That brief surge of energy that swells in us after eating a large sugary treat, commonly known as a sugar rush, is due to a temporary rise in blood sugar. Blood sugar spikes occur when your blood sugar first rises and then falls sharply after you have eaten and are linked to certain types of food.
What is blood sugar?
The widely used term “blood sugar” is a misnomer, as it refers to glucose. During digestion the body breaks down carbohydrates into a simple sugar called glucose, which then enters the bloodstream. Apart from glucose, other sugars are also present in the blood. Food contains several types of sugar, such as fructose from fruit and lactose from milk. Contrary to what the name implies, table sugar is not a simple sugar, as it consists of equal parts glucose and fructose.
Blood sugar or blood glucose level refers to the amount of glucose present in the blood. Glucose is the main source of energy for the cells in the body and is carried to each cell in the body through the bloodstream.
Blood sugar spikes:
Blood sugar spikes are often caused by eating too much food containing carbohydrates, which after digestion enters the bloodstream in the form of glucose. As the amount of glucose in the bloodstream rises, it sends a signal to the pancreas to release a hormone called insulin, which acts as a key to unlock the doors of different cells in the body. This allows glucose to exit the bloodstream and enter the cells, where it is used as the primary fuel for energy or stored as fat for later use.
Without enough insulin, glucose keeps floating around in the bloodstream with nowhere to go, causing levels of blood glucose to become increasingly more concentrated. Too high levels can lead to serious health problems and cause damage to blood vessels, nerves, and organs. Over time your body may not be able to lower blood sugar effectively, which can lead to insulin resistance and type 2 diabetes.
Insulin resistance refers to the inability of cells (resistance) to respond properly to normal circulating concentrations of insulin. To maintain a normal concentration of glucose in the blood, the pancreas compensates by secreting increased amounts of insulin. However, compensating for insulin resistance by an increase in insulin release is effective only temporarily. As insulin resistance increases, impaired glucose tolerance develops. Ultimately, failure or exhaustion of the pancreatic insulin producing cells results in a relative decrease in insulin secretion.
In diabetes, the body has an inability to properly use glucose as there may not be enough insulin, or it isn’t working properly (insulin resistance), and as a result cannot naturally regulate blood sugar levels.
Occasional sharp spikes in blood sugar levels don’t mean you have diabetes, as it is normal for blood sugar levels to rise after eating a meal high in carbohydrates. While infrequent spikes are not regarded as a problem, regular spikes in blood sugar levels are problematic.
Daily roller coaster rides in blood sugar levels have detrimental effects on the body. A few examples are:
- High blood sugar levels stimulate high insulin secretion. With such regular spikes, cells become less and less sensitive to the insulin signal.
- Daily spikes in blood sugar levels fuel inflammation in the body. High blood sugar triggers a reaction called glycation whereby glucose is attached to proteins and certain fats. This contributes to increased levels of inflammation.
- The refined carbs that trigger the biggest surge in blood sugar levels are also typically the most fattening.
Unhealthy refined carbs have a high glycemic index, which means fast digestion, coupled with rapid glucose absorption, to create spikes of high blood glucose levels. A diet high in high-carb foods, and low in blood sugar balancing nutrients such as protein and fiber, results in higher than usual insulin levels as the body tries to lower blood sugar levels. The main dietary sources of refined carbs are white flour, white bread, white rice, pasta, breakfast cereals, pastries, snacks, sweets, sodas, and added sugars.
Over time high insulin levels can promote fat storage. When blood sugar spikes and the excess energy is not burned, the body converts the extra glucose to glycogen (the stored form of glucose that is made up of many connected glucose molecules) which is stored in the muscle tissue and liver, and as fat stored in the adipose (fat) cells in the body.
Sources of healthy carbs:
Natural, unprocessed carbs not only provide energy giving glucose, but also healthy vitamins, minerals, fiber, and phytochemicals.
Healthy carbs have a low glycemic index, which means it gets absorbed slowly and helps to stabilize blood sugar levels.
- Vegetables are healthy sources of carbs, as vegetables also contain vitamins, minerals, antioxidants, and fiber.
- Fruits also contain fiber, vitamins, and minerals, as well as different antioxidants.
- Whole grains that contain all parts – bran, germ, and endosperm – of the original grain are digested slowly and do not cause sharp spikes in blood sugar levels.
- Beans and lentils are very healthy sources of carbs, as they contain minerals, fiber, protein, and complex carbohydrates.
- For a healthy diet, it is best to stick to whole, single ingredient foods.
How to manage blood sugar levels:
A balanced meal is composed of all three macronutrients, namely carbohydrates, protein, and fat. Protein and fat as part of a balanced diet have a minor effect on blood sugar levels in healthy people.
Protein plays an important role in glucose absorption in the body as it takes longer to digest, slowing down the absorption of glucose into the bloodstream.
Fats in the diet does not elicit the release of insulin. Fat in fat cells serves as an energy store for the body.
