How much of a rise in blood sugar is too much for you?

My Endocrinologist recommended that I stay below 250

When i was in hospital they took a reading 2 hours after each meal. The nurses were always happy wth 140-145. They told me it was a good postprandial level.

Full disclosure: I entered your question into Copilot. I thought the answer was interesting, but could be slightly different for diabetics. Hope this helps you. You might try entering some of your future questions into a search engine.

“A healthy rise in blood sugar after eating is much smaller than most people think. The number that’s “too much” depends on what your goals are (weight loss, inflammation, nerve pain, diabetes prevention, etc.).

For most adults, a post‑meal rise of no more than 30–40 mg/dL is considered normal and healthy. Example: If you start at 95, a healthy peak would be 125–135. Anything above that is a sign your body is struggling with the meal.
A rise is too much when:
• Your blood sugar jumps more than 50–60 mg/dL after eating
• Your peak goes over 140 mg/dL at 1 hour
• Your blood sugar is still above 120 mg/dL at 2 hours
• You feel symptoms: bloating, back tightening, nerve buzzing, fatigue, hunger returning quickly.
These numbers don’t mean you’re diabetic — they mean the meal was too carb‑heavy for your current metabolism.

What most people don’t realize is that two meals with the same carbs can affect you very differently. For example:
• Beans → slow carbs = slow increase
• Bread/pasta → fast carbs → big spike → inflammation
• Fruit alone → medium spike
• Protein + veggies → tiny spike

Do you have a CGM? I’ve had Dexcom G7 since 2019 and that’s the only way I found out how certain foods and amount of food affected my blood sugar.

Back in 2018, when I was still just sticking my finger, I noticed dramatic spikes. My doctor said this is not good. He said it was like the fire department being called to a fire every time there was a dramatic spike in blood sugar. He said that over time the body’s pancreas gets tired of all these calls to come put out a “fire”. That alerted me to start journaling what foods and amounts of food were causing these dangerous spikes.

In 2018 Doctor ordered a test of my pancreas = Insulin SerPl-aCnc (normal range 2.0-19.6) and C peptide SerPl-mCnc ( normal range 0.80-3.85).

I was within normal range on both, but my A1C was 10.8! So we ruled out pancreas problem and moved onto the next obvious problem = being overweight.

By end of 2018 I lost 67 pounds in one year, but still my A1C was too high = 9.5! That’s when I decided to try alternative medicine = acupuncture. In one month my high spikes went from 300 down to 200! Unfortunately this progress didn’t last for me, so in 2019 endocrinologist ordered CGM and put me on Ozempic.

My A1C has been between 7.6 and 7.1 since 2020. Fasting labs every 6 months.

Your health and diabetes is most likely not like mine, so take my advice with a grain of salt. My diabetes is complicated by PCOS (diagnosed 1981), high BP (taking meds), high cholesterol (taking fluvastatin), Sleep Apnea (use CPAP), Metabolic Syndrome, Fatty Liver Disease and post menopause severe symptoms (taking HRT).

It’s taken me a long time to put my health and peace ahead of other people’s needs. This journey is about physical AND mental health. Praying you can find the right balance for you. 🙏😃

@louiserivers

I have a stelo, which is a cheap over the counter cgm. I am waiting to hear from my insurance about a dexcom.

I have heard the same thing you heard, and my understanding is one reason someone with T2D and no insulin would have a cgm is to watch out for "dramatic spikes" and then change the pattern, but I don't really know what qualifies as a dramatic spike. What kinds of changes in numbers do you think of as dramatic?

Again, full disclosure: I entered your question “what qualifies as a dramatic spike in blood sugar?” into a search engine and Copilot answered:

“A dramatic spike is any rise in blood sugar that:

• jumps more than 50–60 mg/dL from your starting point
• or reaches over ~140 mg/dL at the 1‑hour mark
• or stays above ~120 mg/dL at 2 hours

Those three things together define a spike that stresses your system.

