Why a diet consisting mainly of fruit is bad for you

Aug 25, 2021

4 min

Plant-based diets have become increasingly popular in recent years, both for health and ethical reasons. One extreme form of plant-based diet is “fruitarianism”, a diet based largely on consumption of raw fruit. At first glance, this may sound healthy, but what effect will this type of restrictive diet have on the body? And is it a healthy diet choice?



There is solid evidence that plant-based diets are good for the body. Plant-based diets may reduce the risk of heart disease by 40% and stroke by 29%. Plant-based diets have also been shown to be a useful strategy for helping people lose weight.


While plant-based diets have clear benefits for health and environmental sustainability, fruitarianism is one of the most restrictive diet choices available and has almost no evidence to support health benefits. There is no definitive description of what a fruitarian diet should consist of, although one commonly cited “rule” is that between 55% and 75% of the diet should comprise raw fruit. Beyond this, there is some variability; some fruitarians eat grains, some also eat nuts and oils.


Apple co-founder, Steve Jobs, experimented with a fruitarian diet, supplementing it with nuts, seeds and grains. Some adherents of fruitarianism stick to an 80-10-10 rule: 80% of calories coming from fresh fruit and vegetables, 10% coming from protein and 10% from fat. This rule is mistakenly based on the belief that humans are not omnivores, but “frugivores” – animals that prefer to eat raw fruit. Proponents of this belief state that the human digestive system is physiologically designed to digest fruit and raw vegetables. While this may have once been true, the human body has evolved.



Some fruitarians claim that “going raw” has had marked benefits including curing cancer and eliminating bloating and body odour. There is no robust evidence to back up these claims.


The idea of consuming a fruit-only (or fruit-heavy) diet might appear a healthy option at first glance, but there are potentially many problems with this form of restrictive eating.


There are clear and significant physical health issues to consider when the human body is provided with a largely fruit-based diet. Following this eating pattern excludes essential food groups and nutrients that the body needs to maintain normal health.


While most fruit is considered to be healthy and nutritious, a diet that almost solely relies on fruits will be deficient in nutrients, including protein, iron, calcium, vitamin B (including vitamin B12) and D, zinc and omega-3 fatty acids. Deficiency in these nutrients can have significant health implications including rickets and osteomalacia (a softening of the bones), anaemia and issues with bones, muscles and skin. Put simply, fruit does not contain all the nutrients the body needs.


In addition to what is missing in a fruitarian diet, the high levels of fructose have to be considered. Fructose is a simple sugar, like glucose, but the human body processes it very differently. Fructose is metabolised solely in the liver. Excess fructose consumption can cause fat buildup in the liver, leading to insulin resistance in the liver and non-alcoholic fatty liver disease. While there is controversy as to whether fructose from fruit is as bad as fructose syrup, which is added to foods to sweeten them, experiments in rats fed a high fructose diet showed similarities to human fatty liver disease.


Serious harm

Beyond the potential physical effects of fruitarianism, restrictive diets are also often associated with an eating disorder known as orthorexia nervosa, or an unhealthy obsession with eating “pure” food only. This means that what can start off as a healthy move towards eating more fruit and vegetables and less junk food can lead to an eating disorder, depression and anxiety.


Worryingly, isolated cases of death or significant disease have been reported when a fruitarian style diet has been followed. Examples include a nine-month-old girl dying after being fed a fruit-only diet. The girl died vastly underweight and malnourished. Additionally, a 49-year-old man was recently reported to have developed reversible dementia after subsisting on a fruit-only diet.


With little evidence of the benefits of such a restrictive diet, it is clear that people who follow this restrictive diet are potentially putting their health at serious risk. Supplementation with foods that provide the missing nutrients may help, but may be rejected by some with orthodox views on fruitarianism. Before changing a diet, especially if the change is going to be extreme, it is always wise to speak to your doctor first. Incorporating more fruit and vegetables as part of a balanced diet is a far safer, healthier way to approach fruit consumption.

You might also like...

