How Does Insulin Work? Understanding The Hormone That Controls Blood Sugar

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At every Indian festive table this season, from the sweets exchanged on Raksha Bandhan to the ladoos that will arrive with Janmashtami and Ganesh Chaturthi, one hormone is working harder than anyone else at the celebration. It never gets invited, never gets thanked, and most people could not explain what it actually does. Yet insulin decides, quite literally, where every gulab jamun and kaju katli you eat ends up - used as energy, stored for later, or left circulating as a problem waiting to surface.

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Understanding how insulin works matters most in a country where indulgence is written into the festive calendar. India already carries one of the world's largest diabetes burdens, with over 101 million people living with the condition, and much of that comes down to how well, or how poorly, this one hormone does its job.

Gyaan by Ganesh - Making India Win Over Diabetes is an awareness initiative by Sun Pharma, in partnership with the American Diabetes Association, focused on helping Indians better understand, prevent, and manage diabetes through expert-backed information.

The Key That Unlocks Every Cell

Insulin is a hormone made by beta cells in the pancreas, and its job is deceptively simple: it is the key that lets glucose out of the bloodstream and into cells, where it becomes usable energy.

Here is what happens after a festive meal. Carbohydrates - rice, mithai, fried snacks - break down into glucose, which enters the bloodstream and raises blood sugar. The pancreas senses this rise and releases insulin in response. Insulin then travels through the blood and binds to receptors on muscle, fat, and liver cells, signalling them to open glucose transporters and pull sugar out of circulation. Muscles use some of it immediately for energy; the liver converts the rest into glycogen for later; anything left over gets stored as fat.

Without this handoff, glucose simply builds up in the blood instead of reaching the cells that need it.

The Key That Doesn't Always Fit

The system works well under normal conditions. It struggles under festive ones. Research published in Applied Physiology, Nutrition, and Metabolism found that healthy adults who overate for just two weeks saw a marked drop in whole-body insulin sensitivity - the body's ability to respond efficiently to its own insulin. The change happened long before any noticeable weight gain, driven purely by the sustained calorie and sugar load.

"Every time you eat something sugar-heavy, the pancreas has to work overtime to bring glucose back into range. Do that repeatedly over a festival week, and the body's sensitivity to its own insulin can dip within days, not months," said Dr Vishal Agarwal, Consultant Endocrinologist, Dibrugarh, Assam.

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That dip is usually temporary in someone with a healthy pancreas. But in someone already prediabetic or insulin resistant, repeated festive spikes can tip the balance from manageable to diagnosable.

When The Key Breaks Or The Lock Changes

Diabetes happens in two different ways, and insulin sits at the centre of both.

In Type 1 diabetes, the immune system destroys the beta cells that make insulin, so the body produces little or none. Without external insulin, glucose has no way into cells and builds up dangerously in the blood.

In Type 2 diabetes - the form behind the vast majority of India's cases - the pancreas still makes insulin, but cells stop responding to it properly. The pancreas compensates by producing more, working harder and harder, until eventually it cannot keep pace with demand.

Protecting Your Insulin This Festive Season

Doctors do not recommend giving up festive food. They recommend giving insulin less to fight against:

• Eat sweets alongside a meal, not on an empty stomach - protein and fibre slow the glucose spike
• Take a 15-20 minute walk after a heavy meal to help muscles absorb glucose without extra insulin
• Keep meal timings roughly regular, even on celebration days
• Stay hydrated, since dehydration concentrates blood glucose
• Don't skip sleep - even one poor night measurably reduces insulin sensitivity the next day

Dr Agarwal concluded, "Insulin does not announce itself the way a festival does. It works quietly, meal after meal, deciding whether the sugar in your blood becomes fuel or a future problem. Most people only think about it once something has gone wrong. Understanding it now, before the season of ladoos and long nights begins - is what turns festive indulgence from a health gamble into something the body can actually handle."

[Disclaimer: This material is for patient education/awareness purpose only. It does not replace the advice or counsel of a doctor or health care professional. Sun Pharmaceuticals Laboratories Limited (SPLL) makes every effort to provide information that is accurate and timely, but makes no guarantee in this regard. You should consult with, and rely only on the advice of, your physician or health care professional. No part of this may be reproduced, transmitted or stored in any form or by any means either mechanically or electronically without prior intimation to Sun Pharmaceuticals Laboratories Limited (SPLL). SPI-IN-CVD-ZT---08-20260303]

References:

1. https://www.thelancet.com/journals/landia/article/PIIS2213-8587(23)00119-5/fulltext https://pmc.ncbi.nlm.nih.gov/articles/PMC3891585/
2. https://idf.org/managing-diabetes/insulin/
3. https://my.clevelandclinic.org/health/body/22601-insulin
4. https://my.clevelandclinic.org/health/body/22601-insulin