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First Trial of Its Kind: Time-Restricted Eating Tested in Type 1 Diabetes

By the GlycemicWise Data Editorial Team · Published 2026-08-31 · Last reviewed 2026-08-31 · News · 6-8 min read · Dietary reference only

A University of Illinois Chicago randomized trial in Diabetes Care (August 17, 2026) followed 32 adults with obesity and type 1 diabetes for six months: the 8-hour time-restricted-eating group (noon to 8 p.m., no calorie counting) lowered HbA1c by about 0.5 points versus calorie counting, with no increase in severe highs, lows, or DKA.

The First Safety Test

Time-restricted eating has decades of type 2 data and almost none for type 1 — where insulin dosing makes any eating-window change a hypoglycemia question. A UIC team led by Krista Varady randomized 32 adults with obesity and type 1 diabetes to three arms for six months: an 8-hour eating window (noon to 8 p.m.), a 25% calorie deficit, or no change — the first randomized trial of fasting in this population.

The Result

The TRE group finished with HbA1c about 0.5 points lower than the calorie-counting group, and — the part the safety monitoring existed for — no increase in severe hypoglycemia, severe hyperglycemia, or diabetic ketoacidosis. For a population told for decades that irregular eating is risky, the safety signal is the headline.

The Honest Scope

Thirty-two participants, one city, six months, and a specific population (type 1 plus obesity) — the author herself frames it as a first step requiring larger multi-site trials, and anyone changing eating patterns with type 1 needs their endocrinologist adjusting insulin alongside. This is a promising safety-and-efficacy signal, not a protocol.

Window and the Food

The 8-hour window is the same structure the database applies to type 2 time-restricted eating: compress the hours, keep the food quality high. Inside the window, the low-GL pattern — protein anchors, legumes, non-starchy vegetables — matters just as much when the pancreas is absent as when it is struggling; the window changes when you eat, not what earns its place on the plate.

Dietary reference — not medical advice. Information provided for educational purposes.