Written by Dr Edward Leatham, Consultant Cardiologist

This blog explores how individuals can conduct their own experiments to maintain a steady blood glucose and avoid potentially unhealthy glucose spikes above 7.8 mmol/L (140 mg/dL).

A separate blog addresses the more difficult question of what evidence is out there that glucose dysregulation in non diabetic people matters.

Empowering Personal Health Through N-of-1 Trials

Modern medicine has advanced through clinical trials where a large number of patients with a given condition are randomly allocated to receive either a trial drug, or placebo. By blinding both the patient and their medical team (double blind), no bias from other treatments or beliefs can be introduced, since neither the patient or their medical team knows who is receiving active drug. It is argued that there is sufficient similarity between individual patients in the study group for any measured benefits of the active treatment to be applicable to any other patients with a similar medical condition.  The obvious limitation of this approach is that since each human is genetically unique, they may respond differently to any one  intervention.  It is also important to remember that negative trials are less published than positive trials, so what readers pick up on internet searches can often be only part of the story.  Nowhere is this more evident than in the realm of glucose management, where an individual’s response to a standard food intake can vary enormously – not only because of genetic factors, but also due to variations in gut microbiome which greatly affects release of glucose from digested food. It means that when it comes to making recommendations about ways to improve metabolic health, there are plenty of unproven strategies out there, that might help.

An obvious way to get around individual variability in response to dietary, lifestyle and medical therapies, is for each patient shown to have apparently ‘unhealthy’  glucose excursions (‘spikes’), to conduct their own experiment, using their pretreatment self as the control.

This form of personalised research is perfectly valid and certainly gets around the concern that there is no ‘one size fits all’ approach to interventions that can improve metabolic health.  The advent of the continuous glucose monitor has made the  N-of-1 trial a research tool [2] equally feasible for both academic groups conducting a formal research trial and for patients, motivated to find out what really works in their individual case. By analysing an individual’s glucose results from 2 weeks of CGM before and after the intervention, it is relatively easy to judge which intervention has had a useful impact. With over 1000 glucose points measured during the lifetime of one CGM device worn over 10-14 days, there are sufficient data available for known metrics of importance, such as ‘time in range’, and glucose variability (GV) to be compared before and after a dietary or lifestyle intervention, see an example here.

Here are some strategies widely reported to optimise blood glucose control. Some are proven in large trials, while others  remain unproven, possibly due to the high cost of rigorously designed and conducted clinical trials but also because negative trials are less often reported. With CGMs increasingly available to all, it is possible for any patient to test whether the interventions 1-13 set out below have a significant ‘glucose flattening’ effect.

1. Embrace Regular Exercise and Daily Movement

Exercise isn’t just about weight loss; it’s a critical factor in increasing insulin sensitivity, which enables more effective glucose absorption in your cells. Regular physical activity helps muscles use blood sugar for energy and muscle contraction, crucial for keeping glucose levels steady.

For those managing blood sugar issues, tracking glucose levels before and after exercise can provide valuable insights into how your body reacts to different types of physical activities. If dedicating long periods to exercise is challenging, consider shorter, more frequent sessions. Aim for activities spread throughout the week to accumulate at least 150 minutes of exercise per week.

Introducing “exercise snacks” can also help counteract the effects of prolonged sitting. These are short bursts of activity every 30 minutes—such as walking, squats, or leg raises—that break up sedentary time effectively. For desk-bound individuals, alternating between sitting and standing using a stand-up desk can keep the body dynamically engaged throughout the day.

Additional forms of beneficial exercise include:

• Weightlifting
• Brisk walking
• Running
• Cycling
• Dancing
• Hiking
• Swimming
• Jumping jacks
• Half squats

Any form of movement, regardless of intensity, is better than maintaining a sedentary lifestyle and can significantly contribute to blood sugar management.

2. Manage Your Carbohydrate Intake

Carbohydrates directly influence blood sugar levels. They are broken down into sugars, primarily glucose, which insulin then helps to store and use for energy. Problems arise when excessive carbs are consumed or if there’s a dysfunction in insulin activity, leading to increased blood glucose levels.

Carb counting is a practical approach that can help you plan your meals better and enhance blood sugar management. Adopting a low-carb diet is known to help reduce blood sugar levels and prevent spikes. When consuming carbohydrates, it’s healthier to choose those with a lower glycaemic index, such as whole grains and unprocessed foods, to gain maximum nutritional benefit while minimising blood sugar increases.

The timing of carbohydrate intake also makes a big difference, generally the earlier in the day being better for most people. A particularly effective strategy is to adopt ‘no carbs after 2 pm’ – a widely accepted technique to achieve weight loss, its main flaw being one’s ability to sustain such a strict routine.

3. Increase Your Fibre Intake

High fibre foods such as avocado, broccoli, onions and peppers, do not contain sufficient carbohydrate to cause a rapid rise in blood glucose, so are a good choice to fill up on and achieve satiation of appetite. High fibre goods also moderate how other high carb foods, including starch and ‘ beige foods’, are digested and glucose content absorbed, promoting a gradual increase in blood sugar rather than spikes. Soluble fibre, in particular, has been shown to significantly help manage blood sugar levels. Foods high in fibre include:

• Vegetables
• Fruits
• Legumes
• Whole grains

Men should aim for about 35 grams of fibre per day, and women should aim for about 25 grams, or roughly 14 grams per 1,000 calories consumed.

