Eating fast leads to insulin resistance: Findings in middle-aged Japanese men and women

Objective To examine relationships between speed of eating and insulin resistance. Methods Cross-sectional study of 2704 male (mean age and BMI: 48.2 y and 23.3 kg/m2) and 761 female (46.3 y and 21.8 kg/m2) non-diabetic Japanese civil servants, 75% clerical, and 25% manual laborers, using a two-part questionnaire on life-style factors and diet history with self-assessment of categorical speed of eating and energy intake over a 1-month period. We measured BMI, blood glucose and insulin concentrations and calculated insulin resistance using the homeostasis model assessment of insulin resistance: (HOMA-IR). Results BMI correlated with eating rate in both sexes, and with daily energy intake in men. Multiple regression analysis of log HOMA-IR by categorical speed of eating, adjusting for age, energy intake and lifestyle factors showed a statistically significant gradual increase in HOMA-IR with increases in relative eating rate in men (p < 0.001, for trend) and in women (p < 0.01). Adjusting for BMI, this positive relationship appeared only in men (p = 0.03). Conclusions Our results suggest that eating fast is independently associated with insulin resistance in middle-aged Japanese men and women.