A Nutritionist’s Take on Blood Sugar Monitoring

By Sinead Berry, Registered Nutritionist (MSc, mBANT, rCNHC)

By Sinead Berry, Registered Nutritionist (MSc, mBANT, rCNHC)

Health and wellness fads and trends come and go like the seasons. And you may have noticed that calorie-counting has crashed while blood sugar management is on the rise — whether it’s monitoring through the latest devices and apps, or diet and lifestyle hacks that promise to balance your blood sugar and optimise your health. But the concept of blood sugar monitoring and management isn’t new. For those people living with diabetes, daily blood sugar checking is a necessity. An essential part of this monitoring is the use of a continuous glucose monitor (CGM), where a sensor detects how much glucose is in the fluid under the skin, in real-time, 24-hours a day; the results are transmitted to the wearable device or smartphone. 

As with many things in the wellness world, what was once used by a small part of the population, has now become the latest craze for many people to monitor their responses to specific foods. Of course, with access to this information comes the risk that people without diabetes become fixated on the idea that the route to a healthier, happier life is to only eat foods that keep blood sugar levels stable. But is this simply another passing wellness fad or something that we could all benefit from understanding? 

Symptoms of imbalanced blood sugar are wide-ranging — from excess belly fat, anxiety (1) and fatigue to headaches and skin issues such as acne (2) — and if afternoon energy slumps are leaving you tired, down in the dumps and craving sugar, you may well have a problem balancing your blood sugar. However, is it only food that has the ability to influence our blood glucose levels or is there more to it than that? Here’s the lowdown on blood sugar — what it is, how it may impact your health day-to-day and whether it’s crucial for long-term health, plus the key takeaways from the latest science.

What even is blood sugar? 

Blood sugar is another term for the amount of glucose circulating in our blood and is produced when your food — predominantly carbohydrates — is broken down during digestion.

When we eat or drink, the carbohydrates in what we’ve consumed are digested and the body’s main energy source, glucose, is produced. When blood sugar rises, our pancreas releases the hormone insulin, which regulates blood sugar by signalling to muscle cells to absorb it for energy or storage; any excess is stored as fat. Our blood sugar needs to remain within a tightly controlled range because only so much can be processed by our cells at any one time. This is particularly vital for people with diabetes as uncontrolled, it may lead to complications including kidney damage, vision loss and increased risk of heart disease (3). 

When a healthy person eats a balanced meal including protein, healthy fats, complex carbs and fibre, they experience a temporary moderate rise in blood glucose, before insulin gets to work and quickly returns levels to normal. This helps maintain a steady flow of energy throughout the day. When we eat food that’s high in simple carbs (that release sugar quickly — think white bread, pastries, white pasta, fizzy drinks), our blood sugar levels spike rapidly and too much insulin is released, making blood sugar levels plummet, potentially even lower than before you started eating. The higher the blood sugar spike, the greater the crash, and your body doesn’t have enough energy to function effectively. In the short-term, you’re left feeling tired, irritable and craving carb-heavy foods or stimulants, such as a mid-afternoon coffee to get you through the afternoon — these will bring blood sugar levels back up, but then the cycle simply continues on repeat.

How do blood sugar levels impact our long-term health?

Well-regulated blood sugar gives the body a sustained supply of fuel resulting in stable energy levels, supporting brain and organ function, muscle activity and overall health. This may mean a positive impact on everything from mood and focus, to fewer cravings and better sleep. It’s important to keep in mind that glucose levels will naturally fluctuate throughout the day, it’s only when these peaks and troughs are exaggerated or glucose levels are chronically high that problems may occur. 

Over the long term, excess glucose in the blood has the potential to cause damage around the body, affecting cell function and reducing insulin sensitivity (4). This may cause symptoms such as low energy, irregular periods, fertility problems, acne, weight gain and poor sleep. If left unchecked, this can lead to prediabetes, type 2 diabetes or heart disease (5). Research has also found that extreme peaks and troughs of blood sugar levels (also known as the ‘blood sugar rollercoaster’) may increase oxidative stress (when there’s an imbalance between the production of damaging free radicals and the body’s ability to detoxify or neutralise them), inflammation and the risk of heart disease to a greater degree than a constantly high glucose level (6).

Are we oversimplifying a complex condition by just focusing on food?

While there’s no doubt that our food choices have the potential to dramatically impact our blood glucose regulation, it’s also crucial to understand that blood sugar balance is not only affected by what you eat, there are other lifestyle factors at play too. Stress may have a big impact on blood sugar and insulin levels. When you’re stressed, your body releases the stress hormone cortisol, which triggers the release of glucose and prevents insulin from being secreted (7). This is bad news for blood sugar balance as glucose levels in the blood remain persistently high and cells can’t get the energy they need. It’s not possible, of course, to eliminate all of life’s stressors, but there are ways to better control both blood sugar and stress levels. Research has shown that moderate exercise on alternate days for 12 weeks (8) and mindfulness-based stress reduction techniques may lead to better blood sugar management, as well as lower levels of anxiety (9).

