Please explicitly frame your exact physiological “difference” criteria? Exercising, what level of MET if exercising, rested, OMAD, rMBR (resting metabolic rate), MPS, mTOR AUC, Gluconeogensis, eating with what other foods and their specific nutrient profile/qty.
In a rested state, we already know 80g of beef protein in one bolus, there will be significant EAA still in the bloodstream at 8hrs by the fact there are still elevated levels of leucine at 5 hrs at only 30g beef protein (74 kg young male reference above paper milk vs beef). And a significant amount (depending on metabolic needs, especially rested) will be converted to glucose, and if in excess, into fat stores. Even if you take 0.4g/kg base needs (the above milk vs beef study, 30g/74kg = 0.4g/kg), 80g protein would be the base needs of a 200kg person. Clearly, excess. How long would that take to clear out, maybe days!
We also know that even 40g beef protein, there will be likely still be EAA in the bloodstream at 5hrs. What is happening after those EAA leave the bloodstream…they are taken intracellularly to be processed by mito for various structural/homeostatic needs, but there is a KINETICS to this process too…taking say many many hours more. So what levers of the physiological response are you wanting to understand/manipulate?
I don’t have this exact scientific physiological answer, but for the average person, it’s “probably metabolically better” to take 40g split over 2 sessions with 4hrs in between. But your singular scenario is quite a large beef protein challenge over such a short period of time before next bolus, that it MAY INDEED NOT matter at all!!
At some point, with sufficiently small beef protein intakes, metabolically it would likely tease out the separation of the ingesting intervals.
If one were doing massive MET’s, then I’d say the separation between a singular 80g post work out bolus, vs 40 g post workout, and 40 g 4 hours later might elicit a noticeable metabolic differential signal.
158g of beef (30 g protein) as per above milk vs beef paper, is about 455 calories. So scaling to your 80g beef protein example (421g of beef), this would be 1200 calories.
Someone doing very high MET with high skeletal lean body mass/muscle, would surely consume the bloodstream EAA at a far higher rate than sedentary. The leucine/time curve post workout would look very much different, flatter, returning to baseline quicker. But then, a massive MET workout would generate massive mTOR on top.
So in this scenario, I still think it’s better to split the 80g into 40g, then 40g 4 hrs later. But again, we need to agree on “better”.
It seems that small amounts of animal protein, spread across several intervals leads to larger net MPS gains, per the leucine balance dynamic. It might not matter at all with your singular “beef protein challenge”.