Keto Diet and Blood Sugar Levels

I have read much on here about Diabetes and the Keto Diet but my question is not addressed.

I know that typically a high fat meal will cause a significant rise in blood glucose about 8 hours later. The Keto Diet calls for lots of fat. Will my blood sugar run higher because of the fat?

I am on a Tandem T-Slim Insulin Pump, and Dexcom G6 CGM.

Thank you.

No, it won’t run higher, it will actually run much lower, that is if you limit your carbs to a 5% range.

The general “macros” for a keto diet are 75% fat, 20% protein, and 5% carbohydrate. You can go up or down 5-10% on these “macros” but the general percentage is what keeps you in ketosis.

When you are following a keto diet, you are making your body burn fat rather than carbohydrates for energy. If you have too many carbs, your body will burn them first. So, it’s best to not give your body a chance to put carbs first and you do that by following the general macro percentage.

It is true, when we are on a regular diet, burning carbohydrates and we have a high fat meal, it can/will effect our blood sugar several hours later - typically raising it.

A keto diet is amazingly different.


You may need to split your bolus, square wave your pump. For up to 50% for the protein grams, of what you would use for carb grams.
It’s always a good idea to do a mySugr miss a meal basal check to get that in order.

This is true when a high fat meal also contains a generous amount of carbohydrates. It is thought that the high-fat content of a high carbohydrate meal slows down the digestion of the carbs and leads to delayed hyperglycemia in people who fail to compensate with their insulin dose to prevent that late BG rise.

My experience of nine years eating a high fat, low carb diet resonates with @Tapestry’s comment above. I find this amazing phenomena a gift. Good luck with your eating experiment, @Nan.

I find a slight variation on this is true.
If you are eating a lot of fat, it will increase insulin resistance.
So you will need more insulin to cover the carbs you eat.
Fat takes a long time to digest so that’s why you see an extension of that effect when you eat carbs mixed with fat.

If you are truly eating low carb, you probably won’t notice the insulin resistance because there are fewer carbs to metabolize.

I don’t think there is any magic diet that will fix all the issues.
High fat diets are not good for your heart, but high sugars are also bad for your heart.
So we need to thread that needle and do what is best for us.

I do a modified moderately high carb and low fat diet. Typically people who follow this are vegetarian or vegan, I am not and my fat consumption is a little bit higher than recommended.

Still I do my best and my sugars are very well maintained and my weight is where I want it to be.

There is no magic pill unfortunately.

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