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Food – Vice or Virtue?
A nutritional comparison of leading diets
Hannah Rohrlach
Mediterranean and Okinawan diets have been hailed the best of the best, and interestingly share a key nutritional feature with the increasingly popular vegetarian and vegan diets.
According to the World Health Organization (WHO), optimal diets have one thing in common: They are wholefood and plant based. ©Shutterstock/Ollyy

Although these diets may look different from the outside, similarities are revealed in the nutrition science behind them. The six essential nutrients1 can be found in many different foodstuffs, therefore the ideal diet can be an endless number of dietary combinations. According to the World Health Organization (WHO)2, optimal diets all share a common, important feature in that they largely comprise fruit, vegetables, wholegrain cereals, pulses, nuts and seeds. In short, they are wholefood and plant based3. Plant foodstuffs are rich in vitamins, minerals, fibre and phytonutrients, which not only support a functioning metabolism but prevent and fight lifestyle diseases such as cardiovascular diseases4, type 2 diabetes5 and some cancers6, that are major causes of death globally7.


The Mediterranean diet


While there is no single ‘Mediterranean diet’, countries such as Spain, Greece, Italy, France, Turkey and Lebanon have traditionally eaten an abundance of plant foodstuffs, moderate amounts of fish, eggs and dairy products, and small quantities of red meat. The generous intake of olive oil and regular but small amounts of red wine make this diet unique. Olive oil replaces saturated fats8 with monounsaturated fats while additionally providing beneficial anti-inflammatory compounds9. Red wine adds polyphenols, strong antioxidants acting alongside other phytonutrients from fruit, vegetables and pulses, which protect cardiovascular health10.




The population of the Japanese island of Okinawa is famous for having one of the longest life expectancies in the world. As the old Okinawan saying goes, “At 70, you are still a child; at 80, you are just a youth; and at 90, if the ancestors invite you into heaven, ask them to wait until you are 100 and then you might consider it.” The traditional diet of this Blue Zone11 consists of over 95% whole-plant foodstuffs, primarily native purple sweet potatoes plus small to moderate amounts of rice, cereals, pulses, other fruit and vegetables, fresh herbs and spices, fish, tofu, fermented soya foodstuffs, and occasionally pork. Of interest is the practice of ‘hara hachi bu’, a habit of only eating to 80% fullness. This restricted intake, along with a proper ratio of fats and phytonutrients, are the suggested reasons for the low occurrences of inflammation and chronic disease in this population and for its increased sense of wellbeing12.




Instead of being determined by geography, vegetarian diets may be chosen for ethical or environmental reasons, religious beliefs, taste or affordability. Large communities follow this dietary pattern, such as Hindus, Buddhists, and Jainists. While excluding red meat, poultry and often fish, most will still consume dairy products and eggs. Lack of protein is often unnecessarily feared as it can be readily sourced from dairy products, eggs, pulses, nuts, tofu and soya foodstuffs. Iron is a little trickier to come by but requirements can be met by consuming wholegrains, prunes, dried fruit, pulses, nuts, seeds and leafy green vegetables. Not surprisingly, with a high intake of low-kilocalorie but nutrient-dense plant foodstuffs and a balanced fat supply, the vegetarian diet has been associated with health benefits ranging from preventing and managing type 2 diabetes13 to decreasing the risk of certain cancers14. The Seventh-Day Adventist community in Loma Linda, California (another Blue Zone) is the most well-known studied example.




Compassionately and ethically motivated, vegans exclude all animal foodstuffs and by-products including dairy products, honey and gelatin. Despite obtaining all the plant-related health benefits described above, there is little evidence of the health benefits of a vegan diet. Some nutrient needs may be hard to fulfil, meaning a vegan diet must be varied, well planned and supplemented if it is to meet nutritional guidelines. Iron, protein and zinc are present in a variety of plant foodstuffs, while calcium can be found in, tofu, almonds, pulses, leafy green vegetables, different kinds of fortified juices and non-dairy milk, as well as in breakfast cereal. Vitamin B12 can only be obtained from supplements or fortified foodstuffs.


Beyond nutrients


It is also important to remember that taking pleasure in cooking and eating at home, enjoying sharing a meal with others, and not overeating are also vital parts of a healthy diet. While there is no such thing as one best diet to suit everybody, the healthiest patterns will always be nutritionally balanced and plant based. It is easy then to see why fad diets, which cut out one or more nutrient groups, cannot actually maintain their health claims for very long. Fortunately, the principles of a healthy diet are universal and adaptable to different cultures, individual preferences and the availability of local foodstuffs.

