As rates of obesity, heart disease and type 2 diabetes continue to soar, “What should I eat?” has become one of the most important questions of the 21st century. As a doctor specializing in the diagnosis and treatment of digestive health problems, my patients ask me this question all the time. I believe that they deserve evidence-based answers. Each one of us knows intuitively that food can play a vital role in helping us to improve our health, optimise our quality of life and even to heal and recover from illness. The scientific evidence shows that this is absolutely true. Food is medicine. To maximise your chances of health right now and into the future, to reduce your risk of chronic illness and to add healthy years to your life, you must start with the food on your plate.
After years spent examining the research on diet, nutrition, gut-health and overall health, I am convinced that the more plants and the fewer processed foods on our plates the better. The logical conclusion? A wholefood, plant-based diet. A diet that is built from the nutritious foods that humans have thrived on for centuries – fruits, vegetables, beans, wholegrains, nuts and seeds – can produce incredible benefits in both preventing chronic disease and restoring true health. Whether we are aiming to prevent or treat heart disease, obesity, type 2 diabetes, irritable bowel syndrome, Crohn’s disease, digestive cancers, or any of the diseases that have become so common in the 21st century, a plant-based diet has something to offer. I now start conversations with my patients by asking about the foods they eat each day. By putting more plants on their plates, I have seen individuals of all ages improve both their gut health and overall health, lose weight, improve their mood and even reverse long-term illness.
A nutrient-rich approach to food
A plant-based diet has been consistently rated as one of most nutrient-rich dietary patterns available to humans, meaning that most of the common deficiencies that drive poor health are far less likely to occur. A healthy plant-based diet contains more fibre, folate, vitamins A, C and E, thiamine, riboflavin, magnesium, healthy oils, copper and iron than a diet that includes meat and dairy.
Disease prevention
The weight of scientific evidence overwhelmingly favours a whole-food, plant-based diet as the optimal choice for human health and longevity. People who describe their diet as “vegan” or “plant-based” are 50% less likely to develop heart disease and 70% less likely to develop type 2 diabetes. In contrast, adding just 100g of meat to your plate each day may increase your chances of a diagnosis of type 2 diabetes by almost 50%.
In Britain and other countries that depend upon the meat-heavy, fibre-deficient Standard Western Diet, we tend to view chronic illnesses and frailty as inevitable parts of aging. They are not. Decades of research show that most cases of heart disease, Type 2 diabetes, poor digestive health, and many cancers can be prevented by a healthy lifestyle that includes a diet built around plants.
In 2019, one of the world’s leading medical journals, The Lancet, commissioned an international panel of scientific experts to answer an important question: What should we eat to be healthy? Their evidence-based answer: a plant-based diet. A global shift to a diet dominated by fruits, vegetables, wholegrains, and legumes – also known as a “whole food plant-based diet” – could prevent 12 million unnecessary deaths per year. Not to mention hundreds of millions of visits to emergency rooms, coronary angiography suites, and chemotherapy day-units.
Why I want you to max out your plant diversity!
There are more micro-organisms living within each of our digestive systems than there are trees on planet Earth or stars in the Milky Way. These microscopic bacteria, archaea, viruses and yeasts make up your gut microbiome, which contains 10 times more cells and 100 times more genetic material than the rest of your body combined. As you embark on your plant-based health revolution, the friendly microbes of your gut microbiome will become your crucial allies. Between 2012 and 2017 a team of US-based researchers set out to discover the factors that influence the health of the human gut microbiome in the industrialised world. They completed a detailed analysis of more than 11,000 volunteers, most of whom lived in the UK, the USA and Australia. The results of what became known as the American Gut Project reveal that when it comes to food, the number one predictor of a healthy gut microbiome is the diversity of plants in your diet! Participants who ate more than 30 different plants per week had unique fibre-loving bacteria that just weren’t found in people on a plant-deprived diet. Among the 11,000 volunteers who took part, fewer than 1 in 250 were hitting that magic number of 30 different plants per week. I’m not asking you to eat thousands of different fruits, vegetables, legumes and wholegrains, but I am strongly suggesting that we can all benefit from increasing the diversity of plants in our diets. Further research has shown that vegans really do have better gut microbial health! Try it for a week. Keep a running total for each meal and snack to find out how many plants your microbes are getting to ferment. Can you reach more than 30?
