Fat along with carbohydrates? Better not…
In addition to pure fat digestion, you also need to consider the intake of carbohydrates in the provision of nutrients for the body. As so often, nature always tries to find the easiest way to supply energy. However, the provision of energy by carbohydrates is easier than by fat. Of particular importance is the hormone insulin.
So what happens if carbohydrates and fats are given to the body at the same time?
Well, in parallel to the digestion of fats, the carbohydrates (polysaccharides) are split by the body into ever smaller molecules, until at some point they can be absorbed by the body as simple sugars (monosaccharides). These are ultimately, just like the fatty acids, absorbed in the small intestine and fed to the bloodstream as blood sugar. In response to this increase in blood sugar, the body reacts with the release of the hormone insulin in an effort to lower the blood sugar level. The hormone insulin has, in simplified terms, two functions: it regulates the blood sugar level and transports nutrients into the cells. The greater the increase in blood sugar, the higher the subsequent insulin output. How the body reacts to which kind of food depends on the glycemic index (GI) of a food. The greater the GI, the more insulin is produced, which in turn results in increased nutrient storage in the cells (anabolic process).
As described above, fats and carbohydrates are the main energy sources for the body. However, carbohydrates are easier to use by the body as an energy source. For digestion, this also means that carbohydrates are used more to provide energy, while fats, which are not used for other purposes, are only used when carbohydrates are no longer available. The excess nutrients, whether fats or carbohydrates, are stored in the fat deposits.
If you give the body more calories than it needs (positive energy balance), you build up long-term body fat. Here, the type of nutrients supplied is not crucial. If you take too many carbohydrates, then you build up body fat just as you consume too much fat, because even carbohydrates (and therefore some amino acids) can be converted into fats.
However, the simultaneous intake of carbohydrates with high GI along with saturated fatty acids forms the “worst case”. Tthe carbohydrates drive up the insulin level and then the saturated fatty acids can be stored very easily in the fat deposits. Ultimately, these are exactly the combinations that are highly available in junk food or the typical fattening foods (chocolate, fries, cake, cookies).
On the other hand, if less energy is used (negative energy balance), body fat is reduced as the depot fat is used to supply the body with energy.