**Background:** Vegetable supply chains in low- and middle-income countries face significant challenges including inadequate cold storage, poor packaging, open-air transport, and limited information sharing between intermediaries. Globally, 42% of fruit and vegetable calories are lost or wasted. In India, vegetable supply averages 266 g/person/day, well below the WHO recommendation of 400 g/person/day. While vegetable production in India doubled between 2002 and 2017, it remains unclear whether existing supply chains can handle increased volumes of perishable foods. This study used a geospatially explicit discrete event simulation model to assess how vegetable supply chains in Odisha, India respond to increased production.
**Methods:** The HERMES Agrifood model simulated the movement of five vegetables—potato, onion, tomato, brinjal (eggplant), and cabbage—through three supply chain levels: village markets (n=5,449), wholesale markets (n=405), and retailers (n=4,689 in a focus region). The model represented the entire state of Odisha (44 million residents, 83% rural). Vegetables entered the supply chain based on block-level production data and exited through consumer purchase or loss (breakage or expiration). The model included bidirectional trade between wholesale markets organized in a three-tier hierarchy (Tier 1: n=4, Tier 2: n=8, Tier 3: n=395). Experimental scenarios multiplied baseline vegetable production by factors of 1.25, 1.5, 2, 3, and 5, assuming no other supply chain changes. Outcomes included demand fulfillment, total loss, and time through the supply chain.
**Key Results:** Under baseline conditions, retail-level demand fulfillment ranged from 67% (potato) to 89% (brinjal). Total postharvest losses ranged from 22% (onion) to 36% (brinjal) of total production. The majority of losses occurred at wholesale markets (12.3–24.4% of production lost in storage) and in transport between wholesale markets (4.9–10.5%). Losses due to expiration far exceeded those from breakage. When production was increased, demand fulfillment improved only modestly or worsened: even at 5x production, brinjal demand fulfillment increased only 4% (from 91% to 95%), while cabbage demand fulfillment decreased 1% (from 74% to 73%). Postharvest losses increased disproportionately: at 1.25x production, additional losses of 4–14% occurred; at 2x production, additional losses of 16–31%; at 5x production, additional losses of 32–49%. Storage losses increased more than transport losses as production rose. More perishable vegetables (tomato, brinjal, cabbage; lifespan 4–7 days) experienced higher losses than less perishable ones (potato, onion; lifespan 15–21 days). Average time through the supply chain was 1.5–1.9 days, with maximum times of 25.3 days (potato) and 7.8 days (brinjal).
**Clinical Implications:** These findings have direct relevance for food and nutrition security policy. Poor diet quality, characterized by inadequate vegetable intake, was estimated to account for 17.6% of deaths in India as of 2017. The study demonstrates that increasing horticultural production without parallel investments in supply chain infrastructure and coordination may exacerbate postharvest losses without improving consumer access. Policies should: (1) address supply chain constraints alongside crop productivity; (2) target interventions to the specific perishability constraints of different vegetables; and (3) invest in information-sharing networks and communication between supply chain actors, not just physical infrastructure like cold storage. The model suggests that even extreme production increases (5x) cannot overcome structural supply chain limitations, and that modest increases (1.25x) already produce disproportionate losses.