Insulin is the hormone that moves sugar from your blood into your cells. When cells respond to it less effectively — insulin resistance — the body has to produce more insulin to keep blood sugar in range. Over time, that can lead to prediabetes and type 2 diabetes.
Why midlife raises the risk
- Estrogen helps insulin work. As it falls, insulin sensitivity tends to decline.
- Fat shifts to the abdomen. Visceral fat is closely linked to insulin resistance.
- Muscle declines. Muscle is the body’s biggest consumer of blood sugar; less muscle means less capacity to clear it.
- Sleep suffers. Even a few nights of poor sleep measurably reduce insulin sensitivity.
How common is it?
In the US, more than a third of adults have prediabetes, and most don’t know it. Because there are usually no symptoms, testing is the only way to find out.
Getting tested
Ask about a fasting glucose or HbA1c test, which reflects average blood sugar over about three months. An HbA1c of 5.7–6.4% indicates prediabetes; 6.5% or higher indicates diabetes.
What helps
Strength training and walking. Muscle contraction moves sugar into cells even without insulin. A 10–15-minute walk after meals can noticeably lower post-meal blood sugar.
Fiber and protein with carbohydrates. Pairing carbs with fiber, protein and fat slows the rise in blood sugar. Whole grains, beans and vegetables beat white bread and sugary drinks.
Limit sugary drinks and refined carbs, which cause the sharpest spikes.
Sleep. Treating night sweats and insomnia supports metabolic health too.
Modest weight loss. For people with prediabetes and overweight, losing 5–7% of body weight with increased activity cut the risk of developing type 2 diabetes by more than half in the landmark Diabetes Prevention Program.
A note on glucose monitors
Continuous glucose monitors are increasingly marketed to people without diabetes. They can be interesting, but normal post-meal spikes in healthy people aren’t a cause for concern, and the evidence for using them to guide diet in non-diabetic people is limited.