducers” (J. Emma, 2016); flexitarians can be grouped in meat reducer category.

The flexitarian diet is a plan that encourages high consumption of plant based food with moderate to low consumption of of meat or other animal products. It is deemed more flexible than the popular vegetarian or vegan diets, and like most vegan or vegetarians trends, flexitarianism develops into a lifestyle and tends to be a very sustainable diet plan. They mostly stick with a diet of primarily vegetables, fruits, nuts/seeds, grains, but unlike vegetarians they do not avoid meat and fish entirely. The flexitarian diet allows for the occasional consumption of meat and fish, making it more desirable and easier to follow because someone can go out and enjoy a dinner with friends and not have to worry about having to order something without meat.  This diet plan is less cut and dry than most popularized plans that have specific, recommended amount of calorie or macronutrient consumption. Basically to sustain this diets limit carbohydrate and sugar intake, eliminate processed food, consume high amounts of plant based food, and limit meat intake. It is recommended that the amount of meat reduction increases over time. For example, assume an individual consumes 21 meals/week, a beginner flexitarian should have 6-8 meals/week without meat. An intermediate flexitarian would have 9-14 meatless meals and the advanced flexitarian would have 15 or more meatless meals.

The majority of consumers for this diet are looking for a way to eat healthy without fully committing to a vegetarian or vegan diet. This diet allows you to have the best of both worlds because, unlike the almost every other diet, there is nothing that you have to completely eliminate from your life. When you are really craving that hamburger, this diet says “eat that burger! ( maybe only once a week)”.

Even though this is no hassle diet, it reems major benefits. It has been shown that a flexitarian diets can reduce:

  • Total body weight
  • Body Mass Index
  • Waist circumference
  • Body fat percentage
  • Cholesterol
  • Blood pressure
  • Blood glucose levels
  • Risk of coronary heart disease, diabetes, and cancer

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Section 2: Sample Diet Plan

A Day in the Life of a Flexitarian

(Total Calories: 1,155 – Total caloric intake can be individually modified for lifestyle and activity level)

Breakfast:

1 egg, cooked in water or low fat oil (coconut oil)

Avocado toast with whole grain bread

Cooked peppers and spinach

Caloric Intake: 426

 

Lunch:

Quinoa Salad with grilled chicken, bell peppers, tomatoes, avocado, onion, black beans, and corn.

Caloric Intake: 357

 

Dinner:

Tacos with grilled fish, corn tortillas, side salad

Caloric Intake: 319

 

Snack:

Grapes and almonds

Caloric Intake: 53

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Section 3: What Do the Studies Show?

Over all, the research shows that flexitarians show they same benefits of those that follow a vegan or vegetarian diet but to less of an extreme, most due to the additional consumption of meat or fish. One of the most common reasons to diet is to lose weight or body fat. In an analysis of multiple diets (vegan, flexitarian, pescotarian, vegetarian, and omnivorous), flexitarians should an average of 3.7% decrease in body in comparisons to meat eaters. This decrease was calculated after the first 6 months of the diet. A study in Korea involving post-menopausal women who sustained flexitarian diets for about 20 years showed the long term effects of this diet and the participants displayed a significantly lower body weight, body mass index (BMI), and percentage of body fat compared with non-vegetarians (Kim, et al., 2015). 71,751 participants took part in the Adventist Health Study 2 from 2002-2007 showed that Body Mass Index (BMI) was highest in non-vegetarians (mean 28.7 kg/m2), slightly lower in flexitarians (mean 27.4 kg/m2), and lowest in strict vegetarians (mean 24.0 kg/m2) (Rizzo, et al., 2011). These findings are similar to earlier trends (2002–2006 analysis) showing that mean BMI was lowest in vegans (23.6 kg/m2) and incrementally higher in flexitarians (27.3 kg/m2), and non-vegetarians (28.8 kg/m2) (Tonstad, et al., 2011). Another study looked at the difference in waist circumference and BMI in flexitarians vs meat eaters and found that both were lower in flexitarians (about 21.7in and 10.9%) compared to meat eaters (about 27.7in and 15.4%) (Chiu, et al., 2015).

