Protein – The impact on blood sugar & training

I don’t know about you but when I was diagnosed with diabetes, the intelligent and well-meaning diabetes educators only really talked to me about how carbohydrates will effect my blood sugar. So naturally, I started off with the impression that all I had to do was count carbs and bolus to keep my blood sugar under control. Boy, was I wrong! 

I first started to get an inkling that my first impression was wrong when Marty and I went on our honeymoon to Costa Rica. Everything was going fine for the first few days but about half-way through our trip, my BG spiked over 250 and I couldn’t get it to come back down no matter how much insulin I injected or how many times I changed my infusion site. Now, if you’ve never been to Costa Rica, you may not know that one of the staple meals there is rice and beans. We had so many different styles of rice and beans while we were there and they were all amazing, unlike anything I had tried before! They also have some of the freshest and tastiest fruit, pineapples, mangos, etc. I’ve ever had in my life. Lots of blood sugar spiking goodies to say the least! When my BG sky rocketed up and refused to come down, I thought I would be fine just eating things without carbs like fish, shrimp and eggs. No matter what I did, my BGs were stuck sky high despite doing a lot of walking around and other physical activities like snorkeling and swimming. At the time, I was certain that my insulin must have gone bad. 

When I got back home and saw my endocrinologist, he was skeptical that the insulin would have gone bad and I started to consider other possibilities to explain what happened on our honeymoon. Not long after, a friend asked me about how protein impacted my BGs and I had no answer for him so I got curious and started to do some research. What I found was that protein is eventually converted to glucose in the body, just much more slowly than carbohydrates. I decided to do some self experimentation and started incorporating some meals into my diet that were mostly or all protein to see what effect they would have. Sure enough, without injecting any additional insulin (other than my basal), my BGs would gradually rise. This also explained why I was having so many high BGs at night. A typical dinner for me at the time would have been either lean chicken or fish with either asparagus, zucchini, or a mixed green salad. They were really low carb meals but as soon as the insulin I took to cover the carbs wore off, the protein would hit, my BG would spike and my pump would wake me up. I was like a sleep deprived zombie back then! 

These days, I make a point to bolus for my carbs and my protein at meals. I find that if I bolus for carbs about 20-30 minutes before a meal and bolus for protein after I’m done eating or during my meal, I have much better BG numbers most of the time.* 

I will sometimes use the delayed effect of protein (and fat) on BGs strategically to help prevent lows during a longer workout as well. Now, I wouldn’t recommend having a steak before a run (that would upset my stomach and probably yours too) but I have certainly used a protein shake or a little bit of nut butter as a pre-workout snack**. I also typically keep my portions pretty small due to the Law of Small Numbers so they can be easily corrected if I misjudge something. 

All in all, everything affects everyone a little bit differently and what works for me, may not work for you. I would recommend self experimentation, under your doctor’s supervision, to see what works best for you with protein and training. 

Keep moving forward!

For additional information on protein and how it impacts blood sugar, I really enjoyed the Juicebox Podcast Episode #263 Diabetes Pro Tip: Fat And Protein.

How do you manage protein?

*I’m on the Medtronic 670G closed loop system. I take it out of automode and into manual mode to bolus this way. Entering “phantom carbs” (carbs that you didn’t actually consume) will mess up the algorithm and in my experience, automode isn’t strong enough to prevent a rise in BG from a heavy protein meal if you only bolus for carbs.

**Timing is everything and you need to know when the protein will hit your BG and then time that with your workout so it hits as the exercise begins to lower your BG. Here is an example of one of my workouts where you can clearly see this effect.

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The content on this site is not intended to be medical advice. Always consult your doctor before beginning a fitness regimen or adjusting your diabetes management strategy.

Published by Jenny Nat

5 thoughts on “Protein – The impact on blood sugar & training

  1. Pingback: 3/28/2020-Ride
  2. Pingback: T1 Diabetes Myths

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