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From Yahoo:

I have had type 1 diabetes for 32 year and currently use an insulin pump with Humalog. Meats such as chicken, beef, and pork, at some point, digest into carbohydrates. At what rate or the time does it take for this process to happen?


Proteins are extremely slow to be digested and then are broken down to amino acids, processed by the liver. This then goes mostly to be stored in proteins being synthesized by the body, but some portion of these are eventually converted to carbohydrates. Essentially, very little of the protein that you are eating can be counted as carbohydrates to later raise your blood glucose levels perhaps in the range of 10-25% or so gram for gram. So, unless you are eating huge portions of steak, chicken etc., there is very little effect of the protein, per se, on your blood glucose levels even several hours later.

We used to think that the protein would help slow down the carb absorption, but it is more likely the fat content (that often goes along with most proteins from animal sources) that slows the absorption of the other food nutrients. Also, the more fat contained with the proteins, the slower the whole digestion process. Thus, high fat ice cream with loads of sugars acts as a great bedtime snack and a "lente carbohydrate" to help prevent overnight hypoglycemia.


Additional comments from Betty Brackenridge, diabetes dietitian:

Exactly how much of the protein you eat ends up as glucose in the bloodstream is hard to predict. The amount is probably higher when people eat more protein than their body requires or when they eat a large amount of protein at one time.

Only certain amino acids (the building blocks of protein) can be converted to glucose. This happens some hours after the meal is eaten. The protein must first pass through the stomach into the small intestine where it is attacked by protein digesting enzymes, breaking long protein chains down into separate amino acids. Those are absorbed and enter the circulation. Only later will those amino acids be converted to glucose and then only if they aren't used for more typical "protein uses" like repairing muscle tissue. Exactly how long that all takes is difficult to pinpoint. When the glucose from protein does enter the bloodstream, it is usually several hours after the meal and occurs fairly gradually, not in an abrupt peak like the more immediately available glucose from carbohydrates. For most people, the glucose pattern associated with usual modest protein intake appears to get covered by adjustments to the basal/background insulin. That is why it is not counted by most people who use carbohydrate counting to adjust mealtime insulin boluses.

If you are noticing a significant rise in glucose some hours after eating a high protein meal, it might be due to the protein itself or it may be due to a high fat meal slowing absorption of carb and increasing your need for insulin.

Because this is all so individual, my best suggestion is that you watch for patterns in your blood sugar associated with high protein meals and then experiment with dual-wave or square wave boluses to control blood sugar rises several hours after eating. The exact timing should relate to your actual blood sugar pattern, not to some estimate out of a book. Your bolus ratio for protein should be considerably lower than yours for carbohydrate since only about 50%-60% of protein can possibly be converted to glucose.


Additional comments from Mike Schurig, diabetes dietitian:

Protein will have an effect on your blood glucose if eaten in large amounts. A good rule of thumb to follow is if the protein serving is larger than the palm of your hand, you will want to consider its effect. Roughly 50% of protein might be converted into glucose (in two to three hours after eating), which in turn will affect your blood glucose. Protein slows down the body's use of carbohydrates, which are broken down 90-100% of the time for energy within an hour after eating them.


Additional comments from Lois Schmidt Finney, diabetes dietitian:

If there is high amount of fat present in the meal, it may well take longer than the usual six to seven hours to digest the protein. However, amino acids, the building blocks of protein, are usually digested within three to four hours. It is controversial if and how much of protein intake is converted into carbohydrate. A study done in the 1930s suggested 58%, but that has not been proven. One thing we do know is that for folks with type 1 diabetes, if they have an usually high intake of protein at a meal, they may need more insulin at the meal time to cover the post-prandial rise. If a lot of fat is eaten at the same meal (as have a 1# prime rib steak, when the usual intake is about four to five ounces of protein), short-acting insulin will not cover the rise in blood glucose three to four hours later. If the short-acting insulin is increased, hypoglycemia may result after the meal and then several hours later, hyperglycemia.

The only way we have dealt with that is to ask people that if they want to maintain as close to normal blood glucose as possible but want an occasional "pig out"of protein, to take extra insulin about three to four hours after the meal. I have seen several patients who are willing to do this, and it works out.


Original posting 2 Feb 2001
Posted to Meal Planning, Food and Diet


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Last Updated: Tuesday April 06, 2010 15:09:18
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