Balancing your blood sugar: what actually makes a difference

A bowl of white rice eaten on its own and a plate combining rice, vegetables, lentils and fish both contain carbohydrates. Yet they can produce very different blood glucose responses.

The amount of carbohydrate matters, of course. But its structure, fibre content, the composition of the meal and even what you've been doing in the hours beforehand all influence how your body processes it.

This is why healthy blood sugar regulation matters: understanding what helps your body absorb, use and store glucose efficiently, throughout the day and over the years.

Why is this important?

Because our ability to regulate blood glucose and respond effectively to insulin plays a central role in metabolic health.

Is a rise in blood glucose after a meal a problem?

After a meal containing carbohydrates, digestion releases glucose into the bloodstream. This rise is entirely normal and physiological: glucose becomes available to fuel our cells, particularly those in the brain and muscles, or to replenish our energy stores.

In response, the pancreas releases insulin, a hormone that helps the body use and store glucose. Between meals, the liver helps maintain stable blood glucose levels, partly through the action of glucagon.

What matters is how effectively the body regulates blood glucose after each meal.

When cells become less sensitive to insulin, the pancreas may need to produce more of it to keep blood glucose within the normal range. Over time, this disruption can contribute to the development of type 2 diabetes and increase cardiovascular risk.

Glycaemic index and glycaemic load: two different measures

• The glycaemic index (GI) indicates how much a carbohydrate-containing food raises blood glucose compared with a reference food, under standardised conditions.

• The glycaemic load (GL) also takes into account the amount of carbohydrate consumed in a portion.

For example, watermelon has a relatively high glycaemic index but a low glycaemic load for a typical serving, because it contains a lot of water and relatively little carbohydrate.

These measures can be useful, but glycaemic responses vary considerably between individuals.

A 2025 study published in Nature Medicine used continuous glucose monitoring to measure responses to different carbohydrate foods. On average, rice produced the highest glucose response, but there were substantial differences between participants, partly related to insulin sensitivity. Consuming fibre, protein or fat before the carbohydrate reduced the glucose response in most participants, although the effect was smaller in those with insulin resistance.

Cooking methods, meal composition, physical activity, sleep and insulin sensitivity can all influence this response.

Ultimately, rather than memorising the glycaemic index of every food, it is more useful to understand the everyday factors that can improve blood glucose regulation.

On your plate: four simple strategies

1. Choose fibre-rich carbohydrates more often

Fibre, particularly certain types of soluble fibre, slows carbohydrate absorption. It also contributes to satiety, digestive health and overall dietary quality.

Good sources include lentils, chickpeas, beans, oats, wholegrain or sourdough bread made with wholegrain flour, whole grains, vegetables, whole fruit, seeds and nuts.

The World Health Organization recommends that adults consume at least 25 g of dietary fibre per day (while France's ANSES sets an adequate intake of 30 g per day) and prioritises whole grains, vegetables, fruit and legumes as the main sources of carbohydrates.

In practice, eating legumes regularly and choosing less refined versions of everyday foods will generally be more beneficial than constantly searching for the food with the lowest glycaemic index.

2. Think about the whole meal

Protein, fat and fibre all affect digestion and can influence how quickly glucose enters the bloodstream.

A simple way to build a meal is to include a generous portion of vegetables, a source of protein, carbohydrates adapted to your appetite and activity level, and quality fats such as olive oil, nuts or seeds.

For example, a bowl of rice can be combined with vegetables, tofu or fish and a drizzle of olive oil. At breakfast, wholegrain bread with eggs and fruit provides more protein and fibre than bread and jam alone, helping you feel satisfied for longer and potentially moderating the glucose response.

These combinations also help meet nutritional needs and make meals more satisfying. People who are very physically active may naturally need larger portions of carbohydrate-rich foods.

3. Consider the structure of your food

Whole fruit and fruit juice both contain sugars, but their physical structure is different. Whole fruit provides fibre and requires more chewing, while juice makes it easy to consume a substantial amount of free sugars quickly.

How finely grains are milled, how foods are cooked and how extensively they are processed can also change how accessible starch is to digestive enzymes. An intact grain, rolled oats and finely milled flour will therefore not necessarily produce the same glucose response.

A useful principle is to preserve the natural structure of foods whenever possible, rather than choosing them solely according to the amount of sugar listed on the label.

4. Eat enough and build meals that keep you satisfied

Feeling particularly tired after lunch, struggling to concentrate, becoming hungry again soon after eating or craving sugar in the afternoon are all reasons to look more closely at the composition and size of your meals.

