Nine lean, healthy women (aged 18-42 years) were randomly assigned to consume their normal diet on six occasions per day or to follow an irregular meal frequency pattern (three to nine meals per day) for two weeks. After a two-week washout period, each participant consumed the alternate diet for an additional two weeks. During the irregular diet, the women consumed their usual diet sequentially on seven, four, nine, three, five, eight, six, five, nine, eight, three, four, seven, and six occasions per day (average, six per day). Fasting glucose and serum insulin levels were not affected by meal frequency, but peak insulin and area under the curve of insulin responses to a high-carbohydrate test meal were higher after the irregular than after the regular eating pattern (p < 0.01). The irregular meal pattern was associated with higher fasting total (p < 0.01) and LDL (p < 0.05) cholesterol levels.

Comment: These results suggest that eating irregularly produces a degree of insulin resistance and higher cholesterol levels, compared with regular eating. Diabetes and heart disease can now be added to gambling addiction as potential consequences of variable-interval reinforcement.

Farshchi HR, et al. Regular meal frequency creates more appropriate insulin sensitivity and lipid profiles compared with irregular meal frequency in healthy lean women. Eur J Clin Nutr 2004;58:1071-1077.