Background <p>Food insecurity is a significant determinant of various health outcomes, including obesity and mental health disorders. To the best of our knowledge, no research has been conducted to examine the relationship between food insecurity and abdominal obesity, sleep-related outcomes, and mood among Iranian older adults.</p> Methods <p>This cross-sectional study comprised 400 older adults, with a mean age and BMI of 63.36 and 28.86&#xa0;kg/m². Dietary intake was evaluated using a validated and reliable 168-item food frequency questionnaire (FFQ). Abdominal obesity was assessed through waist circumference (WC). Sleep-related outcomes, mental health, and mood status were measured using the Pittsburgh Sleep Quality Index (PSQI), the Depression Anxiety Stress Scales (DASS-21), and the Profile of Mood States (POMS), respectively.</p> Results <p>The final model shows that higher levels of food insecurity are significantly linked with poorer sleep quality (<i>P</i> = 0.003), greater symptoms of depression (<i>P</i> &lt; 0.001), anxiety (<i>P</i> = 0.006), and stress (<i>P</i> &lt; 0.001), as well as worse mood (<i>P</i> &lt; 0.001). Additionally, food insecurity is positively associated with increased abdominal obesity and higher body roundness index (BRI) (<i>P</i> = 0.021).</p> Conclusions <p>This study highlights significant associations between food insecurity and both mental and physical health outcomes, particularly through novel anthropometric indices such as BRI and abdominal obesity. These findings emphasize the critical need to address food insecurity within public health frameworks. By identifying these links, the study provides valuable evidence for developing targeted interventions and policies aimed at reducing the burden of food insecurity and its related health consequences in affected populations.</p>