Review of the plant-based nutrition and lifestyle medicine news September 2026

This month I cover healthy ageing, dietary fat and prostate cancer, plant-rich meals in hospitals, dairy and health plus more benefits of adding plants to your plate.

Dietary patterns, mortality and life expectancy by frailty status

Readers will already know that dietary risk factors are one of the key determinants of chronic ill health and early death in the UK and globally. Healthy diet patterns are in general high in fruit, vegetables, whole grains, beans, nuts and seeds and low or absent in red and processed meat and ultra-processed foods.

This new study aimed to assess the impact of dietary patterns on life expectancy in participants of the UK Biobank Study, stratifying by frailty status. The study focused on four dietary patterns assessed via a food frequency questionnaire at baseline: alternative Mediterranean Diet (aMED), which assesses intake of foods central to the traditional Mediterranean diet; Dietary Approaches to Stop Hypertension (DASH), designed to prevent hypertension and cardiovascular disease; Plant-based Diet Indices (PDI), which evaluate the quality and extent of plant-based food consumption, including overall (PDI), healthful (hPDI), and unhealthful (uPDI) versions; and Planetary Health Diet Index (PHDI), based on the EAT-Lancet Commission’s recommendations for both human and planetary health. Frailty status was assessed at baseline using five criteria: weight loss, exhaustion, physical activity, walking speed, and grip strength.

After a median follow-up of 13.4 years, participants most adherent to these healthy diet patterns had a significant reduction in mortality. Adherence to the Mediterranean diet reduced mortality by 24%, the DASH diet by 17%, the PDI by 16% and the PHDI by 12%. Even more benefits were apparent in those with greater frailty.

Analysis of individual food components revealed that higher intake of plant-based foods such as whole grains, fruits, vegetables, nuts, and legumes was associated with a lower risk of all-cause mortality, while higher intake of red meat, processed meat, and sugar-sweetened beverages was associated with higher risks. Associations with fish, chicken and eggs were not consistent.

Greater adherence to healthy dietary patterns also predicted for a longer life expectancy. At age 40, greater adherence to the Med diet led to a life expectancy of 46.7 years, the DASH diet 46.1 years, the PDI 45.74 years and PHDI 45.72 years. Greater life expectancy with a healthier diet was seen across all frailty statuses. Women had a longer life expectancy than men, but men seem to benefit the most from adhering to a healthier diet.

Although the study results are not surprising, what it does show is that a healthy diet can improve health and longevity regardless of frailty, with perhaps even more benefits for older, frail people. So the key message has to be – it’s never too late to adopt a healthy diet, including eating more plant-based foods.

It should also be noted that we know the British public on average eats less than one portion of legumes per week and only 17% of adults eat 5 portions of fruit and veg per day. These findings are therefore in the context of a population who are in general not consuming enough of the foods that promote food health. A prior analysis from the same study cohort showed that the consumption of carbohydrate-rich plant-based foods was associated with markers of healthier ageing, whereas animal foods and low-carb diets were associated with adverse effects on markers of ageing.

Vegan diets in healthy older adults

There is still doubt as to whether a fully plant-based or vegan diet is appropriate for older adults, in part because of the traditional thinking that animal protein is more bioavailable and hence should be associated with lower rates of frailty.

This randomised study aimed to ask whether healthy older adults could adopt a vegan diet without compromising protein intake and skeletal muscle mass.

The study had three parallel arms in which 72 healthy older adults aged ≥65 years were randomly assigned to follow 1) a self-selected vegan diet (VEG), 2) their habitual omnivorous diet (OMNI), or 3) a self-selected vegan diet with RE (VEG-RE) for 12 weeks. The primary outcomes was total fat-free thigh muscle volume assessed with MRI. There were a number of secondary outcomes including, muscle volume of the anterior and posterior thighs of the dominant- and non–dominant legs specifically, appendicular lean mass, body mass, thigh muscle strength, thigh muscle fat infiltration (MFI), abdominal subcutaneous adipose tissue, visceral adipose tissue, liver fat fraction, muscle protein synthesis (MPS) rates and dietary intake of energy, macronutrients and essential amino acids consumed per day.

The vegan diet groups were counselled during three nutrition meetings, before and two during the study. Participants were provided with resources, including recipes. To improve compliance, all participants were provided with self-selected commercially available plant-based (VEG and VEG-RE) or animal-based (OMNI) food products every other week.

During the study period there was a significant decrease in protein intake (27g/d) in both the VEG groups compared to their baseline and decreased intakes of essential amino acids (except cysteine). The VEG groups also significantly increased their intake of carbohydrates and fibre (45%). There was no difference from baseline in intakes of energy or fat. This change in dietary intake in the VEG group correlated with a decline in skeletal muscle mass and in lower daily MPS rates. However, this decline was attenuated in the VEG-RE group who were doing resistance exercise twice per week. There was also a difference in change in muscle strength between VEG (~5‒10% strength loss) and VEG-RE (~3‒8% strength gain). The VEG group also lost body mass (-2.9kg) suggesting negative energy balance despite energy intake not changing. This suggests that perhaps absorption of food reduced, in part because of the higher fibre intake.

