In the last module, we discussed the macronutrients. Here’s a quick summary of what you learned:
- When eaten, proteins are broken down into amino acids, carbohydrates into monosaccharides and fats are digested as triglycerides which are 3 fatty acids bound to a glycerol backbone
- These are absorbed from the small intestine. Carbohydrates and proteins are taken to the liver which will either take them up and use them for something (its own energy, conversion to glucose if galactose, fructose or amino acids), store them as glycogen or allow them to be taken into the blood
- Fats, when digested use the lymph system to bypass the liver and enter the blood as chylomicrons before being transported around the body, the contents of each chylomicron being taken up by cells which need them. The near-empty chylomicron then enters the liver to be processed and repackaged
- Blood glucose and amino acid levels are controlled by insulin and glucagon
- The fats we eat affect our health differently, and so fat sources should be eaten in balance
- The carbohydrates we eat largely don’t matter mechanistically, though a large fructose intake may be harmful, and of course we need to consider the impact food choices have on our dietary adherence
- Fats and glucose can be used for energy
- The fat you store is largely the fat you have eaten, but this does not mean that eating fat causes fat gain, or that eating a low-fat diet means fat gain cannot occur
- You learned how to estimate your need of fats, carbohydrates and protein