When talking about sugar, it’s important to first recognise what it is.
A carbohydrate is a type of macronutrient that is primarily an energy source for the body. The small intestine breaks down this compound and converts it into glucose, signalling the pancreas to produce insulin, a hormone that carries glucose from the blood to cells in the body for energy.
Carbohydrates can be broken down into simple sugars and complex starches.
Simple sugars are digested more quickly and make it into the bloodstream in a shorter time, meaning they build up to a high level at a given time. Starches are digested more slowly and arrive at the bloodstream at a steadier pace. Think of table sugar or figs for simple sugars, pumpkin or potatoes for starch.
While eating either complex starches or simple sugars, pairing them with compounds such as soluble/insoluble fibre or fat can slow digestion and thus mitigate this spike in blood glucose.
The other macronutrients, fat and protein, also carry energy for the body, but the energy they carry is less bioavailable (our bodies have to work a little harder to access them). It is possible for our bodies to rely solely on fats and proteins for energy, but this requires our bodies to build up higher levels of certain enzymes, which will make the body feel very tired for a certain period of time while we adjust -- this is precisely what happens in the first 2-4 weeks of a ketogenic diet - it feels very tired until the body adjusts.
Fats and proteins have other important functions, such as helping absorb nutrients, produce important hormones and enzymes, build muscle, bones, skin, and blood. Carbs on the other hand, are purely fuel for the body.
When people refer to refined sugar as “empty calories” what they mean is an intake of energy without any micronutrients or other benefits.
When the body experiences a high spike in blood glucose it also spikes insulin production to carry this energy to the cell. Sustained spikes over time can be very damaging to the pancreas, which is in charge of producing insulin, and can lead to the body developing insulin resistance, a precursor to diabetes.
Lots of highly bioavailable carbohydrates make up a high caloric diet. Eating a high caloric diet leads to higher levels of LDL (low-density lipoprotein) cholesterol (often considered the “bad” cholesterol), which often means your body will have lower levels of HDL (high-density lipoprotein) cholesterol (the “good” cholesterol). The buildup of LDL cholesterol in the blood vessels over time can cause the insides of the vessels to narrow, which can block blood flow to and from your heart and other organs. This blockage is what causes chest pains, strokes, and even heart attacks.
When it comes to balanced healthy nutrition, our goal, therefore, is to intake the energy we need from the three macronutrient without spiking blood glucose levels (through slow absorption) while also ingesting sufficient levels of a wide variety of micronutrients to support our body’s different needs.
The ability of a food source to increase blood glucose levels is measured by the Glycemic Index (GI), which shows the impact that one gram of a certain food has on the blood. This impact can be altered, as mentioned above, if multiple compounds enter the digestive system at the same time, slowing the breakdown and thus the speed and intensity with which the glucose enters the bloodstream..
For example, while a strawberry or an apple are a substantial source of simple sugars, the soluble fibre in these fruits slow down absorption and allow our bodies to enjoy the energy, as well as the vitamins (micronutrients) in the fruit without raising our blood sugar levels.
Soluble fibre dissolves in warm water and turns it into a gel, which also leads it to break down slower, together with the sugar.
A cup of Coca Cola on the other hand, is a direct injection of highly bioavailable simple sugars that immediately break down and enter the bloodstream. You can often feel your heart race as a result.
A cup of strawberry or apple juice (that has had the fibres removed) will have almost the same effect as a cup of Coca Cola, as there are no fibres or other compounds to help slow the breakdown and absorption of sugars. (Now, think about these popular “juice cleanses” - of course they feel good, the brain rewards us when you give the body bioavailable energy like sugar)
When assessing your diet, it’s important to consider your wellness goals and the impact of the contents of your digestive system on your path to reaching these goals.
Effective marketing by the commercial food industry has severely simplified much of this nutrition information, highlighting convenient facts that encourage the consumption of certain products over others without proper context.
For reference, table sugar’s glycemic index number is 58-65.
You would be surprised looking at the glycemic index of foods that are marketed as healthy, such as fresh grapes at 59, while Coca Cola is at 63 and chocolate (commercial) is below 10 (the starch and fat slow down digestion despite its sugar content).
Even when looking at sugar alternatives, it’s worth paying attention to other information on the label and doing further research. Evaporated coconut flower nectar, or coconut sugar, for example, has been reported to be as low as 35 and as high as 54.
Image Credit: coconut nectar, https://carazuc.wordpress.com/
The GI of a food or meal is influenced by a number of factors, including the type of sugar it contains, the structure of the starch, the cooking method, and the level of ripeness.
Sugar on its own is not evil. It is just fuel. Over-fuelling your body in one quick spike is dangerous, so you need to pay attention to what you eat it with. This is true regardless of which type of sugar or starch you consume, and whether it comes in a bag of sugar, in a grape, in an apple, tomato, potato or rice.
When it comes to weight loss, A 2019 review of 54 studies concluded that low GI diets reduced hemoglobin A1C (a long-term marker of blood sugar control), body weight, and fasting blood sugar levels in people with prediabetes or diabetes (-Healthline).
A low GI diet can lead to fat loss, but it is not the main contributor to fat loss.
For effective fat loss, your body must be in a state where it believes it needs to spend its energy storage to keep you going, while not missing key micronutrients from your diet. In simple terms, putting your body in an energy deficit.
This simply means spending more energy than you are taking in. This is the key to weight loss, although optimisation also takes into account three other factors: healthy balance of protein, fat, and micronutrients (not missing anything your body needs), an optimal size of the deficit, and dynamics your body can perform in which is more inclined to go through a variety of energy sources, such as ketosis.