Energy market turmoil due to the Russian-Ukrainian war increased global fuel/food prices. While risks to energy and food security have been suggested, little research has documented impacts for the most vulnerable. During September-October 2022, surveys were administered to 701 households using pay-as-you-go liquefied petroleum gas (PAYG LPG) for clean cooking in an informal settlement in Nairobi, Kenya. Paired t-tests compared PAYG LPG consumption/payment behaviors before (July-October 2021) and during a >15% inflationary food price period (July-October 2022). Three-quarters (74%; n=520) of all households and 94% of food insecure households (n=393; 54% of sample) changed their dietary behavior (changed foods cooked, skipped more meals, and/or reduced PAYG LPG consumption) in 2022. Between July-October 2021 and 2022, PAYG LPG prices increased by 16% (214 Kenyan Shilling (KSh)/kg ($1.53USD/kg) to 249 KSh/kg ($1.78USD/kg) and households reduced their monthly PAYG LPG expenditure by 79% (856 KSh ($6.07USD) to 184 KSh ($1.31USD)). Although 97% of participants continued using PAYG LPG in July-October 2022, average consumption declined by two-thirds (0.82 to 0.27 kg/capita/month; difference(paired-t):-0.28 95%CI:[-0.36,-0.21]). Higher food and LPG prices in 2022 led to substantial declines in food security and LPG consumption in an informal urban settlement, highlighting increased obstacles to achieving the Sustainable Development Goals.