by Lauren
(New York)
QUESTION: I sometimes have a fasting blood sugar of 95 mg/dL, then I do not eat for a few hours and test again and it is 116 mg/dL. Why does my blood sugar rise when I have not eaten? Can my menstrual cycle affect blood sugar? I have not been diagnosed with diabetes, but I sometimes see higher readings. After meals my glucose lately has not gone above 127 mg/dL while following a low-carb diet. I am 27, about 100 pounds overweight, and have already lost 20 pounds. Can exercise and diet help me reach normal levels, or am I destined to develop diabetes? Can stress also raise blood sugar?
Yes, blood sugar can rise even when you have not eaten because your liver releases glucose between meals. Stress hormones, poor sleep, illness and normal hormonal changes can also affect readings.
Your menstrual cycle may cause small glucose changes in some women, and stress can raise glucose even in people who do not have diabetes.
Your home readings do not diagnose diabetes. Because you are significantly overweight and occasionally see readings above 100 mg/dL, I recommend a laboratory fasting glucose and HbA1c.
Answer by Dr. Albana Greca, MD, MMedSc
Hello Lauren,
You are not destined to develop diabetes. Your weight increases your risk, but your 20-pound weight loss is already an important step. Continued healthy eating, activity and further gradual weight loss can improve insulin sensitivity and reduce your future risk.
Food is not the only source of glucose in your blood. Between meals, your liver releases stored glucose to keep your brain and body supplied with energy.
Hormones such as glucagon, cortisol and adrenaline influence this process. This is why a reading can rise from 95 to 116 mg/dL even when you have eaten nothing.
Home glucose meters also have normal measurement variation, so small differences between readings should not be overinterpreted.
If 116 mg/dL were a properly performed laboratory fasting glucose, it would fall within the prediabetes range. A home meter alone cannot diagnose prediabetes.
| Fasting glucose | Interpretation |
|---|---|
| Below 100 mg/dL | Normal |
| 100–125 mg/dL | Prediabetes range |
| 126 mg/dL or higher | Diabetes range when confirmed |
See our guide to normal fasting blood sugar levels.
Readings around 127 mg/dL or below after meals are reassuring, although interpretation depends on exactly when you test.
Good after-meal readings do not completely rule out prediabetes because fasting glucose, after-meal glucose and HbA1c measure different parts of glucose control.
Learn more about blood sugar levels after eating.
Yes. Changes in estrogen and progesterone may temporarily affect insulin sensitivity. Some women notice slightly higher glucose in the days before their period, while others notice no difference.
If you are monitoring, record your cycle date along with glucose readings. This may show whether you have a repeatable pattern.
Yes, even if you do not have diabetes. Stress hormones such as cortisol and adrenaline can signal the liver to release additional glucose.
In people without diabetes, insulin usually brings glucose back down efficiently. In insulin resistance or diabetes, the increase may be larger or last longer.
No. Being overweight increases your risk, but type 2 diabetes is not inevitable.
Your 20-pound weight loss is meaningful even if you have not yet noticed a dramatic change in individual meter readings. Blood glucose naturally fluctuates, so progress should not be judged from a single number.
Continue with sustainable habits rather than an extreme diet. You do not need to eliminate all carbohydrates.
The rise from 95 to 116 mg/dL without eating can happen because your liver continues releasing glucose between meals. Stress and menstrual-cycle hormones may also influence readings.
Your weight increases your risk, but your 20-pound loss is a positive step. Rather than trying to diagnose yourself from home readings, I recommend a laboratory fasting glucose and HbA1c so you know where you stand.
Last reviewed: August 2026.
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