Sleep and blood sugar also have a two-way relationship — how well you sleep may be impacting your blood sugar levels and what your glucose levels are doing during the night may be impacting how well you’re sleeping. A recent large study examining sleep patterns found that people who didn’t sleep well or went to bed later had larger blood sugar spikes after breakfast (10). This is likely due to increased morning cortisol levels resulting from disrupted sleep and reduced insulin sensitivity (11). Going to bed earlier led to better blood sugar control. 

In women, the fluctuating hormones of the menstrual cycle may also disrupt blood sugar balance (12). During the first half of your cycle, oestrogen rises, peaking just before ovulation; and it’s during this time that your body is most sensitive to insulin. After ovulation, oestrogen drops and progesterone rises; this is when your body becomes more insulin-resistant and blood sugar spikes. You may notice this with sugar cravings and low mood the week before your period. More cortisol is also released during the second half of your cycle, which as we know, reduces insulin sensitivity. The fall in oestrogen may also cause a drop in serotonin (the ‘happy hormone’), leading to further cravings for sugary foods. Tuning into your cycle and being mindful of blood sugar balance during these hormone fluctuations may help women to better manage premenstrual symptoms. For example, making sure to combine complex carbs with good-quality protein, fibre and healthy fats in every meal, particularly during the second half of your cycle, may combat cravings and fatigue.

But is this latest health metric actually a ‘magic bullet’ for short- and long-term health? 

Although the health benefits of glucose monitoring for those with diabetes is evident, there’s currently no robust evidence showing that, for healthy people, monitoring your blood glucose using a CGM leads to improved health. Having this additional information about how our bodies are functioning is undeniably interesting and may give us a sense of control over our health, but with this knowledge also comes risk. Becoming hyper-fixated on flattening blood sugar curves may lead to people cutting out vital food groups from their diet, increasing the risk of unnecessarily limiting fibre, vitamins, minerals and antioxidants, which won’t do your health any favours in the long term. 

It’s important to understand that while balanced blood sugar is critical for so many aspects of short- and long-term health, and so many factors have the potential to disrupt this fine balance, the occasional glucose spike here and there is not going to be solely responsible for the downfall of your long-term health. Instead, being mindful that eating balanced, nutritious meals packed with a variety of wholefoods as part of a healthy lifestyle will benefit your health more in the long run than obsessing over the impact on your blood sugar of individual foods. After all, food is more than just numbers, it’s nourishment, pleasure and social connection.

Actionable tips to support healthy blood sugar levels 

There are a number of simple food and lifestyle habits that healthy people can use to maintain steady blood sugar levels, without the need for constant monitoring.

1. Swap the simple carbs for complex ones (such as wholegrains and beans). Complex carbs are higher in fibre which takes longer to digest and slows down the absorption of sugar. This means that energy is released more slowly, keeping levels steady throughout the day.

2. Combine your carbs with good-quality protein, fibre and healthy fats (try this Tofu & Chickpea Korma Curry or Speedy Weeknight Stir-Fry, for example). This combination takes longer to digest and ensures a steady release of energy, avoiding the highs and lows of the blood sugar rollercoaster. Eating a protein-rich breakfast (such as this Creamy Peas on Toast) is particularly important as it makes it easier to maintain stable glucose levels throughout the day. 

3. Try a shot of apple cider vinegar before meals: The benefits of apple cider vinegar are widely documented, however current evidence suggests a modest beneficial effect of apple cider vinegar on reducing blood glucose levels when taken with meals (13). Mix 1–2 tablespoons into a glass of water. 

4. Eat regularly. Not eating for extended periods throughout the day will cause blood sugar levels to drop, leaving you feeling hungry, low in energy and making it more likely that you will reach for a sugary snack. Research has found an association between meal regularity and lower glucose responses, where eating every 3–4 hours may help to maintain constant blood sugar levels (14).

5. Consider the order in which you eat your food. Although research is limited, studies have shown that something as simple as eating the vegetables and protein before carbs during a meal, may reduce the rise in blood sugar and insulin levels (15). 

6. Get moving. One study found that just 10 minutes of walking, particularly when straight after a meal, was linked to a 22% reduction in blood sugar levels (16). Moving your body requires energy; during exercise the muscles use glucose from the blood for energy. This helps to lower blood sugar levels and increase insulin sensitivity, meaning that your cells can more effectively use the available sugar in your bloodstream (which is a good thing!). 

7. Sleep more, try to reduce stress. Research has shown that stress-busting practices such as yoga and mindfulness may help to regulate blood sugar levels (17).

An example menu for balanced blood sugar throughout the day:

15-Minute Tomato & Harissa Chickpeas
15 mins

15-Minute Tomato & Harissa Chickpeas

Super quick and versatile with minimum prep. Garlic and ginger are the only things you need to chop! These creamy, flavourful chickpeas are great on toast or with cooked grains. Feel free to play around with toppings. We’ve suggested basil, tahini & sesame seeds, but lots of things will work.

View Recipe
Protein-Packed Quinoa Caesar Bowl
25 mins

Protein-Packed Quinoa Caesar Bowl

I have a feeling this creamy Caesar bowl is going to be our most popular recipe of 2023; I can’t recommend it highly enough. Not only is it absolutely delicious and ready in under 30 minutes, it’s also loaded with nearly 35g of plant-based protein in every serving, thanks to the chickpeas, tofu, edamame beans and quinoa. Combine this with fibre and healthy fats, and you have the perfect dish to keep you feeling fuller for longer.