However, these sensations are not very specific. A natural dip in alertness occurs in the early afternoon even without eating, and sleep deprivation can make it more pronounced. Feeling sleepy after lunch does not, by itself, indicate a blood glucose problem, although meal composition is one factor worth exploring.

A meal made up mainly of refined carbohydrates, with little protein or fibre, may produce a faster glucose response and leave you feeling hungry again sooner. Conversely, a meal that is too small may simply fail to provide enough energy.

Sleep, stress and physical activity also influence appetite, alertness and blood glucose regulation. Looking at these symptoms in the context of your overall lifestyle is therefore important.

In practice, if you regularly feel hungry or experience a noticeable energy dip soon after eating, start by looking at what was on your plate: enough protein? Fibre? A portion size that meets your needs?

A snack may also be appropriate depending on your needs: fruit with plain yoghurt, wholegrain toast with cheese, or a handful of nuts.

The goal is to build meals that provide enough energy, promote lasting satiety and support healthy blood glucose regulation throughout the day.

Beyond food: lifestyle matters too

Walk after meals

When muscles contract, they increase glucose uptake, partly through mechanisms that work independently of insulin. A gentle 10–15-minute walk, ideally within 30 minutes after eating, can reduce the immediate post-meal glucose response. The effect tends to be greater when movement begins soon after the meal, although the magnitude varies between individuals.

Maintain your muscle mass

Muscle is one of the body's major sites for glucose use and storage. Strength training, endurance exercise and daily movement improve the body's ability to handle carbohydrates over time. Regularly breaking up long periods of sitting provides additional benefits.

Protect your sleep

In a randomised trial involving 38 women, reducing sleep by approximately 1 hour and 20 minutes per night for six weeks increased fasting insulin and an index of insulin resistance, independently of changes in body fat. Other studies have shown that these parameters can return towards normal after sufficient sleep is restored. Sleep duration and regularity are therefore practical factors in metabolic health.

Consider stress and daily rhythms

Cortisol and other stress hormones influence glucose availability. Circadian rhythms also affect how the body responds to meals. Keeping relatively consistent schedules, allowing enough time for recovery and adapting meals to the demands of the day can all help support metabolic regulation.

Consistent, realistic habits matter more than getting every single day exactly right.

What can biomarkers tell us?

Blood tests can help explore different aspects of blood glucose regulation: how much glucose is circulating in the blood, its average level over several months, and how much insulin the body is producing.

Fasting glucose

The amount of glucose in the blood after a period of fasting. A key marker used in diabetes screening.

HbA1c

Average blood glucose over the previous two to three months, providing insight into longer-term glucose regulation. Results can be distorted by iron-deficiency anaemia (falsely elevated values) or haemolysis (falsely reduced values).

Fasting insulin

The amount of insulin circulating after an appropriate fasting period. It can provide information about the body's insulin requirements, although there is no universally accepted diagnostic threshold.

HOMA-IR

An index calculated from fasting glucose and fasting insulin to estimate insulin resistance.

Triglycerides and HDL cholesterol

Additional indicators of metabolic health and cardiovascular risk.

At Lucis, we look at these biomarkers together to gain a clearer understanding of your metabolic health.

For example, normal fasting glucose can coexist with relatively elevated insulin levels. In this situation, the pancreas is producing more insulin to maintain blood glucose within the expected range. This may point towards reduced insulin sensitivity and warrant further investigation in the appropriate clinical context.

Looking at these results alongside HbA1c and lipid markers provides a more complete picture of metabolic health. It helps identify which parameters deserve closer attention and allows their evolution to be monitored over time.

What about supplements?

Several natural compounds have shown promising effects on blood glucose regulation, particularly in people with insulin resistance, metabolic syndrome or type 2 diabetes.

• Berberine is one of the most extensively studied compounds. It acts on several pathways involved in energy metabolism, including hepatic glucose production and cellular signalling. Meta-analyses of clinical trials have reported improvements in fasting glucose, HbA1c and certain measures of insulin resistance, particularly in people with metabolic disorders.

• Myo-inositol is involved in insulin signalling at the cellular level. It has been studied particularly in women with SMOP (metabolic, ovarian and polyendocrine syndrome, formerly known as polycystic ovary syndrome or PCOS). Several trials have reported improvements in certain metabolic parameters, although results remain variable.

• Cinnamon contains bioactive compounds studied for their effects on glucose metabolism. Several meta-analyses have reported reductions in fasting glucose and, in some cases, HbA1c, mainly in people with type 2 diabetes.

