If you’re looking to increase your nutrient intake and find what does what, you’ll probably see that carbohydrates are what give us energy (with a bit more coming from fat), and protein is what allows us to grow, build muscle and repair injury. This is all true, but what you might not realize is that protein also has a role to play in your body’s energy levels.
To be precise, you can get four calories of energy from every gram of protein you eat. That’s not dissimilar to what you get from carbs. The trouble is that it’s a lot more difficult for the body to process the energy in protein. As protein’s growth and repair functions are more important, as long as you’re getting enough carbs and fat, it won’t bother making the extra effort to use protein for energy.
The energy in protein comes from amino acids. It’s amino acids that are responsible for most of protein’s roles in the body. There are amino acids that build and repair skin, bone and muscle. Then there are some that work on your metabolism and various enzymes. The amino acids that are left over after all that are used in hormones and neurotransmitters.
Amino acids actually look a lot like glucose when you examine their chemical structure. Glucose is a type of carbohydrate. Convert amino acids into glucose, and there’s your energy. There’s a problem, though. Amino acids also contain nitrogen. You can’t use them as glucose until the nitrogen has been removed, adding an extra, time-consuming step. That’s why it’s a lot more efficient just to eat a carb.
Using protein for energy does have some advantages. Carbs don’t always last long, but the extended process that converts protein into energy means it may have a more lasting effect once it is produced. There are disadvantages as well, however, and it’s not just running out of protein for growth. A byproduct of the protein to energy process is ammonia, which can create fatigue when it builds up in your muscles.
Your body isn’t going to use protein for energy unless there’s no other choice. If you’ve run out of energy from carbs and you’ve burned all your fat, it may be used as a stopgap measure to keep you going until you can get more. It’s an important part of understanding how your body works.
