Embracing Sustainable and Healthy Eating

Juliet Wilson provides an insightful exploration of sustainable and healthy eating, addressing dietary choices and environmental concerns from a nutrition point of view.

Food production and consumption have a significant impact on the environment, accounting for up to 30% of global greenhouse gas emissions (GHGe)⁽¹⁾. Furthermore, activities associated with food production, including livestock farming, fishing, and food processing, contribute to land conversion, deforestation, water pollution, and biodiversity loss.

The health of the planet is intrinsically connected to our own health. It may not be surprising then that parallel to the climate and nature crisis, humans are experiencing a crisis of their own, illustrated by rising levels of non-communicable diseases and obesity.

We must commit to dietary change to meet climate, nature, and health targets. However, the complexity of balancing sustainability objectives, healthy eating advice and trends towards digital personal nutrition makes it difficult to know how to prioritise change. This article aims to discuss and unravel the main principles of a healthy and sustainable diet (HSD) to enable individuals to make meaningful, informed choices that will improve their health, protect nature, reduce climate change and support positive societal outcomes.

Sustainable food systems (SFS) aim to ensure resilience and reliability of the economic, social and environmental factors required for food security and nutrition. Current dietary patterns cause environmental pollution and are resource intensive, resulting in growing pressure on key planetary boundaries that preserve the integrity of our environment.

At the final stage of the food system, sustainable food principles are presented as relatable, navigable actions for the consumer. Actions include reducing foods associated with the highest greenhouse gas emissions in their production and swapping in foods associated with lower carbon emissions. Therefore, swapping animal products and for plant-based products sit at the core of a sustainable eating pattern.

Healthy diets encompass dietary goals that define nutrient adequacy, optimal intakes of specified food groups and dietary patterns. Defining a healthy diet is complex, as they are embedded in unique historical, religious, social, cultural and economic contexts and are thus very diverse.

A healthy diet is beneficial to health and disease prevention, typically non-communicable diseases (NCDs) such as cardiovascular disease, cancer, chronic respiratory disease and diabetes. The incidence of NCDs has rapidly increased globally, and estimates suggest they account for 74% of all deaths globally. Dietary risk factors are a major determinant of NCD⁽³⁾.

Personalised Nutrition (PN) is one of today's buzzwords. However, the concept of PN is not new. Traditional nutritional consultations compile anthropometry measures, medical history, pathology results, clinical observations, and lifestyle to create a personalised plan for the patient. Therefore, the concept of PN is not new. The recent introduction of digital personalised nutrition shows promise, but at the current time, it is unregulated and influenced by commercial business models.

Digital PN advice is broadly based on mainstream healthy eating guidelines (which is reassuring) but does not include sustainability guidance. Furthermore, testing techniques, such as continuous glucose monitoring, are plastic-based, and functionality is dependent on valuable resources, all of which go straight to landfill. The healthcare system in the UK is the single highest user of single-use plastic in Europe, posing the question of whether we should voluntarily add more plastic to that burden?⁽⁴⁾.

In this context, the concern is whether PN diets are distracting people from the urgency of incorporating sustainable change into their daily lives.

There's a great deal of focus on the environmental and health impacts of consuming animal-sourced food. This is a consequence of the association of these foods with high GHGe and considerable land and water use, as well as a linear increase in the incidence of bowel cancer (processed meats are a probable cause of cancer)⁽¹⁰⁾.

However, red meats (beef, lamb and pork) provide adults with significant percentages of dietary iron (27%), calcium (46%), iodine (61%) and zinc (54%) and therefore make a valuable contribution to nutritional intakes in UK diets⁽¹¹⁾. Furthermore, sub-optimal intakes of several nutrients, such as iron and vitamin D, exist across the population, especially in children aged 11-18 years. This raises the concern that coupling dietary restrictions with existing low intakes of some nutrients could increase the risk of nutrient deficiencies in some individuals.

People with a high meat intake should reduce their red and processed meat consumption to below 70g/day. This reduction could lower their carbon emissions by 22% if intakes are reduced to 50–99 g/day or by 39% if reduced to <50 g/day⁽¹²⁾. The EAT-Lancet Commission suggest that as red meat is both non-essential and associated with adverse health outcomes, optimal intakes may be 0 g/day when replaced by a diverse plant-based diet⁽³⁾. Vitamin B12 is not typically found in plant-derived foods and should be supplemented⁽¹²⁾. Based on risks to health and sustainable gains, the recommended intake is between 0 – 70g/day, depending on individual nutritional needs and preferences. However, 70g/day is an upper intake, not a target intake.

Unlike red meat, poultry has no association with adverse health outcomes and therefore, guidance is to minimize environmental impact by maintaining current intakes or reducing where possible.

