Sustainability of Different Diets (HL) (DP IB Environmental Systems & Societies (ESS))

Sustainability of Different Diets

• Factors that affect a diet's sustainability include:

  • Food production methods

  • Transport of food

  • Farming techniques

  • Societal eating habits

Supply chain efficiency

• Length of the supply chain:

  • A longer supply chain usually increases environmental impact

  • Food sourced locally has fewer 'food miles' (distance from farm to plate)

    • This reduces fuel use and carbon emissions

  • Shorter supply chains reduce waste by minimising handling and storage time

• Environmental impact of imports:

  • Foods imported from distant countries require transportation

    • This is often by plane, ship, or truck

  • This transportation emits greenhouse gases, contributing to climate change

Year-round food supply and food miles

• Year-found availability of food:

  • Many consumers expect continuous availability of foods, e.g. fresh fruits, in all seasons

  • This requires importing goods from countries where they are in season, increasing food miles

    • E.g. out-of-season strawberries shipped from across the world have a higher carbon footprint than local, in-season produce

    • Tropical fruits such as bananas, pineapples, and avocados are often sourced from distant locations

Meat consumption and cultural shifts

• Environmental cost of meat:

  • Meat production has a high environmental impact due to land, water, and energy needs

    • E.g. compared to plant-based foods, producing 1 kg of beef can require 15 times more water

    • Cattle also release methane, a potent greenhouse gas, during digestion

• Shifts in meat consumption:

  • In some societies, there is a growing trend to reduce meat consumption

    • This is for environmental and health reasons

  • Many people are adopting 'flexitarian' diets or 'meatless' days

    • This is often to reduce their personal environmental impact from meat production

Rise of veganism and plant-based diets

• Growing popularity of plant-based diets:

  • Plant-based diets are seen as a more sustainable alternative, as they rely less on animal agriculture

  • Focusing on vegetables, grains, and legumes:

    • Reduces land and water use

    • Lowers greenhouse gas emissions

    • Conserves biodiversity

• Nutritional balance:

  • A well-balanced plant-based diet can still meet nutritional needs whilst also being more sustainable

Planetary Health Diet (PHD)

• Definition and goals of the PHD:

  • The Eat-Lancet Commission was responsible for developing the Planetary Health Diet (PHD).

    • It is a guide for sustainable and healthy eating

  • This diet balances human health with the need to conserve natural resources and reduce environmental damage

  • It emphasises vegetables, fruits, whole grains, nuts, and a limited amount of animal products

    • E.g. limited amounts of red meat and dairy

• Benefits of the PHD:

  • Aims to reduce greenhouse gas emissions by shifting dietary habits

  • Supports biodiversity and soil health by reducing the need for monoculture farming, which can degrade land

  • Aligns dietary needs with planetary limits

    • Aims to provide the global human population with enough nutrients without exceeding planetary boundaries

Awaiting image: Planetary health diet

Image caption: A 'planetary health plate' helps to visualise the different components of the Planetary Health Diet