The flexitarian diet has also resulted in lower cholesterol in individuals. In a six month study comparing various diets, reduced meat eaters had a had a significant decrease in cholesterol intake than non-adherent PV/SV (P = 0.02) or omnivore participants (P = 0.04) (Moore, et al., 2015). In a separate study, authors observed that postmenopausal women following an flexitarian diet for more than 20 years had significantly lower glucose (p < 0.001), insulin levels, and homeostatic model assessment of insulin resistance compared with NV controls (Kim, et al., 2015). A meta-analysis involving forty-one randomised controlled trials found a diet with increased grains and leafy vegetables was associated with a significant reduction in mean serum total cholesterol, LDL-C and TAG and a significant increase in HDL cholesterol. LDL reduction was about 10-15% across the analysis of all the forty one studies (McEvoy, et al., 2012). Though in significant increase in HDL cholesterol sounds alarming, this is actually deemed the “good cholesterol” and this increase is correlated with a healthier life.

Another major benefit from this diet was an observed lower blood pressure. Evidence from the DASH study suggests that a low meat intake diet has a significant lowering effect on blood pressure. This result was seen in participants across the board regardless of body weight and sodium intake. They also saw the same results in both hypertensive and normotensive adults (McEvoy, et al., 2012). Cross-sectional data from the Adventist Health Study-2 (n = 773) showed that the prevalence of metabolic syndrome was highest in NVs (39.7%), intermediate in SVs (37.6%), and lowest in vegetarians (25.2%). (Rizzo, et al., 2011). Metabolic syndrome is a cluster of conditions such as increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels. Together these symptoms increasing your risk of heart disease, stroke and diabetes (Mayo Clinic). Research involving 26 postmenopausal women from convents found that omnivores had significantly higher systolic and diastolic pressures than the SVs (Rodenas, et al., 2011).

Disease prevention is often tied to diets. The overused expression “You are what you eat” is actually expressed and validated in the conversation of diet and disease prevention. However, diet is only a small contributor to prevention and can vary in many different cases. There is limited information on whether this diet plan can have positive effects in preventing cancer. The data is largely inconsistent and seems to vary greatly by the cancer site. A study has concluded that a decrease in meat consumption could result in a possible reduction in colon and bladder cancer risks (Fraser et al., 1999). Another study looked at breast cancer and the respective correlations to diet. This study found a positive correlation in increased meat intake and increased cancer risks. UK Women’s Cohort Study suggested that women who did not eat any meat had a significantly lower risk for breast cancer than did women who were regular meat-eaters. In that study a response based in intake amount was demonstrated, with each increase of 50 g/d in red meat intake increasing breast cancer risk by 11 % (McEvoy, et al., 2012). Coronary Heart Disease (CHD) has been studied in great depth when it comes to meat reducing diets. A pooled analysis of five prospective cohort studies, involving approximately 76 000 subjects from the USA, the UK and Germany, over a mean follow-up period of 6-10 years, reported that vegetarians had a 24 % reduction in mortality from CHD compared with regular meat-eaters. Further investigation of the vegetarian groups, within that analysis, found that the greatest reductions in CHD mortality (34 %) were observed in individuals eating fish but no meat and in lacto-ovo-vegetarians when compared with regular meat-eaters. Furthermore, occasional meat-eaters demonstrated a 20 % reduction in CHD when compared with regular meat-eaters. (Key, et al., 1999) In this same analysis, no significant differences were observed for stroke mortality or overall mortality between vegetarians and non-vegetarians (Key, et al.,1999). Those who are affected by diabetes or prone to diabetes may seek some benefit in participating in the flexitarian diet. In 2005-2006, India constricted a national health survey and found that subjects adhering to a flexitarian diets were associated with reduced likelihood of diabetes. A total of 156,317 people participated with ages 20-49 (Agrawal, et al., 2014). Another study constructed by Adventist Health found cases of diabetes developed were lowest in vegans (0.54%) and followed by flexitarians (0.92%) compared with 2.1% in Non-Vegetarians (Tonstad, et al., 2011).

A side note about the flexitarian diet is that many researchers have noticed a correlation with negative cognitive effects and the flexitarian lifestyle. The research doesn’t imply that following a flexitarian lifestyle is correlated with these negative effects but the reasons for people to follow the lifestyle may. Restrained eating, intention to restrict food intake deliberately in order to prevent weight gain or to promote weight loss (Tuschl, 1990), is a major contributing factor that can lead towards eating disorders. Flexitarians were significantly more restrained than the other diet groups. This finding is consistent with other research that found that semi-vegetarians were significantly more restrained than lacto-ovo- vegetarians and vegans (Forestall, et al., 2018). Restrained eating occurs when there is a lack of regulation and maintenance of food intake. This often manifests in episodes of starvation and binge eating. Restrained eating is positively correlated with depression (Heaven, et al., 2001). Although restrained eating differs from disordered eating, it is often used as a marker for disordered eating and is believed to be a risk factor for the development of an eating disorder (Polivy, et al., 2002).