View Recipe
Tofu & Kimchi Fried Rice
25 mins

Tofu & Kimchi Fried Rice

This dish has got everything going for it. Tangy, punchy flavours from the kimchi & tamari, plenty of crunchy veggies, plenty of protein to fill you up. As well as being a great source of protein, the silken tofu crumbles up to give you an egg-fried rice type texture.

View Recipe

Sinéad Berry, Registered Nutritionist (MSc, mBANT, rCNHC)




1. Monique Aucoin, Sukriti Bhardwaj, "Generalized Anxiety Disorder and Hypoglycemia Symptoms Improved with Diet Modification", Case Reports in Psychiatry, 2016; vol. 2016, Article ID 7165425.

2. Emiroğlu N, Cengiz FP, Kemeriz F. Insulin resistance in severe acne vulgaris. Postepy Dermatol Alergol. 2015 Aug;32(4):281-5.

3. Rask-Madsen C, King GL. Vascular complications of diabetes: mechanisms of injury and protective factors. Cell Metab. 2013 Jan 8;17(1):20-33.

4. Kawahito S, Kitahata H, Oshita S. Problems associated with glucose toxicity: role of hyperglycemia-induced oxidative stress. World J Gastroenterol. 2009 Sep 7;15(33):4137-42.

5. Blaak EE, Antoine JM, Benton D, Björck I, Bozzetto L, Brouns F, Diamant M, Dye L, Hulshof T, Holst JJ, Lamport DJ, Laville M, Lawton CL, Meheust A, Nilson A, Normand S, Rivellese AA, Theis S, Torekov SS, Vinoy S. Impact of postprandial glycaemia on health and prevention of disease. Obes Rev. 2012 Oct;13(10):923-84.

6. Antonio Ceriello, Katherine Esposito, Ludovica Piconi, Michael A. Ihnat, Jessica E. Thorpe, Roberto Testa, Massimo Boemi, Dario Giugliano; Oscillating Glucose Is More Deleterious to Endothelial Function and Oxidative Stress Than Mean Glucose in Normal and Type 2 Diabetic Patients. Diabetes 1 May 2008; 57(5):1349–1354

7. Yaribeygi H, Maleki M, Butler AE, Jamialahmadi T, Sahebkar A. Molecular mechanisms linking stress and insulin resistance. EXCLI J. 2022 Jan 24;21:317-334.

8. Trimurthula SR, Perakam S, Kondapalli A. The Effect of Jacobson’s Progressive Muscle Relaxation Technique along with Structured Exercise Program on HbA1c in Type II Diabetes Mellitus Patients. International Journal of Health Sciences and Research. 2020; 10(7):28-34. 

9. Armani Kian A, Vahdani B, Noorbala AA, Nejatisafa A, Arbabi M, Zenoozian S, Nakhjavani M. The Impact of Mindfulness-Based Stress Reduction on Emotional Wellbeing and Glycemic Control of Patients with Type 2 Diabetes Mellitus. J Diabetes Res. 2018 Jun 10;2018:1986820.

10. Tsereteli, N., Vallat, R., Fernandez-Tajes, J. et al. Impact of insufficient sleep on dysregulated blood glucose control under standardised meal conditions. Diabetologia. 2022; 65, 356–365.

11. Stamatakis KA, Punjabi NM. Effects of sleep fragmentation on glucose metabolism in normal subjects. Chest. 2010 Jan;137(1):95-101.

12. Brown SA, Jiang B, McElwee-Malloy M, Wakeman C, Breton MD. Fluctuations of Hyperglycemia and Insulin Sensitivity Are Linked to Menstrual Cycle Phases in Women With T1D. J Diabetes Sci Technol. 2015 Oct 14;9(6):1192-9.

13. Johnston CS, Buller AJ. Vinegar and peanut products as complementary foods to reduce postprandial glycemia. J Am Diet Assoc. 2005 Dec;105(12):1939-42.

14. Alhussain MH, Macdonald IA, Taylor MA. Irregular meal-pattern effects on energy expenditure, metabolism, and appetite regulation: A randomized controlled trial in healthy normal-weight women. Am J Clin Nutr. 2016;104(1):21–32. 

15. Ferguson BK, Wilson PB. Ordered Eating and Its Effects on Various Postprandial Health Markers: A Systematic Review. J Am Nutr Assoc. 2022 Dec 27:1-12.

16. Reynolds, A.N., Mann, J.I., Williams, S. et al. Advice to walk after meals is more effective for lowering postprandial glycaemia in type 2 diabetes mellitus than advice that does not specify timing: a randomised crossover study. Diabetologia. 2016; 59, 2572–2578.

17. Kim SD. Effects of yogic exercises on life stress and blood glucose levels in nursing students. J Phys Ther Sci. 2014 Dec;26(12):2003-6.

Delicious Ways to Feel Better

Discover simple tools for a healthier life

Become a Deliciously Ella member today