Carbohydrates are one of the three macronutrients. They vary from simple sugars (2 sugar molecules linked together) to complex carbohydrates (longer chains of simple sugars). As most of us are aware, simple sugar is digested and absorbed very fast into our body while complex carbohydrates take longer. As sugar reaches our blood, the hormone insulin is released to stimulate the sugar in your blood to be taken up and stored in your liver, fat, and muscle. Having blood sugar spikes and frequent insulin responses can stress your body and negatively affect your health.
There are two scientific facts that I would like to highlight for this module:
First, our genetics play a significant role in how we respond to sugar. A very interesting study continuously measured blood sugar in a group of diabetics. They do not have a fully functional insulin response so eating something with simple carbohydrates like white bread should have rapidly increased their blood sugar. However, it turns out some diabetics can eat white bread without getting a fast rise in blood sugar levels. They even observed that one person had a very negative response (a fast increase of blood sugar) in response to tomatoes! Tomatoes are in general not bad and the lesson to learn is to be aware that the same food with carbohydrates can have a very different response when different individuals eat them, and our different genetic makeups are a big factor in this. We are not able to predict nutrition yet using genetics so it up to us try to learn this about ourselves.
Reference:
https://www.cell.com/cell/fulltext/S0092-8674(15)01481-6
Second, insulin is actually not the only way the body can stimulate sugar removal from your blood. During exercise and activity, there is an insulin-independent system that transports sugar into your muscles to make sure they can keep working at full capacity. So, if you ingest simple carbohydrates immediately before (10-15 min), during, or immediately after (within 30 min), no insulin is released and instead of a negative health effect, it can ensure a strong performance in your activity. If you eat the simple carbohydrate earlier (ie 30-60 min) before activity your insulin will respond and remove the sugar from your blood and you could actually start the activity with low blood sugar and this is not optimal. Timing when you eat a certain macronutrient is what we refer to as periodization. If you eat simple carbohydrates it matters “when” and they should, for example, be timed together with activity.