What counts as a dramatic spike (broken down clearly)

1. Height of the rise. This is the most important part.

• Normal: +20 to +40 mg/dL
• Borderline: +40 to +50 mg/dL
• Dramatic spike: +50 to +60 mg/dL or more
• Very dramatic: +80 to +120 mg/dL

Example: Start at 100 → peak at 165 = dramatic spike
Start at 100 → peak at 190 = very dramatic spike

2. Peak number for most adults:

• Under 140 mg/dL at 1 hour = healthy
• 140–160 mg/dL = borderline
• 160–200 mg/dL = dramatic spike
• 200+ mg/dL = very dramatic spike

3. Steepness of the curve

A spike is dramatic if:

• it shoots up fast
• you see a sharp vertical line on your CGM
• you feel symptoms within 20–40 minutes

Fast spikes cause more inflammation than slow ones.

4. How long it stays high

A spike is dramatic if:

• you’re still above 120 mg/dL at 2 hours
• or you don’t return to baseline for 3–4 hours

This means your body struggled to clear the glucose.

@louiserivers that’s helpful, but I also think that anything with blood sugar is going to be dramatically different with diabetes. I might ask the question again with T2D in the question.

@anonymom3
You ask good questions!
Unfortunately equally good answers are sometimes hard to come by, like on this one. Until the CGM nobody really did much study on how normal, that is non-diabetic, that is normal A1C, people digest their carbs. So there was no textbook. The first Dexcom was sold around 2006.
Now there is some data on normals and some on diabetics, but there are still many variables and the textbook is still pretty thin, afaik.

What if a normal person pigs out at a party, what then? I mean, it's probably good not to make a habit of that but people are built to be able to enjoy a big meal now and then, and to be able to go on small meals now and then, with no real damage. But just how fat they are, and how fit they are, is going to affect BG readings.

So to just get a big picture view the relevant metric is probably something like total area under the curve.

If you eat the whole birthday cake, normal or diabetic you're going to have a spike. If you're normal the body restores order quickly enough, if you're diabetic maybe not so much. OTOH if you're a diabetic taking insulin you can adjust your dosage. If you're on metformin or Ozympic or whatever, you're going to see a different curve.

My endo told me, if I get more than one or two readings above 200, call him, but those would be pre-meal readings, let's say at least four hours since finishing the last meal.

They say that your BG should return to normal about two hours after a meal, but I've noticed, just on finger-sticks, that my recovery often takes longer. This is probably a diabetic factor. Given 4-5 hours my finger-stick readings continue to be good, my A1C stays just below the pre-diabetic line of 5.7, so things are working for me. If I pig out on a meal it may be reflected for as long as 24 hours with readings 10-20 points (sometimes more) above my normal.

So it's basically the area beneath the curve, and that's pretty much what your meter must be doing to estimate A1C.

@anonymom3
Yes, definitely do your research and Google your question with T2D in your question.

I’ve been diabetic since 2005. You said you were recently diagnosed with diabetes and an A1C of 13. We are at different times in our diabetic journey. If I could go back to 2005, I would do EVERYTHING in my power to reverse being diabetic.

I would encourage and challenge you to get back to pre diabetic numbers. This means don’t just try to stay within the normal diabetic ranges of BG. Strive to not be diabetic.

Google all the different possible health problems which come with diabetes over your life time. Then also look at your family health history. Do you have a family history of diabetes, high BP, high cholesterol, heart attack, stroke, cataracts and glaucoma?

That’s my family history. Even today I’m still striving to just get my diabetes under control with the deck stacked against me. Don’t let that be you. Learn from those of us who’ve are dealing with all the complications that come from years of uncontrolled diabetes.

Praying you get the information and medical help you need so you can live a long and healthy life free of this terrible disease. 🙏

I try to keep the rise in my blood sugars below 225; if it rises above this level, I take notes on the things I've ate to take them off my diet/food list. I follow my diet closely & have low carb/low sugar diet. There are meal delivery services that specialize in this area. I'm new to medicare and they offer food delivery for diabetics for a 17 week period (5 days -- lunch and dinner). It is a pretty good way to kick-off your retirement. I've lost 25 pounds over 4 months & my A1C is 6.9 for the past 90 days. I am also on Mounjaro as well.