How To: Know How Proteins, Fats, and Carbs Affect My Blood Sugar

This section is for everyone.  The information is somewhat more applicable to type one diabetics but type twos need to know some of this as well.

You have read a lot about how carbohydrate affects your blood sugar but what is less known is the effect that protein has on your sugar levels.

About a third of the energy from protein is made into sugar. This process is slower than for carbohydrates and can take 2 or 3 hours or more. Delayed blood sugar rises are likely to happen if your meal has a significant amount of protein in it. By this I mean over 3- 4 oz of lean cooked meat, chicken, fish or 3 eggs.

A ready reckoner is to compare the size of the meat you intend to eat to a  pack of cards.  If you have steak the size of a woman’s hand or a deck of cards this is about 3 – 4 oz.  Chicken to the size of your palm plus the first finger joints or fish the size of a woman’s whole palm is about the same. When you have this amount you must give yourself extra insulin one way or another to cover it or you will go higher than you expect after the meal.

These are the average to small portion sizes such as you would be served in a hospital canteen. Restaurant servings can be a lot bigger. When looking at omlettes, quiches and scrambled egg you need to imagine how many eggs may be in there.  Three or more need extra insulin coverage. One egg is equivalent to about one ounce of protein. Big hamburgers eg quarter pounders are easier to recognise and also need extra insulin coverage.

Immediately delivered insulin which covers high and medium glycaemic carbohydrate dishes is no good for covering the much more slowly digested protein. The extended bolus and split bolus techniques familiar to pump users works well however. Using two or more rapid acting insulin boluses can work well and so can using meal insulins with longer action such as regular insulins.

In the UK actrapid is the regular insulin available.  It can be in pen form only from Wockhardt in the form of soluble pork or beef insulin. This is being exported now to several countries and can be used in the Owen Mumford Autopen Classic.  This pen comes in one unit or two unit increments. Genetically Modified Human Actrapid from Novonordisk is still available in vial and syringe form.  Sadly they discontinued their pen actrapid which could be delivered in half unit increments. Pens tend to be easier to carry and syringes can give more versatility over dosage.  It all comes down to personal preference.

These insulin delivery techniques and much more is discussed in Gary Scheiner’s excellent book, “Think Like a Pancreas”.  Gary was diagnosed as a type one diabetic at the age of 18. He became an exercise physiologist and diabetes educator and is particularly enthusiastic about pump therapy.  His book covers important details regarding insulin use that are not always covered in much depth in diabetic clinics. For anyone on insulin I recommend this book so you can get the best out of your current insulin regime and consider other helpful strategies to optimise control of your blood sugars. This book usually gives several different options regarding problem solving.  It goes into more depth about insulin than Dr Bernstein’s book regarding insulin use and takes a neutral stance on dietary aspects.

Meals that have a high glycaemic index or load will usually need a standard food bolus such as supplied by novorapid/novolog and humalog as the food is quickly converted into sugar in the blood stream.     Examples of these are bread, cereals, potatoes, parsnips, cooked carrots, rice, biscuits, cakes, tropical fruits and sweets.

Meals that have a very low glycaemic index / load may require a method to lengthen out the insulin delivery time just like meat.  Examples of these sorts of foods are pasta, especially with creamy or cheesey sauces like lasagne or spaghetti carbonara. Very high breakfast cereals eg all bran.  Curries made with lots of fat eg kormas. Battered fish and chips. Chocolate, most dairy food and nuts.

A major difficulty with the glycaemic index is that it gives artificial categories of supposed blood sugar rises for a given amounts of carbohydrate containing foods.  One problem is that these tests were done on healthy non diabetics who still have a phase one insulin response. Both type ones and type twos do not have this capacity to immediately release stored insulin. The rate of absorption is also dependent on the temperature of the food, bite size and what it is eaten with and in what order.

To really know what is going on in your body you need to do extensive testing to get the best results for each meal you eat.  This involves testing every 30 minutes or so for three or more hours after each meal  you eat.

You can only test a food accurately if your baseline blood sugar is normal. Even then insulin sensitivity can vary throughout the day. Typically you are quite insulin resistant at breakfast and are at your most insulin sensitive in the afternoon.

Although this sounds a terrible chore most people only eat about 20 different meals on a regular basis and some a lot less.  Please don’t ask me what to do if you are a type one restaurant critic!

To give smooth protein curves it is best to eat some of the protein and fat before you eat the carbohydrates.

If you are having a high glycaemic item leave it till the end of the meal if possible.  Can you add some fat to it?  This will reduce the rate of absorption. Eg fruit and cheese, potatoes with butter and cream, cake and cream.

Lots of fat in the diet improves the taste, fullness after meals, vitamin absorption and slows down carbohydrate induced sugar spikes.

Other Food Tips

If you are going to have a snack consider low glycaemic carbohydrates, protein and fat so you are fuller for longer and sugar spikes are minimised. Eg full fat yoghurt, crackers and peanut butter, toasted cheese with butter on thin sliced wholemeal bread.

In a restaurant you can take your regular insulin once the waiter has taken your order as long as there is bread on the table. You only eat this in an emergency however!

If you take rapid acting insulins take it with the starter if you have a normal blood sugar, your main meal if you are low and when the waiter takes your order if you are high.

Tell the waiter you are diabetic and need food right away if you have been waiting for a time or feel low.

It is best to let toddlers eat and then gave them rapid acting insulin to cover what they actually ate.

Quick Quiz:
1. Three of the following make food digest more slowly. Which one does not?
a A lot of sugar or starch in the meal.
b A lot of fat in the meal.
c A lot of protein in the meal.
d Delayed stomach emptying also called gastroparesis.

Have you got it?
1.A is correct. Protein and fat make meals digest more slowly. Sugar and starch are digested quickly. Gastroparesis is when stomach emptying is delayed or erratic due to nerve damage from chronically high blood sugars. Like foot neuropathy it can develop after around five years of having poorly controlled blood sugars.

Acknowledgements & Reference Info:

Where to Next?
Please continue to the How To: Know What Oral Medications I May Be Offered for Diabetes section.