Israel Study: What Happens When You Skip Meal Announcements on Your Closed-Loop Insulin Pump?

A study from Israel is offering Type 1 diabetes patients important real-world insights into one of the most common habits that can quietly undermine their insulin pump technology — skipping meal announcements.

What Did the Researchers Study?

Researchers at the Division of Endocrinology, Diabetes and Metabolism at Sheba Medical Center in Tel-Hashomer, Israel, investigated how well the MiniMed™ 780G Advanced Hybrid Closed-Loop (AHCL) system performed when users did not announce their meals to the device. This smart insulin pump automatically adjusts basal insulin and delivers correction doses — but it's designed to work best when users manually enter their carbohydrate intake before eating.

The study followed 14 adults with Type 1 diabetes through three phases: a 5-day supervised in-clinic period, then 90 days at home without announcing meals, followed by 90 days at home with announcing meals. All meals were capped at 80 grams of carbohydrates.

Key Findings — In Plain English

The results were telling. When participants announced their meals, they spent 77.7% of the day in their healthy target blood sugar range of 70–180 mg/dL — the standard Time in Range (TIR) metric recommended by US diabetes guidelines. When they skipped announcements, that number dropped significantly to just 67.5%.

High blood sugar time also increased when meals went unannounced:

• Time spent between 180–250 mg/dL rose from 15.7% to 22.7%
• Time above 250 mg/dL jumped from 3.6% to 7.9%

There was a silver lining: hypoglycemia (low blood sugar) was actually less frequent when meals were unannounced, likely because the pump delivered less aggressive pre-meal insulin. Time in the low range of 54–70 mg/dL dropped from 2.8% to 1.6%.

Good news for snackers: Skipping the announcement for meals containing 20 grams of carbohydrates or less did not meaningfully change blood sugar control. And meals up to 60 grams of carbs did not trigger dangerously high post-meal spikes above 250 mg/dL.

Why an International Perspective Matters

Israel is a global leader in diabetes technology research and has a high per-capita rate of closed-loop pump adoption. Studies from Israeli medical centers like Sheba frequently shape the next generation of pump algorithms used worldwide — including in the United States. This research is especially relevant for the growing number of American patients now using the MiniMed 780G, which received FDA clearance and is one of the most widely used AHCL systems in the US today.

Why This Matters for US Patients

The American Diabetes Association (ADA) recommends a Time in Range goal of at least 70% for most adults with Type 1 diabetes. This Israeli study shows that consistently skipping meal announcements drops TIR below that threshold — from a healthy 77.7% down to 67.5%. That gap represents hours of unnecessary high blood sugar each day, which over time contributes to diabetes complications.

If you use the MiniMed 780G or a similar closed-loop system, the takeaway is practical: announcing your meals matters, especially for anything over a light snack. But forgetting to announce a small snack of 20g carbs or less — think a piece of fruit or a handful of crackers — won't significantly hurt your numbers.

Original Study

Shalit, Minsky, Laron-Hirsh. Unannounced Meal Challenges Using an Advanced Hybrid Closed-Loop System. Diabetes Technology & Therapeutics, 2023. PMID: 37335759. DOI: 10.1089/dia.2023.0139. ClinicalTrials.gov: NCT04479826.