Check out some other posts from Aston University

3 min

Professor Sangeeta Khorana made a Fellow of the Academy of Social Sciences

Professor Sangeeta Khorana, professor of international trade policy at Aston University, has been made a Fellow of the Academy of Social Sciences Fellows are elected for their contributions to social science, including in economic development, human rights and welfare reform The 2025 cohort of 63 Fellows will join a 1,700-strong Fellowship with members from academia, the public, private and third sectors. Professor Sangeeta Khorana, professor of international trade policy at Aston University, has been made a Fellow of the Academy of Social Sciences as part of the Autumn 2025 cohort. The 63 new Fellows have been elected from 39 UK organisations, comprising 29 higher education institutions, as well as think tanks, non-profits, business, and from countries beyond the UK including Australia and China. The Academy of Social Science’s Fellowship comprises 1,700 leading social scientists from academia, the public, private and third sectors. Selection is through an independent peer review which recognises their excellence and impact. Professor Khorana has more than 25 years of academic, government and management consulting experience in international trade. She has worked for the Indian government as a civil servant and on secondment to the UK Department for Business and Trade. Her expertise includes free trade agreement (FTA) negotiations and World Trade Organization (WTO) issues. As well as sitting on various expert committees, Professor Khorana is an advisor on gender and trade to the Commonwealth Businesswomen’s Network in London and serves on Foreign Investment Committee of the PHD Chambers of Commerce and Industry, India. The Autumn 2025 cohort of Fellows have expertise in a range of areas including educational inequalities, place-based economic development, human rights protection, the regulation of new technologies, and welfare reform, highlighting the importance, breadth and relevance of the social sciences to tackling the varied challenges facing society today. As well as excellence in research and professional applications of social science, the new Fellows have also made significant contributions beyond the academy, including to industry, policy and higher education. Professor Khorana said: “I am deeply honoured to be elected a Fellow of the Academy of Social Sciences. This recognition underscores not only the importance of international trade policy as a driver of inclusive and sustainable growth, but also the role of social sciences in shaping fairer and more resilient societies. At Aston University, my research seeks to bridge academia, government and industry to inform evidence-based trade policy for global cooperation. I am proud to contribute to the Academy’s mission of demonstrating how social science knowledge and practice can address some of the most pressing challenges of our time.” President of the Academy, Will Hutton FAcSS, said: “It’s a pleasure to welcome these 63 leading social scientists to the Academy’s Fellowship. Their research and practical applications have made substantial contributions to social science and wider society in a range of areas from international trade policy and inclusive planning systems through to innovative entrepreneurship and governing digital technologies. We look forward to working with them to promote further the vital role the social sciences play in all areas of our lives.”

4 min

Play, Learn, Lead: How Aston’s Gamification-Driven MBA Is Redefining Business Learning

Professor Helen Higson OBE of Aston Business School, discusses why gamification is embedded in all of the School's postgraduate portfolio of degrees Give the students something to do, not something to learn; and the doing is of such a nature as to demand thinking; learning naturally results. (attributed to John Dewey, US educational psychologist (1859-1952) Imagine you’re the CEO of a cutting-edge robotics firm in 2031, making high-stakes decisions on R&D, marketing and finance; one misstep and your virtual company could collapse. You win, lose, adapt, and grow. This isn’t a case study, it’s your classroom experience at Aston Business School in Birmingham. Imagine you’re participating in Europe’s biggest MBA tournament, the University Business Challenge, where your strategic flair and financial acumen will be tested against the continent’s sharpest minds. Then you’re solving real-world sustainability crises in the Accounting for Sustainability Case Competition, crafting solutions that could be showcased in Canada. What if you could do all this from your classroom seat, armed with only your MBA learnings, teamwork and the thrill of gamified learning. At Aston, we believe the best way to master business is by doing business. That’s why we’ve embedded active learning through games, simulations, and competitions across all our postgraduate programs. The results? Higher engagement, deeper learning, and students who graduate with confidence and real-world skills. Research says gamified learning boosts motivation, lowers stress, and helps students adopt new habits for lifelong success. As educational researchers Kirillov et al. (2016) found, “Gamification creates the right conditions for student motivation, reduces stress, and promotes the adoption of learning material—shaping new habits and behaviours.” This has led to what Wiggins (2016), calls the “repackaging of traditional instructional strategies”. In Aston Business Sschool we have long embraced this approach as a way of increasing student outcomes and stimulating more student engagement in their learning. Our Centre for Gamification in Education (A-GamE), launched in 2018, is dedicated to advancing innovative teaching methods. We run regular seminars with internal and external speakers showcasing gamification adoption, design and research and we use these techniques across the ABS in a wide range of disciplines. (We have included two examples of this work in our list of references.) Furthermore, in 2021 we published a book which outlines the diverse ways in which we use these methods (Elliott et al. 2021). Subsequently, during 2024 we redesigned all our postgraduate portfolio of degrees, and as part of this initiative games and simulations were embedded across all programmes. Why Gamification Works Through simulations like BISSIM, students step into executive roles, steering futuristic companies through the twists and turns of a dynamic marketplace. A flagship programme running since 1981, BISSIM was developed in collaboration between academics from ABS and Warwick Business School, and every decision on R&D, marketing, or HR has real consequences as teams battle each other for the top spot. After each year of trading the results are input into the computer model. The results are then generated for each company in the form of financial reports, KPIs and other non-financial results and messages. Each team’s results are affected by their own decisions and the competitive actions of the other teams, as well as the market that they all influence. This year one of our academics, Matt Davies, has been awarded an Innovation Fellowship further to commercialise the game. Competitions with Global Impact We also encourage students to take part in national and international competitions which have the same effect of developing their engagement with real-life business problems on a global scale. Beyond the classroom, Aston students represent the university in major competitions like the University Business Challenge (in which ABS had the highest number of UK teams this year) and the Accounting for Sustainability (A4S) Case Competition, for which we are an “anchor business school”. Here, theory gets stress-tested against real-world scenarios and top talent from around the globe. The result? Award-winning teams, global experience, and friendships built under pressure. At the heart of this approach is Aston’s Centre for Gamification (A-GamE), dedicated to making learning interactive, motivating, and fun. Regular seminars, fresh research, and close ties to industry keep the curriculum evolving and relevant, so students graduate ready to lead, adapt, and thrive in any business environment. Why does it matter? In a volatile, fast-paced economy, employers appreciate agility, teamwork and decisiveness. At Aston, every simulation and competition is geared towards sharpening these skills. Graduates emerge not only knowledgeable, but prepared for the job market. Engagement Our students have been embracing these opportunities. Six MBA/Msc teams developed their A4S videos, hoping to reach the final in Canada early in 2025, and three teams out of nine reached the national UBC finals. Additionally, the BISSEM simulation has just finished inspiring another group of MBA students (particularly as the prize for the winning team was tickets to a game at our local Aston Villa premiership football (soccer) club, currently riding high in the league!). Typical feedback from non-Finance specialists is that they suddenly surprised themselves during their participation in the simulation and were reconsidering the options of taking a career in Finance. It seems that our original purposes have been met – increased confidence, passion, deep learning and engagement have been achieved. To interivew Professor Higson, contact Nicola Jones, Press and Communications Manager, on (+44) 7825 342091 or email: n.jones6@aston.ac.uk Elliott, C., Guest, J. and Vettraino, E. (editors) (2021), Games, Simulations and Playful Learning in Business Education, Edward Elgar. Kirillov, A. V., Vinichenko, M. V., Melnichuk, A. V., Melnichuk, Y. A., and Vinogradova, M. V. (2016), ‘Improvement in the Learning Environment through Gamification of the Educational Process’, International Electronic Journal of Mathematics Education, 11(7), pp. 2071-2085. Olczak, M, Guest, J. and Riegler, R. (2022), ‘The Use of Robotic Players in Online Games’, in Conference Proceedings, Chartered Association of Business Schools, LTSE Conference, Belfast, 24 May 2022, p. 79-81. Wiggins, B. E. (2016), ‘An Overview and Study on the Use of Games, Simulations, and Gamification in Higher Education’, International Journal of Game-Based Learning (IJGBL), 6(1), 18-29. https://doi.org/10.4018/IJGBL.2016010102

