Effect of temporal distribution of food intake and chronotype on glycemic control in subjects with type 2 diabetes

The objectives of this study were to discover ways to operationalize temporal distribution of food intake and to determine if there was an association between 24-hour temporal distribution of energy intake and glycemic control in patients with type 2 diabetes after controlling for demographic, sleep and circadian variables. Adults with type 2 diabetes, excluding shift workers, participated in a structured interview and completed questionnaires about their diabetes history and sleep. A validated construct was used to calculate mid- sleep on free-days as an assessment of chronotype. One-day food recalls were used to determine food intake, portion sizes and timing of eating events, from which 24-hour temporal distribution of macronutrient intake was assessed. Hierarchical linear regression was used to determine if temporal distribution of intake was significantly associated with glycemic control, measured by HbA1c.;The sample included 194 subjects with type 2 diabetes. Hierarchical regression analyses adjusting for demographic variables and chronotype found percent of total grams carbohydrate and percent of total grams fat consumed at dinner were positively associated with HbA1c (p<0.05), while total calorie intake and percent of total grams protein consumed at breakfast was negatively associated with HbA1c (p<0.05). Hierarchical regression analyses adjusting for demographic variables and chronotype also found breakfast skipping and consuming less than the median percent of total calories from snacks were positively associated with HbA1c (p<0.05).;These results suggest dietary intake which decreases as the day progresses may be associated with improved HbA1c, which is in contrast with the commonly endorsed nutrition recommendation of "consistent carbohydrate" intake throughout the day. Furthermore, these results suggest breakfast skipping may be associated with a higher HbA1c. Nutrition counseling in order to help patients to decreases carbohydrate and fat intake as the day progresses as well as to incorporate breakfast may be beneficial as these factors may be associated with an improved HbA1c.