Report: Diet overhaul could prevent millions of deaths, save planet

Adopting healthier diets worldwide could prevent up to 15 million premature deaths annually while simultaneously shielding the planet from the worst effects of climate change and ecological collapse, a new report has found.

The analysis by the Lancet Commission on Healthy, Sustainable and Just Food Systems, reveals that food systems currently contribute most significantly to five of the nine planetary boundaries — the safe operating limits for humanity. These boundaries include climate change, biodiversity loss, freshwater overuse, land system change, and nitrogen/phosphorus pollution.

Also read: Report: Over half of all hospital deaths now caused by lifestyle diseases

Currently,  food production accounts for around 30 per cent of total global greenhouse gas emissions. However, the report offers a hopeful counterpoint: with urgent and coordinated action, these emissions could be slashed by more than half.

"The evidence is undeniable: transforming food systems is not only possible, it’s essential to securing a safe, just and sustainable future for all," said Johan Rockström, co-chairperson of the commission.

The commission’s findings build on its influential 2019 report, confirming that adopting healthier, more sustainable diets such as the Planetary Health Diet could yield significant benefits. This diet emphasises plant-based foods such as fruits, vegetables, legumes, nuts, and whole grains, while recommending moderate amounts of foods sourced from animals and minimal sugar and saturated fats.

Cultures and traditions

Walter C Willett, the commission’s co-chairperson, stated that such dietary changes “can improve health outcomes everywhere while respecting cultural and regional traditions”. Yet, global diets are currently falling short, characterised by insufficient intake of fruits, vegetables, and whole grains, and an over-reliance on meat, dairy, sugar, and ultra-processed foods in many regions. The commission stresses that a pivot to plant-rich diets would reduce disease risk, increase life expectancy, and dramatically lower the environmental footprint of our food.

In Kenya, the report's finding resonate with growing concerns over dietary habits, food affordability, and the surge in nutrition-related diseases. The country is grappling with a 'triple burden' of malnutrition, where undernutrition, micronutrient deficiencies, and obesity coexist.
 
While traditional staples such as legumes, maize, and leafy greens offer a foundation for nutritious meals, changing food habits and the growing preference for processed, sugary, and high-fat foods have weakened diet quality.

According to a report by the United Nation agencies, fewer than five per cent of Kenyan adults consume the recommended daily servings of fruits and vegetables, and about 77 per cent of households cannot afford a healthy diet as costs have risen by nearly 66 per cent in recent years.

Also read: Why Kenyan youth are increasingly suffering stroke

"We are seeing both extremes — children who are undernourished and adults who are becoming increasingly obese and developing lifestyle diseases," said Judy Kariuki, a Nairobi-based nutritionist. "Much of this is driven by urbanisation and changing eating habits that favour processed foods over traditional, wholesome meals.'

Experts suggest that reviving indigenous foods such as managu (African nightshade), terere (amaranth) and nduma (arrowroot) could enhance health and environmental resilience. This would align perfectly with the plant-rich 'Planetary Health Diet' advocated by the Lancet Commission.

"Indigenous vegetables are not only nutritious, but also climate-smart," added Ms Kariuki. "They require less water and fewer resources, making them ideal for sustainable diets in a changing climate."

Kenya’s National Guidelines for Healthy Diets and Physical Activity promote whole grains, legumes, fruits and local vegetables. However, experts argue that stronger action is needed, from regulating ultra-processed foods to supporting smallholder farmers who grow nutritious crops.

The Lancet report also highlights severe inequalities in current food systems. Fewer than one per cent of people worldwide live in a 'safe and just space', where both human well-being and planetary boundaries are respected. Meanwhile, the wealthiest 30 per cent of the global population are responsible for over 70 per cent of food-related environmental impacts, while over one billion people remain undernourished.

Furthermore, nearly one in three food system workers (32 per cent) earns less than a living wage, reflecting a system that benefits a few while exploiting many.

Analysis suggests that reshaping food systems could generate returns of up to $5 trillion annually through improved health, restored ecosystems and enhanced climate resilience—far exceeding the estimated investment required to drive change, which is estimated to be between $200 and $500 billion.

 [email protected]