2 min

Are GCSEs delivering for students and society?

Ahead of the GCSEs results being released on Thursday 21 August Aston University work psychologist, Dr Paul Jones, discusses whether the exams are fit for purpose. He believes that our exam system narrows thinking, and GCSEs emphasise “right answers” and rote recall, creating risk-averse learners who are afraid to fail or think differently. Exams are harming wellbeing GCSEs were designed in the 1980s, when many left education at 16. Today, almost all young people continue to 18, yet they still face a stressful halfway checkpoint that often does more harm than good. Research shows GCSEs are linked to anxiety, sleeplessness and even self-harm. This isn’t about students being “less resilient”, t’s about a system that has prioritised bureaucracy, league tables, and exam statistics over wellbeing. GCSEs don’t prepare students for life Exams reward the ability to memorise and recall under pressure, but the world beyond school demands much more. Employers and universities want young people who can think critically, manage their own learning, collaborate, and adapt. By the time many reach university, students are burnt out from years of high-stakes testing. They often struggle with independence, risk-taking, and curiosity, the very qualities they need to succeed. Over-assessment stifles innovation Our exam system narrows thinking. GCSEs emphasise “right answers” and rote recall, creating risk-averse learners who are afraid to fail or think differently. Innovation, however, requires psychological safety: the freedom to explore, experiment, and make mistakes. In a world where AI can already handle routine tasks like recall and pattern analysis, the human edge lies in breaking moulds, challenging assumptions, and combining knowledge in new ways. Our current system suppresses exactly those skills. Moving GCSEs into the future We need fewer, smarter assessments and a curriculum that builds creativity, resilience, and innovation. Other countries use project-based learning, portfolios, and sampling tests to capture what young people can really do. Wales is already embedding wellbeing and digital skills into its new curriculum. England risks being left behind if it continues to cling to an exam-heavy model designed for a different era. The bottom line Our young people deserve an education that prepares them for life, not just for exams. We should be measuring what really matters: wellbeing, creativity, and the ability to thrive in a fast-changing, AI-driven world. To speak to Dr Jones or for any media inquiries in relation to this please contact Nicola Jones, Press and Communications Manager, Aston University on (+44) 7825 342091 or email: n.jones6@aston.ac.uk

View all posts