The potential benefits of these compounds depend on an individual's metabolic profile, goals and medical circumstances. Their use should be personalised, with particular attention to possible drug interactions and contraindications.

Berberine, for example, is not recommended during pregnancy or breastfeeding. It can enhance the effects of glucose-lowering medications, interact with other drugs and cause digestive side effects.

As for cinnamon, Chinese cinnamon (cassia) contains coumarin, a compound that can be toxic to the liver when consumed in high doses repeatedly. Ceylon cinnamon contains only trace amounts of coumarin and is therefore the preferable option.

In all cases, seek advice from a doctor or pharmacist before taking supplements, particularly if you are taking medication.

What you can start doing this week

Start by looking at your usual meals. Do they contain enough fibre, protein and healthy fats? Are your carbohydrate portions appropriate for your activity level and energy needs?

Then try adding a 10–15-minute walk after lunch or dinner. This simple habit encourages your muscles to use glucose and helps improve your body's response after eating.

Finally, pay attention to how you feel. Hunger that returns quickly, frequent sugar cravings, pronounced sleepiness after meals or difficulty concentrating may be reasons to take another look at your diet, sleep and daily routine.

The main thing to remember is that our ability to regulate blood glucose changes in response to our habits. The quality of our diet, muscle health, daily movement and sleep all influence insulin sensitivity and how effectively our bodies use glucose.

And this is where a meaningful opportunity for prevention lies: protecting our ability to regulate blood glucose over the years, supporting metabolic health and reducing the risk of chronic disease.

Understanding these mechanisms, knowing your biomarkers when appropriate and focusing on the factors that matter most can help build a more personalised approach to prevention, with benefits that extend well beyond blood glucose.

References

1. American Diabetes Association Professional Practice Committee for Diabetes. (2026). 2. Diagnosis and classification of diabetes: Standards of Care in Diabetes: 2026. Diabetes Care, 49(Suppl. 1), S27–S49. PMID: 41358893.

2. Assurance Maladie. (2025, July 30). Symptômes et diagnostic du diabète. Ameli.

3. Engeroff, T., Groneberg, D. A., & Wilke, J. (2023). After dinner rest a while, after supper walk a mile? A systematic review with meta-analysis on the acute postprandial glycemic response to exercise before and after meal ingestion in healthy subjects and patients with impaired glucose tolerance. Sports Medicine, 53(4), 849–869. PMID: 36715875.

4. Jenkins, D. J. A., Willett, W. C., Yusuf, S., Hu, F. B., Glenn, A. J., Liu, S., Mente, A., Miller, V., Bangdiwala, S. I., Gerstein, H. C., Sieri, S., Ferrari, P., Patel, A. V., McCullough, M. L., Le Marchand, L., Freedman, N. D., Loftfield, E., Sinha, R., Shu, X.-O., . . . Sievenpiper, J. L. (2024). Association of glycaemic index and glycaemic load with type 2 diabetes, cardiovascular disease, cancer, and all-cause mortality: A meta-analysis of mega cohorts of more than 100 000 participants. The Lancet Diabetes & Endocrinology, 12(2), 107–118. PMID: 38272606.

5. Sacks, D. B., Arnold, M., Bakris, G. L., Bruns, D. E., Horvath, A. R., Lernmark, Å., Metzger, B. E., Nathan, D. M., & Kirkman, M. S. (2023). Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus. Diabetes Care, 46(10), e151–e199. PMID: 37471273.

6. World Health Organization. (2023). Carbohydrate intake for adults and children: WHO guideline. World Health Organization.

7. Wu, Y., Ehlert, B., Metwally, A. A., Perelman, D., Park, H., Brooks, A. W., Abbasi, F., Michael, B., Celli, A., Bejikian, C., Ayhan, E., Lu, Y., Lancaster, S. M., Hornburg, D., Ramirez, L., Bogumil, D., Pollock, S., Wong, F., Bradley, D., . . . Snyder, M. P. (2025). Individual variations in glycemic responses to carbohydrates and underlying metabolic physiology. Nature Medicine, 31(7), 2232–2243. PMID: 40467897.

8. Zuraikat, F. M., Laferrère, B., Cheng, B., Scaccia, S. E., Cui, Z., Aggarwal, B., Jelic, S., & St-Onge, M.-P. (2024). Chronic insufficient sleep in women impairs insulin sensitivity independent of adiposity changes: Results of a randomized trial. Diabetes Care, 47(1), 117–125. PMID: 37955852.

The information in this newsletter is provided for educational and informational purposes only. It does not constitute medical advice, diagnosis or treatment.