Why Eating Seasonal Food Is Better — Nutrition, Flavour, Cost and Planet

Freshness and nutritional content are directly related. Vitamins — particularly water-soluble vitamins C and B — degrade rapidly after harvest through oxidation and enzymatic breakdown. A 2012 study in the Journal of Agricultural and Food Chemistry found that spinach stored at room temperature lost 47% of its folate content in just four days. Refrigeration slows but does not stop this process.

Produce transported thousands of miles for out-of-season consumption is typically harvested before full ripeness (to withstand transportation stress), cold-stored for days or weeks, then treated with ethylene gas to ripen on arrival. This process produces fruit and vegetables that look ripe but have not undergone the full flavour and nutrient development that occurs when ripening happens naturally on the plant.

A 2016 study by the University of California found that broccoli, tomatoes and peppers purchased out-of-season (and transported long distances) had significantly lower concentrations of antioxidants, vitamin C and glucosinolates than seasonal equivalents grown locally.

The flavour of a tomato comes from a complex interplay of sugars, acids and volatile aromatic compounds — primarily a family of molecules called C6 aldehydes and alcohols. These compounds develop fully only during vine-ripening, driven by sunlight and heat. A tomato ripened under grow lights in a greenhouse does not develop the same flavour compound profile as one ripened in southern Italian sun in August.

Similarly, stone fruits (peaches, nectarines, plums) develop their characteristic aroma from esters and lactones — compounds that accumulate primarily in the final stages of ripening on the tree. Early-picked fruit lacks these compounds regardless of how it's subsequently stored.

For vegetables, the sweetness of freshly harvested sweetcorn is a well-documented phenomenon — within hours of harvest, sugars begin converting to starch, permanently reducing sweetness. Varieties bred for long transport life are selected for shelf-stability, not flavour.

Food transport accounts for approximately 11% of food-related greenhouse gas emissions globally, according to a 2018 Science study by Poore and Nemecek. While food production itself (especially animal agriculture) dominates food emissions, transport becomes significant for air-freighted produce — flights emit 50x more CO₂ per kilometre than shipping.

Beyond carbon: seasonal, local produce supports farm biodiversity. Farms growing for local seasonal markets typically grow a wider variety of cultivars — heirloom tomatoes, heritage apple varieties, unusual squash cultivars — rather than the handful of high-yield, high-durability varieties that dominate industrial supply chains. This biodiversity matters both for ecosystem health and for food security.

Financially, seasonal produce is almost always significantly cheaper when in season. Peak-season strawberries cost a fraction of out-of-season ones. A market stall in June sells tomatoes at prices that would be unthinkable in February.

Seasonal eating doesn't require radical change — it requires awareness and flexibility. A few practical principles:

**Shop at farmers markets.** The simplest way to eat seasonally is to buy what farmers are actively selling. If a farmer has 20 varieties of squash in October and no tomatoes, that tells you exactly what's in season. The conversation with the grower is also the best source of recipe ideas for unfamiliar produce.

**Learn your seasonal calendar.** Most produce has a peak window of 6–12 weeks. Learning when your favourite ingredients peak in your climate takes one season of attention.

**Embrace the unfamiliar.** Seasonal eating forces you to cook with ingredients you might not choose by default — celeriac in winter, kohlrabi in early summer, quince in autumn. These are often the most interesting ingredients.

**Preserve peak-season produce.** Freezing summer berries, making tomato sauce in August, pickling cucumbers in July — these practices extend seasonal eating through the year.