A brief internet survey across the leading supermarket chains suggests that an average chicken breast weighs approximately 150g, a sirloin steak weighs 225g, and a portion of mince about 125g. The weekly red meat upper threshold of 490g/week (70g/day) could allow for two portions of lean minced meat and a steak. Processed meats (bacon, ham, sausages, burgers, chorizo etc.) should be avoided, as these foods are both a burden to the planetary health and associated with adverse health outcomes.

Practical suggestions to make a portion of red meat go further include halving the amount of red meat and adding beans (butter beans, chickpeas, cannelloni, kidney beans etc.) to a recipe, a tagine-type meal, for example. This meat/bean hybrid will ensure that protein intakes are not compromised. It is often cheaper and more sustainable to choose lesser-known cuts of meat, such as flank or hanger steaks. Better still, replace some of your usual meat-based meals with other plant-based protein sources such as tofu, tempeh, edamame, amaranth and quinoa.

Although dairy products have a lower environmental impact than meat, they compare unfavourably to most plant-based foods. Countering high GHGe dairy products provide essential nutrients, including calcium and iodine. As such, they are promoted for bone health and fracture prevention. Current recommendations for calcium intakes are 700 mg/day⁽¹³⁾, which aligns with updated guidance^{(8, 9)}. For health requirements, 350-500 grams of milk and dairy products/day, in combination with a varied diet, will achieve adequate intakes of calcium, iodine and vitamin B12. Those individuals with low intakes of milk and dairy are encouraged to consume fortified plant-based alternatives and calcium, iodine-rich foods. However, even fortified versions may not provide sufficient iodine and therefore, iodised salt and seafood are recommended⁽¹⁴⁾. Cheese, particularly hard cheeses, rank highly for GHGe and advice is consistent for lowering cheese intakes^{(8, 9)}.

On balance, the environmental impact and provision of essential nutrients from dairy are considered sufficient to justify the environmental impact.

A third of monitored global fish stocks are overfished, while over 60% are fished to the maximum sustainable yield. As a result, seafood stocks need to be carefully managed to avoid exploitation and reduce pollution from seafood farms^{(14, 15)}.

In the UK, 80% of the fish we eat is from just 5 species; cod, haddock, salmon, tuna and prawns. Choosing less intensively fished species can help improve diversity.

The following guidance is offered⁽¹⁵⁾.

1. Buy wild fish that is certified by the Marine Stewardship Council (MSC), who ensure that fish is well-managed and sustainably sourced.

2. Purchase farmed fish that is certified by the Aquaculture Stewardship Council (ASC)

3. Eat 2 portions of fish a week, one of which should be an oily fish.

4. Eat a diverse range of fish, for example coley, hake, pollock and herring.

The UK population currently average about 299g of fruit and vegetables per day, less than the 5-a-day guideline (400g/day). Currently only 32.5% of adults aged 16 and over eat 5 or more portions of fruit and vegetables⁽¹¹⁾, well below the target intake of 430g required to meet health and sustainability aims⁽⁹⁾. Meeting fruit and vegetable intake targets will be a significant increase for many.

The Importance of Diversity: Globally 75% of the global food supply comes from only 12 plant species. This dietary monotony is linked to a decline in diversity, threatening the resilience of our food system. Furthermore, the coloured pigments in plants, such as flavonoids and carotenoids, are often active compounds associated with health benefits, so a lack of dietary diversity likely reduces health benefits. Years ago, children were encouraged to eat a ‘rainbow of colours’ - this approach is as beneficial today as it was then.

Increasing wholegrain grains, legumes and pulses is recommended to provide protein and help offset lower meat intakes. They also contribute to fibre and energy requirements.

Many nutritious fruits and vegetables have historically been discarded and sent to landfills simply because they were misshapen and ‘ugly’. Mishappen products are cheaper, equally nutritious and help to reduce food waste. So, buying a funny-shaped carrot is a triple win.

The WWF estimates that globally 30% of food produced is wasted. Food waste represents a significant loss of land, water and energy and estimates suggest that losses equate to sufficient food to feed two billion people, twice the number of undernourished people across the globe.

UK households are responsible for approximately 70% of food waste. In fact, according to the Waste and Resources Action Programme (WRAP), the UK throws away around 9.52 million tonnes of food waste a year at a cost to UK householders of £750. The environmental and human cost of food waste is not sustainable or ethical. It is important we change our shopping and consumption behaviours to help decrease food losses across the UK⁽¹⁷⁾.

The foods most commonly wasted in the UK are fresh vegetables, salad, cheese, eggs, bread and fruit – refer to Figure 3.

Our current food systems contribute to 25-30 % of global greenhouse gas (GHG) emissions, occupy ~50 percent of the non-ice land area, cause aquatic pollution and drive losses in biodiversity. Simultaneously, many of us are suffering from poor health as a result of poor dietary choices, and over 800 million individuals are undernourished. Things have to change for us to reach international sustainability targets and transition into a more environmentally sustainable and healthier way of life.