The six essential nutrients are proteins, carbohydrates, fats (lipids), vitamins, minerals and water.

The term ‘plant-based’ is often mistaken for vegetarian or vegan, but it literally means the diet is based on plants, but can still include small to moderate amounts of animal products.

WANG X et al., 2014. Fruit and vegetable consumption and mortality from all causes, cardiovascular disease, and cancer: systematic review and dose-response meta-analysis of prospective cohort studies. BMJ, vol. 349

ESTRUCH R et al., 2013. Primary Prevention of Cardiovascular Disease with a Mediterranean diet. New England Journal of Medicine, vol. 368, pp.1279-1290.

KAHLEOVA H et al., 2011. Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes. Diabetic Medicine, vol. 28, iss. 5, pp.549-559.

TRAPP, CB & BARNARD, N, 2010. Usefulness of Vegetarian and Vegan Diets for Treating Type 2 Diabetes. Current Diabetes Reports, vol. 10, iss. 2, pp.152-158.

TONSTAD S. et al. 2009. Type of vegetarian diet, body weight, and prevalence of type 2 diabetes. Diabetes Care, vol. 32, iss. 5, pp.791-796.

Different dietary choices have been found to have damaging or protective effects on cancers of the pancreas, bowel, colon, mouth, pharynx, larynx, oesophagus, lungs and breast.

Cardiovascular disease (CVD) is the leading cause of death globally, an estimated 17.5 million people died from CVD in 2012.

HOOPER L et al, 2015. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database of Systematic Reviews, vol. 10, iss. 6.

PARKINSON, L & CICERALE S, 2016. The Health Benefiting of Virgin Olive Oil Phenolic Compounds. Molecules, vol. 21, iss. 12, p.1734

APARICIO-SOTO, M, et al. 2016. Extra virgin olive oil: a key functional food for prevention of immune-inflammatory diseases. Food & Function, vol. 7, iss. 11, pp.4492-4505.

VIDAVALUR R et al., 2009. Significance of wine and resveratrol in cardiovascular disease: French paradox revisited. Experimental & Clinical Cardiology, vol. 11, iss. 3, pp.217-225.

BROWN L, et al., 2009. The Biological Responses to Resveratrol and Other Polyphenols from Alcoholic Beverages. Alcoholism: Clinical and Experimental Research, vol. 33, iss. 9, pp.1513-1523.

Blue Zones are regions with exceptionally high rates of longevity. Lead researcher Dan Buettner has discovered and reported on 5 Blue Zones: Sardinia in Italy, Loma Linda in California, Nicoya in Costa Rica, Ikaria in Greece and Okinawa in Japan. Sadly this trend is changing, as younger generations, who no longer follow the traditional diet or lifestyle, do not have the same health outcomes as their elders.

WILLCOX, DC et al., 2009. The Okinawan Diet: Health Implications of a Low-Calorie, Nutrient-Dense, Antioxidant-Rich Dietary Pattern Low in Glycemic Load. Journal of the American College of Nutrition, vol. 28, sup. 4, 500S-516S.

WILLCOX, BJ et al, 2007. Caloric Restriction, the Traditional Okinawan Diet, and Healthy Aging. Annals of the New York Academy of Sciences, vol. 1114, iss. 1, pp.434-455.

WILLCOX DC et al., 2014. Healthy aging diets other than the Mediterranean: A focus on the Okinawan diet.. Mechanisms of Ageing and Development See note 5 [Links visited on 03.04.2017]

THOMPSON, Janice L, MANORE, Melinda, VAUGHAN, Linda, 2011. The Science of Nutrition 2nd ed. San Francisco: Benjamin Cummings.

BUETTNER, Dan, 2008. The Blue Zones: lessons for living longer from the people who’ve lived the longest. Washington DC: National Geographic Society.

THOMAS, Briony, BISHOP, Jacki, 2007. Manual of Dietetic Practice 4th ed. Oxford: Blackwell Publishing.

The Vegan Society

[Links visited on 03.04.2017]

Hannah Rohrlach
Accredited Practising Dietitian
Adelaide, Australia

Hannah is an Australian Dietitian working in creative and innovative food education. Having qualifications in both nutrition and visual arts, she is passionate about bringing the two worlds together. One of her recent achievements was co-founding an award-winning season of unique food events titled Post Dining at the 2016 Adelaide Fringe Festival. Hannah is particularly interested in sustainable food, interactive nutrition education, native ingredients and edible insects.

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