Can Glucose Levels Increase with Protein and Fat?

The question of why glucose levels can climb when eating protein combined with fat is likely the most common one I’ve heard over the past five years. Here are some of my thoughts:

1. Glucose levels are highly variable across the population for reasons that are only now becoming clear. For example, a recent paper found that differences in body fat (i.e., more visceral fat) and insulin secretion could predict people having more variability in glucose levels.
2. My lab is actively working on a project to quantify the degree to which people have an increased glucagon response to protein (and carbs and fat). We’ve already found that some people have both higher glucagon and GLP-1 levels after drinking protein. We haven’t yet identified reasons for this, but, like the previous paper mentioned, it may be due to fat storage differences. It might also be due to insulin resistance differences in the alpha cells (i.e., those that produce glucagon). Regardless of the stimulus, anytime glucagon goes up, blood glucose will soon follow. 
3. Other non-nutrient signals can have a powerful effect on blood glucose; caffeine is a great example. Caffeine elicits an increase in blood glucose even when a person consumes a low-glucose meal.
4. Certain lifestyle variables also have a powerful influence over glucose responses to nutrients. Sleep deprivation increases cortisol and epinephrine, which will act in concert to push up glucose and perhaps even amplify the natural glucagon rise that occurs with protein consumption.

Clearly, different people have varying blood glucose responses to protein combined with fat. For the reasons mentioned above (and likely more), this should be expected. For those who experience an uncomfortable rise, other than being mindful of the points above (i.e., sleep, caffeine, etc.), you could try drinking a shot of apple cider vinegar in water prior to consuming protein+fat together. Even if you already take ACV at other times in your diet, consuming it shortly before a meal or shake with a high protein and fat content may very well provide you with more benefit. 

I hope we can all appreciate the complexity and variety of our bodies. As a scientist, questions like these are my bread and butter (but hold the bread).

References

1. https://pubmed.ncbi.nlm.nih.gov/35016041/
2. https://pubmed.ncbi.nlm.nih.gov/18469247/