#474: Glucose Peaks & Variability – Is Lower Better?

In Podcasts by Danny Lennon4 Comments


Often claims are made recommending that people should aim to keep peaks in blood glucose low in terms of both magnitude and frequency.

And while many claims about blood glucose “spikes” are incorrect or purposefully exaggerated to grab attention, there are some reasonable and interesting hypotheses put forward in relation to blood glucose variability and excursions.

For example, interesting questions have been raised in relation to the impact of blood glucose excursions in seemingly normoglycemic and/or healthy people.

In this episode, we look at three specific elements of this: average blood glucose, glucose variability, and glucose peaks. All in the context of people without prediabetes or type diabetes, who have typical blood glucose measures in the ‘normal’ range.

Specifically, we look at three hypothesized recommendations made elsewhere:

  1. “The lower you average blood glucose (HbA1C) is better, even if already in normal range”
  2. “The more you can minimize glucose variability, the better.”
  3. “Minimizing the number of glucose “peaks” is important, even if they don’t meet the threshold for hyperglycemia”

Can normoglycemic people benefit from further reducing these measures? Let’s take a look…

Co-hosts for this Episode

Dr. Alan Flanagan has a PhD in nutrition from the University of Surrey, where his doctoral research focused on circadian rhythms, feeding, and chrononutrition.

This work was based on human intervention trials. He also has a Masters in Nutritional Medicine from the same institution.

Dr. Flanagan is a regular co-host of Sigma Nutrition Radio. He also produces written content for Sigma Nutrition, as part of his role as Research Communication Officer.

Danny Lennon has a master’s degree (MSc.) in Nutritional Sciences from University College Cork, and he is the founder of Sigma Nutrition.

Danny is currently a member of the Advisory Board of the Sports Nutrition Association, the global regulatory body responsible for the standardisation of best practice in the sports nutrition profession.


  • Definitions & Cut-Offs
  • Is Lower Average Blood Glucose Better?
  • Glucose Variability
  • Glucose Peaks
  • Some Pragmatic Considerations

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  1. Hi Danny and Alan

    Peaks in blood glucose has been debated in my team. Some claim specifically that eating processed, high sugar foods causes a rapid rise and then a rapid fall in blood glucose and low blood glucose levels. Following this, the rapid fall in blood glucose/low blood glucose leads to increased hunger and cravings for more sugary food.

    Do you of any evidence for this?

    I’m a new subscriber and have found the additional content really great, thanks the excellent job you do promoting evidence based advice.

    1. Author

      Hi Judith,

      There are many ways that eating a diet high in highly processed foods and added sugar could lead to greater hunger, so I’m not sure we should put that just to postprandial response.

      Also the context likely matters. For example, are you talking about true reactive hypoglycemia? Is this in a patient with T1DM or a normoglycemic person?

      If there are specific studies being cited that would be useful, so that we can narrow down to a concise answer.

  2. Hi Danny

    I found your podcast really interesting and helped to define for me the cut offs for various blood glucose levels. I also noted you say that – “Some people make an error when they equate a blood glucose “spike” with an unhealthy response. Rather, someone with completely healthy glucose tolerance can “spike” their BG by consuming a large CHO load. But if they can effectively handle that, i.e., have BG return to normal in an appropriate amount of time, then the spike isn’t a problem. That’s just a normal response to the CHO load. So the idea that one should “never spike their blood glucose” doesn’t make any sense.”

    There seems to be a common belief that a rapid rise and then fall in blood glucose, for example after eating a food high in sugar will cause a range of impacts including increased hunger, cravings for more sugary foods and possibly low energy levels. This is in people who do not have diabetes.

    I have been looking for studies to back this up but not found anything specific (although I’m relying on Google) but there is lots of general info on the web quoting this effect, Jessie Inchauspé, aka @GlucoseGoddess, seems to be a more recent source of this.

    Is there any evidence for these impacts in relation to a rapid spikes in blood glucose in people without diabetes?

    1. Author

      Hi Judith,

      I think my answer would be similar to the one I posted above to your previous comment.

      In the context of people without diabetes, there are lots of talks about implications of “spikes” in glucose. Some of these claims mention elevations that are not even that high, and hence I think it problamatizing something that isn’t an issue. Of the few posts people have sent me from @GlucoseGoddess, I don’t see her as a reputable source of information on this topic.

      Where is there is perhaps some debate, is where we lack evidence… i.e. in cases where the excursions are incredibly high, then is this a risk or not? But we need to be clear on the peak glucose level achieved and then it’s response in the time after that.

      Right now I see people taking cut-off points for 2-hr OGTTs, and using those figures when interpreting a spike. But this is incorrect. Those cut-offs are standardized measures specifically for a 2 hour response.

      When it comes to your question of hunger specifically, clearly eating highly-refined foods with added sugar can leave people hungrier sooner after eating compared to another meal. But to extrapolate this to mean its solely down to glucose is an error. To take an extreme example purely for the point of illustration, if someone were to consume equal calories from potato and olive oil, which one would lead them to being hungry again sooner? Despite the BG elevation from potato, this is a food that has been shown to have a huge satiety effect. So there is way more to hunger than BG going up and down.

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