All Type 1 diabetics I know were taught at diagnosis that protein is a “free” food and doesn’t need insulin. But, if protein contains no carbohydrates, why does it increase blood glucose?
Short answer:
Gluconeogenesis - the process of converting another substrate (e.g. protein) to glucose.
Which means, “New Glucose Creation”.
The process of protein being metabolized stimulates the release of 2 hormones - insulin and glucagon.
☑️ Insulin is secreted to stimulate protein synthesis – the uptake of amino acids into muscle cells.
☑️ Glucagon is secreted to stimulate the uptake of amino acids into the cells of the liver.
In a person WITHOUT diabetes, the release of these two hormones ensures the amino acids are used for protein synthesis, but blood sugar doesn’t drop to low levels, even if the meal was low carb. Therefore, blood glucose levels remain reasonably stable during protein metabolism. The insulin and glucagon cancel each other out in terms of their effect of blood glucose.
But, in people WITH diabetes, the release of glucagon without insulin (or limited production) can cause blood sugar to rise over several hours after consuming protein. This is due to the glucagon directly raising blood sugar, but also due to that with the absence of insulin, it increases the amount of amino acids that are used for gluconeogenesis.
Here's a visual of how our bodies respond to carbs, protein and fat...
The very bottom of the graph would represent zero impact to blood sugar and very little would reside there. Everything we eat has some impact to blood sugar. The biggest impact is of course carbs - they raise blood sugar the most and quickly. But as you can see, protein does raise blood sugar, it's just less drastic and over a slower, longer period of time. And lastly, fats impact blood sugar the least. In fact, fats can slow down the body proesssing protein - not stop it, simply delay it or prolong it. Ex: if you eat an 8 oz lean filet mignon steak your body will be done processing it in about 5-6 hours. But if you eat an 8oz fatty ribeye steak, it will take about 10 hours to process it because the fat slows the whole process down.
A diabetic might think, “I’ll just lower my protein intake to stop this rise”. This isn't a good solution. There are essential amino acids (proteins) that we must consume to live optimally. You NEED protein - don’t cut proteins for the sake of trying to stabilize blood glucose. The key is to learn the timing of how your body processes proteins, when you start to see the rise, and combat it with proper insulin dosing. Regular insulin is a fantastic tool to help with protein rises because its profile very closely matches the timing of the protein being processed.
The next graph I'll post is a visual of how different insulins work. Pay close attention to the rapid-acting and Regular insulin - look at when they peak and how long they last overall. Now look again at the graph above that shows how carbs and protein are processed by the body. Notice how similar they are? This is why rapid-acting insulin works so well for carbs (even low carb foods) and why Regular insulin works so well for protein . With that said, I know a lot of folks that can use Regular only for low carb high protein meals. Regular tends to be more forgiving since it doesn't have such a sharp onset that you're trying to time and match to what and when you eat.
An alternative for someone on a pump is to do a dual wave bolus to cover the carbs you eat now, and then more insulin a couple of hours later to deal with the protein. Or for someone doing shots but without access to Regular insulin, you can do the same idea... give a shot upfront to cover carbs and a second shot later for protein. However, Regular insulin is the perfect tool for protein!
Please note: this post doesn't cover gluconeogenesis in all it's glory. It's a complex process. I'm only covering it regards to how it can spike blood glucose in a diabetic.