COVID-19 and potential future pandemics
The coronavirus pandemic has placed a grim spotlight on just how common poor underlying health has become. In the US, heart disease now affects more than 1 in 12 working adults, and more than 1 in 5 have been diagnosed with multiple long-term medical conditions. In the UK, over four million people are now living with type 2 diabetes, a condition that barely existed fifty years ago.
To date, COVID-19 has cost the UK more than 250,000 lives. As our health service finds ways to recover from the impact of coronavirus, it’s important that we each consider what we can do to help prevent another zoonotic pandemic. In July 2020, the United Nations recognised the consumption of animal protein as the most important driver of new diseases leaping from animals to humans. Our current dietary pattern requires that we raise more than 70 billion land animals every year. The great majority are kept in cramped and unsanitary conditions that make the emergence of new diseases like COVID-19 and SARs almost inevitable.
Climate collapse
Rapid climate change remains the most substantial risk to human health in the 21st century. If the 58 million meat-eaters in the UK went plant-based for one year, it would reduce CO2 emissions by 65 million tonnes. This annual CO2 reduction would exceed that of making every car in the UK electric, of stopping every flight in and out of the country, and of shutting down every fossil fuel power station currently operating. Deciding to eat more meals without meat and dairy is a powerful change we can all make to help avert the worst possible outcomes of the global climate emergency.
This article is adapted from ‘The Plant-Based Diet Revolution: 28 Days to a Happier Gut and a Healthier You’, by Dr. Alan Desmond with recipes by Bob Andrew. Available now from all good bookstores!

Dr. Alan Desmond is an NHS Consultant Gastroenterologist who is dedicated to educating the public on the health benefits of a whole-food plant-based diet. Based in Devon, he is a sought-after speaker and has featured on several well-known podcasts, including “Deliciously Ella” and “The Doctor’s Kitchen”. Dr. Alan has also written for the Sunday Telegraph and appeared on Virgin Radio’s Chris Evans Breakfast Show.
He shares plant-based meal inspiration alongside the latest news on nutritional science and gut health on Instagram @dr.alandesmond and at twitter.com/DrAlanDesmond

Links and further reading:
1. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems Lancet. 2019. Summary available at: https://eatforum.org/content/uploads/2019/07/EAT-Lancet_Commission_Summary_Report.pdf
2. Beyond meatless, the health effects of vegan diets: findings from the Adventist cohorts. Nutrients. 2014;6(6):2131–2147. Published 2014 May 27. doi:10.3390/nu6062131
3. Coronary heart disease mortality among Seventh-Day Adventists with differing dietary habits: a preliminary report. Am J Clin Nutr. 1978;31(10 Suppl):S191–S198. doi:10.1093/ajcn/31.10.S191
3. Vegetarian dietary patterns and mortality in Adventist Health Study 2. JAMA Intern Med. 2013;173(13):1230–1238. doi:10.1001/jamainternmed.2013.6473
4. Association between dietary meat consumption and incident type 2 diabetes: the EPIC-InterAct study. Diabetologia. 2013;56(1):47–59. doi:10.1007/s00125-012-2718-7
5. Preventing the next pandemic – Zoonotic diseases and how to break the chain of transmission. The United Nations Environment Programme, published 06 July 2020
Available at: https://www.unep.org/resources/report/preventing-future-zoonotic-disease-outbreaks-protecting-environment-animals-and
6. Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK. Clim Change. 2014.
Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4372775/
7. An Answer to Everything: 200 Infographics toexplain the world. Bloomsbury, 2022. ISBN 978-1-5266-3364-4