The amount and type of food consumed impacts glycemic response and insulin needs of people with type 1 diabetes (T1D). Day to day variation in types of foods consumed or diet quality may acutely impact glycemic levels and insulin needs within an individual with T1D. As part of the Type 1 Diabetes Exercise Initiative (T1Dexi), we examined the impact of overall daily diet quality on glycemic control. Diet quality was assessed by the Healthy Eating Index-2015 (HEI) where a score of 100 indicates highest quality diet characterized by intake of more vegetables, fruits, and whole grains and less intake of saturated fat and added sugar. Dietary intake was captured on up to 12 different days per participant during the one-month study via food photography with the T1Dexi app. Food photos were analyzed for nutrient intake by the Remote Food Photography Method. Mean HEI score for all participants was 57, similar to the general US population. Each day of dietary intake was classified as low (HEI≤57) or high (HEI>57) within a participant and only participants with at least two low and two high HEI days were included in the analysis. CGM and insulin metrics were compared using a linear mixed effect model with a random subject effect. Participants (n=223) were 19-68 years (37±14 years), 76% identified as female, had a mean HbA1C of 6.6±0.7 and a mean body mass index of 25.1±3.6. On high HEI days (mean score: 66±4), total time in range (70-180 mg/dl) was greater (77.2±14% vs 75.7±14% p=0.01), while time above 180 mg/dl (19±14% vs 21±15%, p=0.01) and mean glucose (143±22 vs 145±22 mg/dl, p=0.02) were lower compared to low HEI days (mean score: 47±5). Total daily insulin dose was lower on high HEI days (0.52±0.18 vs 0.54±0.18 U/kg/day p=0.01). Higher diet quality correlates with improved glycemia and lowered insulin needs during that 24-hour period of time within an individual T1D participant but the impact of diet quality was smaller than the impact of exercise and represents an incremental improvement among well-controlled subjects.

Disclosure

M.B.Gillingham: None. T1dexi study group: n/a. C.Marak: None. P.Calhoun: None. K.E.Neubig: None. S.R.Patton: None. J.R.Castle: Advisory Panel; Novo Nordisk, Zealand Pharma A/S, Research Support; Dexcom, Inc., Stock/Shareholder; Pacific Diabetes Technologies. P.G.Jacobs: Board Member; Pacific Diabetes Technologies, Other Relationship; Pacific Diabetes Technologies, Research Support; Dexcom, Inc. R.L.Gal: None. C.K.Martin: Board Member; EHE Health, Wondr Health, Other Relationship; ABGIL, Research Support; Pack Health, Evidation Health, Lilly, WW International, Inc.

Funding

The Leona M. and Harry B. Helmsley Charitable Trust; Verily Life Sciences; Dexcom, Inc.

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