At first the results may seen alarming and interpreted as a vegan diet is putting older adults at risk of sarcopenia. However, the study does not provide information on the actual dietary intake of participants. What is clear is that shifting from an omnivorous to a vegan diet requires adequate knowledge and skills on how to incorporate high protein foods into the diet. The substantial decrease in protein intake from baseline in the VEG groups suggested that intakes of beans, soya and other meat analogues were insufficient. Yet, when protein intake is adequate, we know that a vegan diet can support muscle protein synthesis and maintain muscle mass and strength just as well as an omnivorous diet, with evidence of potential adaptation to lower protein intakes.

So the cautionary note here is that when older adults adopt a vegan diet, adequate support is needed to ensure they consume enough energy and protein. The study also demonstrates the benefits of resistance exercise, which should be a part of everyone’s routine.

Do vegetarian diets increase the risk of early death?

A rather alarming new study suggests that older adults following a vegetarian diet have an increased risk of premature death. Researchers analysed dietary data and causes of death in adults aged ≥65 years from the Chinese Longitudinal Healthy Longevity Survey (n = 6678) and the US National Health and Nutrition Examination Survey (n = 6305). Those participants following a vegetarian diet (various subtypes of vegetarian diet were defined – pesto-vegetarian, lacto-ovo vegetarian and vegan) or who had transitioned from an omnivorous to vegetarian diet had an increased risk of all cause mortality in the range of 19-52% increased risk.

Although we can’t dismiss study results because they don’t align with one’s values or mission, it’s worth noting a few things about this study. Firstly, vegetarians were identified by the fact that they excluded various animal sourced foods from the diet. There are no data provided on what these participants were actually eating. The numbers of vegetarians in each cohort was very small – 578 in the Chinese cohort and 191 in the US cohort. Therefore the number of deaths during follow-up in each category were tiny – 50 deaths of vegans in the Chinese group and 10 in the US group.

Without knowing anything about diet quality, it is impossible to take any learning away from this paper. We know that meat-free diets can be composed of high intakes of refined grains, sugar and ultra-processed foods or they can be healthy if focussed on minimally processed whole plant foods and thus diet quality is paramount when researching health outcomes We also have no idea what the participants died of.

Overall, the study is worth noting but needs to be put into the context of the rest of the literature we have on meat-free diets. In larger cohorts such as the the EPIC-Oxford study, all-cause mortality is not significantly different from omnivores. In the Adventist Health Study-2, vegans have a lower mortality at age 65 years but this advantage is lost by age 85 years. However, vegans and vegetarians consistently show lower rates of cardiovascular diseases, cancer and type 2 diabetes. I think most people who identify as vegan would be happy to accept these findings and be reassured with the fact that chronic disease risk may be lower albeit with a comparable life-expectancy to omnivores.

Dietary Fat Intake and Mortality Among Patients With Nonmetastatic Prostate Cancer

There is accumulating evidence that healthy habits, including dietary factors, are important after a diagnosis of cancer and can improve survival. There has been a lot of research on dietary factors and prostate cancer, which I have summarised in this article. Essentially, a plant-based diet is associated with lower risk of prostate cancer and improved outcomes following diagnosis.

This new analysis from the Health Professionals Follow-Up Study from the US analysed the impact of fat consumption after a diagnosis of prostate cancer in 4884 men, during a median follow-up of 12.8 years. Dietary data was collected via questionnaires every 4 years.

The results showed that men consuming the most saturated fat had an increased risk of dying from all-causes (24% increased) cardiovascular diseases (42% increase) and other cancers (42% increase). Saturated fat is mostly derived from animal-sourced foods. Replacing 10% of calories from animal fats with plant-based fats and replacing 5% of calories from saturated fats with monounsaturated fats (nuts, avocado, olives/olive oil) was associated with a decrease in all-cause mortality of 16% and 20% respectively. Dietary fat intake was not specifically associated with prostate cancer mortality.

There are no surprises here in that diets high in animal-sourced foods and saturated fat have long being shown to increase the risk of cardiovascular disease, with healthy plant-based diets showing the opposite. The authors conclude ‘This study coupled with prior epidemiologic studies provides evidence-based recommendations for patients and clinicians around dietary fat consumption to improve survivorship outcomes in the clinical setting of non-metastatic prostate cancer.’

Implementing the Planetary Health Diet in a Canadian acute hospital

This is a genuinely important study for all of us working in the institutional diet change space, especially healthcare. It provides some of the strongest real-world evidence to date that plant-rich menus can be introduced successfully in a large acute hospital. In a 700-bed Canadian tertiary hospital, researchers redesigned lunch and dinner menus by replacing higher-impact dishes with newly developed plant-based and lower-emission options (animal-sourced food was still included in the new menu). Plant-based dishes increased from 0% to 39% of first-choice meals, while meat provision fell substantially.

Importantly, the new menu remained nutritionally adequate. Average protein provision was maintained at around 87 g/day, fibre increased from 19.1 to 23.2 g/day, iron content increased, and calcium and folate improved to meet recommended targets. Overall plate waste did not increase significantly, despite concerns that unfamiliar plant-based meals might be rejected. In fact, waste fell significantly for the newly developed pulse, soya and fish dishes compared with their original counterparts.

