1,5-Anhydroglucitol (1,5-AG), a marker of glycemic control state, is reabsorbed via SGLT (sodium glucose cotransporter)-4 (SLC5A9) at renal proximal tubules. SGLT4 is responsible for reabsorption of mannose, fructose, galactose, glucose, and 1,5-AG. Thus, based on our hypothesis that serum 1,5-AG levels are influenced by diet, we investigated whether eating habits influence serum 1,5-AG levels. In total, 330 subjects (158 males and 172 females) with normal glucose tolerance participated. Relationships between serum 1,5-AG levels and eating habits (intake of meats, fish, soybean products, eggs, dairy products, fruit, vegetables, and salt) surveyed by questionnaire were investigated. Stepwise multivariate regression analysis revealed that habitual intake of dairy products was a significant negative explanatory variable for serum 1,5-AG levels. Serum 1,5-AG levels were lower in subjects with habitual intake of dairy products than in those without. On the other hand, HbA(1C), glycated albumin, fasting plasma glucose, and OGTT 2-h plasma glucose were not different between the subjects of these two groups. In conclusion, habitual intake of dairy products was associated with low serum 1,5-AG levels, independently of plasma glucose levels.