Always happy to share my perspective dude. I appreciate your willingness to self-experiment.
Here are my thoughts, keeping in mind I have no scientific background or formal education
Here’s where the theory becomes an issue: things don’t exist in a vacuum.
Are you meaning these two both eat the same amount of meat, but one also drinks a gallon of milk on top of that? That dude is definitely going to get fatter, simply because he’s consuming more FOOD in general.
But if you meant calories were equal, then let’s consider this.
A gallon of whole milk is about 2400 calories. To equate that to piedmontese grassfed sirloin, that’s 64 ounces of steak: 4lbs.
We already said these guys were both eating meat and cheese: imagine trying to eat four POUNDS of steak when you’re already pretty full of meat and cheese? But a gallon of milk? We can make that happen overtime. You’ve most likely done that with a gallon of milk a day.
But then, let’s consider this as well: if trainee A was ONLY eating meat and cheese, he’s most likely in a state of ketosis/fat adapted. The second individual, because of the lactose, will not reach ketosis: he’s taking in 192g of sugar per day. A fat adapted person is simply not going to have the appetite of a carb/sugar adapted athlete, because they aren’t able to generate the insulin spikes that create that hunger cycle. I used to be hungry enough that I ate every 30 minutes: now I can fast for over a day. So, again: trying to get trainee A to eat in the abundance that trainee B can eat in is going to be QUITE an accomplishment.
If, somehow, we could get them to equal calories, then it becomes an interesting situation. There are theories that the body doesn’t have the ability to store extra protein, but there’s ALSO a theory that excess protein can be converted to glucose via gluconeogenesis, but then there’s an argument on if that process is DEMAND driven (the body makes glucose when it needs it) or SUPPLY driven (the body makes it when there’s a surplus of protein)(.
Meanwhile, carbs are rather insulinogenic, and some argue that carbs consumed in the presence of dietary fat shuttles fat to body fat cells. But some also argue that fat helps BLUNT the effect of insulin and can make spikes less sharp.
Here’s where I’m at: trainee A will be a fat adapted athlete. His body uses fat as a fuel source. As long as he keeps eating meat and cheese (I’d prefer eggs myself), he’ll keep giving his body it’s preferred fuel (fat) AND the protein necessary to build muscle.
A NON-fat adapted athlete is a carb adapted athlete. There’s nothing wrong with that, but THAT athlete needs to eat carbs for fuel and protein to build muscle. For them, the only purpose of fat is to keep hormones healthy.
And athlete that eats an abundance of fat AND carbs is simply an obese athlete. You aren’t going to find many obese people out there that are ONLY eating a surplus of carbs or fats: it’s BOTH, typically a combination of oils, salt, and sugar. If you check out ANY junk food, you tend to find those 3 ingredients.
Regarding fructose: I’ve seen too many arguments for and against it. My biggest concern is it’s impact on liver health. As far as I know, fructose does not replenish liver glycogen like glucose does, but I could be wrong.
EDIT: I was glad to see @QuadQueen swing by here, because she actually has the bonafides.


