Contact between upper and lower posterior teeth is crucial for chewing. However, the influence of posterior occluding teeth loss on protein intake and muscle mass was unclear. This cross-sectional study compared consumption frequency of protein food, amount of protein and relevant micronutrient intakes and muscle mass indices among older adults with different Eichner indices (EI) of posterior occluding teeth loss. Ninety Thai healthy adults were divided into three groups (N=30 each) according EI with statistically comparable characters. Food frequency questionnaire, 4-days diet record, and bioelectrical impedance analysis were used for outcome measurement. Our findings suggested that loss of posterior occluding teeth on both sides was associated with less frequent consumption of meat, nut, egg, fish and dairy products, inadequate intakes of protein (< 0.8 g/kg body weight), iron and vitamin B12, and reduced muscle mass indices in older adults. Future large-scale cohort studies are warranted to confirm these findings.