Hi Chris,
Great question. You remembered correctly that protein intake does increase glucagon. If blood glucose is low and you eat a high protein meal, glucagon can stabilize it by converting some of that protein into blood glucose. Glucagon can also raise blood glucose in the fasted state by breaking down stored glycogen.
The relationship between glucagon and insulin is complex. They’re usually called antagonists, because their functions are opposite, but it gets more complicated.
Insulin drives excess energy into storage and is stimulated most by carbohydrates. Fat is insulin neutral. Protein can spike insulin, but it’s context-dependent.
Glucagon catabolizes stored energy and makes it available to the body. It is stimulated by protein and fat. Carbohydrates inhibit.
Where it gets interesting is that protein stimulates insulin under certain conditions. If blood glucose is high, a protein rich meal will stimulate insulin to prevent gluconeogenesis (creation of glucose from protein), which could drive blood sugar even higher.
However, if blood glucose is low, protein will not stimulate insulin for a very good reason: you don’t want to become hypoglycemic. So, in a fasted state, ingesting protein will elevate glucagon and increase gluconeogenesis, but do nothing to insulin. A spike in insulin would drive already low glucose even lower.
I’m trying to dig up a video that explains this really well. I’ve been quarantined all day with a 2-year-old…but I’ll find it tomorrow for sure.

Thank you for the explanation my man. I have a few more questions, whenever you get to it.

There are a few words I've heard a lot (and even use myself) but don't really understand completely what they mean: metabolize, catabolize, and glycogen. Can you explain them to a college dropout?
If I remember correctly at the Level-1 I was just at, is one of the ways protein can stimulate insulin by eating too much of it at once? Or is that just overeating in general?
So fat is not hormonally-neutral, just insulin-neutral?
How do scientists know all this stuff? It seems so micro and intricate and really difficult to observe in real time.
I think I am set on understanding the why's behind making sure the carbohydrate/protein/fat balance out - at least enough to instruct most of the peeps in the Champions Club. What do you think is the most important layer for me to learn beyond that? Sometimes it's hard to tell when I'm going too far down the rabbit hole with some of this. Like, those tables in the article might as well be effing hieroglyphics or something. But if they help Mr. Malak get healthy then I'll start learning Egyptian.

I know it must be difficult trying to write to doctors and dummies at the same time, but like I said, I think most of it is really simple to understand when you present it like you did.

Okay, here’s the video I was looking for that offers a nice explanation of the role of protein in the insulin-glucagon relationship.
Dr. Benjamin Bikman - 'Insulin vs. Glucagon: The relevance of dietary protein'

This article by Dr. Fung is also really good on protein and insulin: Fat and Hyperinsulinemia

Great questions! I’ll tackle them as best I can.

Glycogen is a big collection of glucose molecules. It’s how we store sugar within our muscles and liver. Your body can very quickly and easily take sugar and chain them together into glycogen. And then it can reverse this process and break glycogen back down into sugar.

Metabolize means to break food down into its most basic units for either energy or building blocks. When we eat, our digestive system takes whole food and turns it into simple sugars, fatty acids and amino acids. If there is an excess of these after a meal, they get moved into storage. Some forms of energy are more readily stored than others. A limited number of carbs can be converted to glycogen, but once that tank is full, the rest gets converted into fat. Amino acids can also be converted to carbohydrates and used for energy or storage.

There are two basic states your metabolism can be in: anabolic and catabolic. Anabolic is when you consume excess calories. Energy (carbs, fat, protein) become building blocks. This is good when excess protein turns into muscle tissue, but not so good when excess energy goes into fat storage. The fed state is anabolic. Catabolic is when you are using building blocks as energy. So, you’re breaking down storage structures like glycogen, fat and even muscle in order to create fuel. This corresponds to the fasted state.

Stereotypically, bodybuilders love the anabolic state and fear the catabolic state. They think of the catabolic state as burning your furniture to keep your house warm.

Longevity researchers seem to fear the anabolic state, as they associate it with obesity, inflammation and cancer. They value the catabolic state, because cellular junk gets cleared out and inflammation is reduced.

I think the truth is somewhere in the middle. We want to build muscle in the anabolic state and burn fat in the catabolic state. A metabolically healthy person should be able to do this.

Protein can stimulate insulin, but it depends a bit on your blood glucose state. The video I linked to above explains it really well. I don’t think this information is widely known, even in the low carb community, because you often hear people worry excessively about too much protein in their diet. Protein’s effect on insulin is probably a concern only for people with medically necessary ketosis. According to the research Dr. Bikman cites, protein has a minimal impact on insulin when blood glucose is low. This is generally true while fasting or on a low carb diet. Dr. Fung points out in the article linked above that excess protein converts to carbohydrates and then stimulates insulin. Sorry, protein is just complicated!

Fat is insulin neutral, but there are other hormones that do respond to fat. For example, it increases appetite regulating hormones like GLP-1 and PYY. Intuitively, we know this because fat is very filling. We don’t tend to overeat on fat or protein.

As for how scientists know this stuff, they often learn from when something goes wrong. A lot of what is known about insulin, for example, comes from people who can't produce it— Type 1 diabetics. Further, a lot of experiments are done on mice where they can genetically alter them to knock out a certain hormone and then see what happens. Continuous glucose monitors are becoming popular among non-scientists who want a better window into what’s going on with their own metabolism. You can find out what foods and lifestyle factors raise your blood glucose.

As for what level of granularity a trainer needs to know… I think it depends. I’m self-taught on this, because I find it really interesting. In the real world with actual clients, you might not need to know any of this to convince a person who is more emotionally driven. For a client who is more logically driven, they might want a level of scientific justification that modern science can’t yet provide. Wouldn't it be easy if we could just point everyone to the CrossFit meal demos and say “just cook that”?

That is insane that the ratio goes from 4:1 to 70:1 when protein is presented in an already-elevated state. That entire video was actually really good, and the visuals helped a lot. Also his point at the end about possibly being weary about protein for someone who's starting with you in an elevated state and steadily progressing them to more as they go makes sense.

Also, your explanations were very helpful in my understanding. Thank you for taking the time to do that!