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Section 4: References

Agrawal S, Millett CJ, Dhillon PK, Subramanian SV, Ebrahim S. Type of vegetarian diet, obesity and diabetes in adult Indian population. Nutr J (2014) 13:89. doi:10.1186/1475-2891-13-89

Baines S, Powers J, Brown WJ. How does the health and well-being of young Australian vegetarian and semi-vegetarian women compare with non-vegetarians? Public Health Nutr (2007) 10(5):436–42. doi:10.1017/ S1368980007217938

Fraser GE (1999) Associations between diet and cancer,ischemic heart disease, and all cause mortality in non-Hispanic white California Seventh-day Adventists. Am J Clin Nutr 70, Suppl. 3, 532S–538S.

Heaven PC, Mulligan K, Merrilees R, Woods T, Fairooz Y. Neuroticism and conscientiousness as predictors of emotional, external, and restrained eating behaviors. Int J Eat Disord. (2001) 30:161–6. doi: 10.1002/eat.1068

Key TJ, Fraser GE, Thorogood M et al. (1999) Mortality in vegetarians and non-vegetarians: detailed findings from a collaborative analysis of 5 prospective studies. Am J Clin Nutr 70, Suppl. 3, 516S–524S.

Kim MH, Bae YJ. Comparative study of serum leptin and insulin resistance levels between Korean postmenopausal vegetarian and non-vegetarian women. Clin Nutr Res (2015) 4(3):175–81. doi:10.7762/cnr.2015.4.3.175

J., Emma. “Flexitarian Diets and Health: A Review of the Evidence-Based Literature.” Frontiers, Frontiers, 7 Dec. 2016, www.frontiersin.org/articles/10.3389/fnut.2016.00055/full.

Mcevoy, Claire T, et al. “Vegetarian Diets, Low-Meat Diets and Health: a Review.” Public Health Nutrition, vol. 15, no. 12, 2012, pp. 2287–2294., doi:10.1017/s1368980012000936.

Moore WJ, McGrievy ME, Turner-McGrievy GM. Dietary adherence and acceptability of five different diets, including vegan and vegetarian diets, for weight loss: the new DIETs study. Eat Behav (2015) 19:33–8. doi:10.1016/ j.eatbeh.2015.06.011

Polivy J, Herman CP. Causes of eating disorders. Annu Rev Psychol. (2002) 53:187–213. doi: 10.1146/annurev.psych.53.100901.135103

Raphaely, Talia, et al. “Flexitarianism (Flexible or Part-Time Vegetarianism): A User-Based Dietary Choice for Improved Wellbeing.” IGI Global, IGI Global, 1 July 2013, www.igi-global.com/article/flexitarianism-flexible-or-part-time-vegetarianism/101343.

Rizzo NS, Sabate J, Jaceldo-Siegl K, Fraser GE. Vegetarian dietary patterns are associated with a lower risk of metabolic syndrome: the adventist health study 2. Diabetes Care (2011) 34(5):1225–7. doi:10.2337/dc10-1221

Rodenas S, Sanchez-Muniz FJ, Bastida S, Sevillano MI, Larrea Marin T, Gonzalez-Munoz MJ. Blood pressure of omnivorous and semi-vegetarian postmenopausal women and their relationship with dietary and hair concentrations of essential and toxic metals. Nutr Hosp (2011) 26(4):874–83.doi:10.1590/S0212-16112011000400030

Tonstad S, Stewart K, Oda K, Batech M, Herring RP, Fraser GE. Vegetarian diets and incidence of diabetes in the adventist health study-2. Nutr Metab Cardiovasc Dis (2013) 23(4):292–9. doi:10.1016/j.numecd.2011.07.004

Turner-Mcgrievy, Gabrielle M., et al. “Comparative Effectiveness of Plant-Based Diets for Weight Loss: A Randomized Controlled Trial of Five Different Diets.” Nutrition, vol. 31, no. 2, 2015, pp. 350–358., doi:10.1016/j.nut.2014.09.002.

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