Uptake was also impressive with the new dishes served to around 67% of hospitalised patients at each mealtime. 84% of surveyed patients rated them positively, and only 5% of those receiving a plant-based dish chose not to try it. The environmental benefits were substantial, with greenhouse gas emissions from catering falling by 39% and land use by 51%.

For our work in the UK with the Plants First Healthcare Coalition, the key message is that plant-rich hospital food is not only feasible, but can be nutritious, acceptable to patients and compatible with reducing waste and emissions. The study also reinforces the importance of chef-led recipe development, cultural relevance, patient feedback and making plant-rich dishes part of the normal menu rather than a marginal special-diet option.

Another study relevant to public sector catering comes from my colleagues at King’s College London, where researchers tested a “root-to-tip” approach to catering, using parts of fruits and vegetables that would normally be discarded during food preparation, such as peels, skins, stalks and seeds, as ingredients in meals.

Thirty-two dishes were co-designed with chefs and introduced across five university food outlets over nine weeks. Examples included an Asian watermelon salad incorporating the rind and a West African peanut stew using unpeeled butternut squash and its seeds.

During the 9-week intervention period, root-to-tip dishes accounted for 36.6% of all hot-meal sales, while among survey participants choosing a hot meal, 62.4% selected a root-to-tip dish. This approach results it each serving containing on average 0.7 g more fibre while generating 39.7 g less food-preparation waste, amounting to 230 kg of avoided waste. Although conducted in a university rather than a hospital, this is highly relevant to the wider public sector. It shows how chefs can think beyond simply replacing animal foods with plants and instead use plants more creatively and completely, improving nutritional value while preventing food waste. Interestingly, taste and health, rather than sustainability, were the strongest drivers of food choice, reinforcing an important lesson for plant-rich public-sector catering: sustainable food needs first and foremost to be delicious, nutritious and appealing.

Dairy and health

I was honoured to be part of this new documentary exposing the truth about dairy. It will be essential viewing for anyone that still consumes dairy. It is also timely to see this new review paper on dairy by Dr Matthew Nagra and colleagues. The summary is that dairy is not required in the diet of humans. Milk is for babies and not needed beyond weaning. The health impacts depend on what it is replacing in the diet. Dairy is certainly better for health than eating red and processed meat and drinking sugar-sweetened beverages. But, we can make a healthier choice. Choosing beans, pulses, soya, whole grains nuts and seeds instead of dairy is better for health.

The authors of the review conclude ‘Health professionals and researchers are encouraged to adopt the comparative perspective offered by substitution analyses, recognising that the health implications attributed to dairy are largely a function of what it replaces, or what replaces it, within the overall dietary pattern, rather than reflecting an inherent property of dairy in isolation.’

There is nothing special about consuming dairy from a cow when it comes to health. Yet is it horrific for the cows trapped in this industry and farming cows is detrimental to planetary health in terms of carbon and methane emission, land and water use and land, air and water pollution. Let’s be true to the evidence and stop promoting dairy as a health food.

Other notable studies this month include a secondary analysis from a randomised study conducted by PCRM showing once again that a fully plant-based/vegan diet reduced dietary energy density by around 30% hence leading to lower energy intake and greater weight loss compared to an omnivorous diet. This is because plant-based foods are high in water and fibre and low in fat, thus increasing food volume without a proportional increase in energy content. This supports satiety and reduces energy intake without having to deliberating restrict calories/portion size. Read more about energy density and weight management in our free resources.

A massive new meta-analysis from Dr Dagfinn Aune and colleagues, including 87 randomised studies, finds that whole grain consumption is associated with a number of cardiometabolic benefits including, lower body weight, waist circumference, IL6 and CRP levels (markers of inflammation), LDL-cholesterol, triglycerides, fasting plasma glucose and systolic blood pressure. Intakes of 60-100g dry weight (∼115–190 g/day fresh weight) or 4–6 servings per day may be the optimal amount.

We now have a plant-based option for enteral tube feeding in hospital. This study shows that Compleat® Plant Protein 1.6, a food for special medical purposes for use under medical supervision, is well tolerated and acceptable to patients requiring tube feeding. The protein source is pea and the product also contains omega-3 fats and vitamin D from algae. This product has the potential to replace dairy-based tube feeds in order to be more inclusive of people who are lactose intolerant/dairy allergic, vegan, and to meet sustainability goals.

Finally, updated school food standards in the UK have removed the requirement to serve meat three time per week. Instead, schools are free to choose between a variety of protein sources, including pulses. There is much more emphasis on serving fruits and vegetables and limiting ultra-processed foods. Plant-based drinks are also considered an acceptable alternative to dairy milk. My main disappointment is the continued allowance of cheese as a protein source, albeit limited to two meals per week. Optional topping cheese on jacket potatoes and pasta are excluded from the weekly limit. Overall, this does leave the door wide open for schools to adopt plant-rich or even plant-exclusive menus.

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