A scientific way to manage blood sugar levels, based on studies in this regard, was developed by Dr Mario Kratz, the founder and director of Nourished by Science. (see attached poster)
He has developed six strategies to help avoid blood sugar spikes, without reducing carbohydrate intake:
Minimize foods with a high glycemic index: The glycemic index (GI) is a measure of the response of blood sugar to 50g of different types of carbohydrates, compare to the response to 50g of glucose, and is a rating system for foods containing carbohydrates. It indicates how quickly each food affects your blood sugar (glucose) level when that food is eaten on its own, in relation to the effect of glucose. Replacing high GI foods with low GI foods could lower blood sugar levels throughout the day without avoiding carbohydrates, for example at breakfast replace your cornflakes with a porridge made from rolled or steel-cut oats or use sourdough rye bread instead of white bread.
Eat starchy food after retrogradation: When starchy foods are cooked and eaten right away, most of the starch is broken down into glucose, causing a spike in blood sugar levels. However, when the same food is allowed to cool down overnight and eaten the next day, some of the starch adopts a different structure which are known as resistant starch, as the starch becomes resistant to digestion. This process is called retrogradation.
Starch is digested and absorbed in the small intestines. It is broken down quickly during the digestive process, resulting in a large rise in blood sugar (glucose) levels and insulin levels. 100 grams of starch give the body about 400 calories.
Resistant starch is not fully absorbed in the small intestines but is digested much slower through fermentation by intestinal bacteria in the large intestine (colon), like what happens with fiber in the diet. This results in 100 grams of resistant starch giving the body about 200 calories, half the amount of “normal” starch.
The health benefits of resistant starch include lower blood sugar levels, with less insulin being released. It also helps to curb appetite, firstly as the amount of nutrients is released more slowly into the bloodstream, and secondly it has less calories per gram than other starches. It increases feelings of fullness, further reducing the appetite. Resistant starch also assists with healthy digestion, as it feeds the friendly bacteria in the colon.
Don’t eat “naked” carbohydrates: Carbohydrates are called “naked” when they are eaten on their own without much protein, fat, or fiber. As a high-carb meal causes a spike in blood sugar levels, adding a protein to the meal will strongly reduce the blood sugar response. Adding some fat or fiber to the meal will also assist, but to a lesser degree than adding a protein. For example, adding a boiled egg to your easy Sunday morning breakfast of toast and jam will reduce the blood sugar spike. Foods with a high GI can be paired with a serving of non-starchy vegetables, such as onions, leeks, fennel, celery, leafy greens, and cruciferous vegetables such as broccoli and cabbage.
Add vinegar to high-carbohydrate meals: Research shows that having vinegar with or before a high-carb meal can substantially lower the blood sugar response. In the (short-term) studies two tablespoons of vinegar diluted in water was used but is not advisable over the long term due to vinegar being a strong acid – which may affect the enamel of your teeth, the mucus membranes in the mouth, the esophagus, or the stomach. Rather have vinaigrette with a salad or some pickles with your meal. Most of the studies used apple cider vinegar, but according to Dr Kratz any vinegar will do.
Use the second meal effect to your advantage: The second meal effect refers to the fact that, whatever we eat during a specific meal, affects how the blood sugar would respond at the next meal. This means that the type of carbs eaten at one meal, for example a high-fiber low GI meal, will lower the blood sugar response at the next meal. The opposite is also true, when you eat a high-carb meal your body gets ready to handle more carbs at the next meal. The second meal effect supports the incorporation of a serving of protein and a source of fiber into every meal to keep blood sugar responses on a more even keel.
Go on a walk after a meal: Muscle cells that are being exercised can also take up glucose from the bloodstream in a way that is independent of insulin. Studies show that muscle contraction after a meal, ideally through exercise within 30 minutes after completing a meal, substantially lowers the increase in blood sugar levels, even if it is just a walk around the block for 10 or 15 minutes. Kratz says the longer the exercise the better for meals rich in high GI foods.
Conclusion.
Research shows that the roller-coaster ride of regular spikes in blood sugar levels is detrimental to your health in many ways.
The advice from Dr Kratz is to be aware that high-GI foods raise blood sugar the most and to use one of these six strategies to counter it, whichever one is the most convenient.
References:
Protein and blood sugar: How protein affects blood glucose. Published 29 December 2021. Nutrisense. (www.nutrisense.com)
Dietary protein and the blood glucose concentration. Published May 2013 in the journal Diabetes. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
Do fat and protein turn into glucose? Published online. Livestrong. (www.livestrong.com)
How to recognise and manage a blood sugar spike. Updated 21 July 2022. Healthline. (www.healthline.com)
Normal glucose levels after eating. Reviewed 16 March 2023. Healthline. (www.healthline.com)
What are normal blood sugar levels for people without diabetes. Updated 21 June 2022. SIGNOS. (www.signos.com)
How to avoid blood sugar spikes (without reducing carb intake). Published 23 March 2023. Nourished by Science. (www.nourishedbyscience.com)
The dietary glycemic index: Everything you need to know. Published 24 January 2023. Nourished by Science. (www.nourishedbyscience.com)
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