4. Strategic Weight Management

Maintaining a healthy weight helps optimal blood sugar control and can reduce the risk of developing diabetes. Even a modest weight loss of 5% of total body weight can improve blood sugar regulation and decrease the need for medications. For instance, a person weighing 91 kilograms who loses about 4.5 to 6 kilograms may see marked improvements in blood sugar levels.

There are plenty of reports that dietary and lifestyle changes that lead to glucose flattening are associated with weight loss too, creating a potential extra  benefit.

5. Implement Portion Control

For those above their ideal weight, particularly if extra weight is carried around the midsection, managing portion sizes can be an effective way to control calorie intake and lose weight. Other well rated methods including eating less frequently, avoidance of  eating carbs before sleep, increasing water intake, using smaller plates, checking food labels for recommended serving sizes, keeping a food journal, and using food-tracking apps.

6. Stay Hydrated

Drinking sufficient water is essential for overall health and helps manage hunger, which can keep blood sugar levels stable. Water assists the kidneys in flushing out excess sugar through urine and helps prevent dehydration.

7. Combine Proteins and Healthy Fats with Carbohydrates

Adding proteins or healthy fats to your meals can reduce the rate at which carbohydrates are absorbed and minimise blood sugar spikes post-meal. One patient recently told me that her glucose spike after morning tea taken with milk (lactose) was resolved by replacing low fat milk with full fat milk. This can be especially helpful in maintaining a smoother glucose curve throughout the day. It makes sense to adopt the food group ratios recommended in the healthy eating plate published by Harvard university [8].

8. Manage Stress

Stress can cause blood sugar levels to rise due to the secretion of stress hormones like glucagon and cortisol. Employing stress management techniques such as exercise, meditation, deep breathing, and engaging in hobbies can help lower stress and its impact on blood sugar.

9. Monitor Blood Glucose Levels

Using a CGM to track how different foods and activities affect your blood sugar allows for real-time adjustments in your diet and lifestyle. This can be helpful in spotting patterns such as poor glucose regulation on stressful days that might lead to abstinence from carbohydrates on high stress days, avoidance of certain foods linked to major spikes or to experiment with other glucose lowering hacks reported for example in the latter pages of ‘Glucose revolution’ [9].

10. Ensure Quality Sleep

Sleep has a profound impact on blood sugar levels and insulin sensitivity. Poor sleep habits can increase the risk of developing type 2 diabetes. Adults should aim for 7 to 8 hours of quality sleep per night, establishing a regular sleep routine and creating a restful sleeping environment.

There are reports that dietary and lifestyle changes that lead to glucose flattening are associated with improved quality sleep, creating ‘chicken or  egg, which came first’ type of question.  Whatever the answer,  the benefits of better sleep on overall health are unarguable.

11. Experiment with Non-Medicinal Supplements

While it might be argued that more research is needed to promote wide-scale use , certain foods and supplements like apple cider vinegar, cinnamon, berberine, and fenugreek seeds have been shown to improve blood glucose management. Bearing in mind not everyone will respond the same to these non medicinal compounds, some may be beneficial.
Exploring supplements as part of your personal N=1 trial may therefore be worthwhile, to see what works best for you.

12. Include Probiotic-Rich Foods

Probiotics can improve gut health and may help manage blood sugar levels. Including probiotic-rich foods like yogurt, kefir, and fermented vegetables in your diet can offer benefits for blood sugar regulation.

13. Try out prolonged fasting

There are many variations of prolonged fasting, however they all are based on the same principle of ‘resting’ the pancreatic release of insulin and  desensitising tissues that bind to insulin, lowering the chance of developing ‘insulin resistance’.  By resulting in less intake, prolonged fasts can also help with weight management.  This may be particular effective when applied overnight – achieved by taking an early and lighter evening meal, combined with a fast until breakfast time when it can be taken a little later than usual.

Conclusion

Effective management of your blood glucose levels is not just about preventing or managing diabetes; it’s about enhancing your overall health. Through personalised N=1 trials, using CGMs, you can discover the diet and lifestyle adjustments that work best for you, leading to sustained health improvements. If you find that your glucose levels remain challenging to manage, it is advisable to seek medical input, as medications and other medical interventions might be necessary.

The Surrey Cardiovascular clinic was established in 2006 as a specialist cardiovascular centre of excellence. Alongside specialist CT imaging and AI techniques for rapid 1 stop diagnosis of coronary heart disease, we specialise in preventative medicine. Our team of cardiologists, diabetologists, specialist nurse practitioners, dieticians and nutritional therapists presents a wholly multi disciplinary approach to maintaining good health and preventing symptomatic heart disease.  Due to the increasing importance of data flow and analysis, we operate a separate data processing company (MedicalSpace Ltd) that provides data processing for of all our clinical data. We have data processing and expert reporting packages for patients using Abbot Freestyle Libre CGMs who wish to get more information from their CGM devices. 

Further reading

1. Gene mutation evolved to cope with modern high-sugar diets
2. The n-of-1 clinical trial: the ultimate strategy for individualizing medicine?
3. https://pan.olsztyn.pl/2023/04/human-genes-cant-keep-up-with-adaptation-to-modern-diet/
4. https://drindra.co.uk/its-all-a-balancing-act-the-art-of-achieving-a-steady-blood-glucose/
5. https://www.aware.app/magazine/glucose-strategies-how-to-flatten-your-glucose-curve-with-10-tips
6. Diabetes: is it time to flatten the curve? 2021

7. 14 Easy Ways to Lower Blood Sugar Levels Naturally

8. The Harvard Eating plate 
9. Glucose revolution