5 reasons for blood glucose fluctuations

One of the most common benefits of following a low carb lifestyle is greater blood glucose [sugar] control. However, despite lowering their carbohydrate intake, some people may experience blood glucose fluctuations.

While it can seem frustrating, it’s important to understand that there are lots of different factors which can influence the blood glucose level.

Here are a few examples, some of which may surprise you:

Dawn Phenomenon

The dawn phenomenon occurs in people with and without diabetes. It refers to the rise in blood glucose in the early morning due to the release of certain hormones, including cortisol. For people with type 2 diabetes or high insulin resistance, insulin may have less of an effect in counteracting this blood glucose rise, so they may experience a higher morning reading [1].


Stress hormones are also released by our body when we’re sick to help combat infection [2]. So, during times of illness we may experience a higher blood glucose level.


Certain medications such as steroids and some types of diuretics can lead to fluctuations in blood glucose level [3]. If you feel that medication may be the reason for high blood glucose it is suggested that you discuss this with your doctor.


Different stages of the menstrual cycle can have an impact on blood glucose levels. For example, some women may find that their blood glucose may rise before or during their period due to changes in levels of oestrogen and progesterone which can lead to a temporary rise in insulin resistance [4].

Inaccurate readings

It may seem obvious, but sometimes blood glucose reading fluctuations may be down to inaccurate meter readings. This could be due to technique, such as glucose from food on the skin. Glucose monitors can be very sensitive so, if you’re unsure, consider washing your hands and re-checking [5].


You can learn more about other possible reasons for blood glucose fluctuations when you join the Low Carb Program. 




[1]   Porcellati, F., Lucidi, P., Bolli, G.B. and Fanelli, C.G., 2013. Thirty years of research on the dawn phenomenon: lessons to optimize blood glucose control in diabetes. Diabetes Care36(12), pp.3860-3862.

[2]       Rayfield, E.J., Ault, M.J., Keusch, G.T., Brothers, M.J., Nechemias, C. and Smith, H., 1982. Infection and diabetes: the case for glucose control. The American journal of medicine72(3), pp.439-450.

[3]       Buscemi, S., Nicolucci, A., Lucisano, G., Galvano, F., Grosso, G., Massenti, F.M., Amodio, E., Bonura, A., Sprini, D. and Rini, G.B., 2013. Impact of chronic diuretic treatment on glucose homeostasis. Diabetology & metabolic syndrome5(1), p.80

[4]      Yeung, E.H., Zhang, C., Mumford, S.L., Ye, A., Trevisan, M., Chen, L., Browne, R.W., Wactawski-Wende, J. and Schisterman, E.F., 2010. Longitudinal study of insulin resistance and sex hormones over the menstrual cycle: the BioCycle Study. The Journal of Clinical Endocrinology & Metabolism95(12), pp.5435-5442.

[5]      Hirose, T., Mita, T., Fujitani, Y., Kawamori, R. and Watada, H., 2011. Glucose monitoring after fruit peeling: pseudohyperglycemia when neglecting hand washing before fingertip blood sampling: wash your hands with tap water before you check blood glucose level. Diabetes Care34(3), pp.596-597.