If you're eating 5 to 6 times a day, eating right and sipping protein, then your body should always be in anabolic state. You'll have plenty of BCAA in you already, digested, predigested, and waiting to be digested. Swallowing another 10g of BCAA powder is redundant. Your body will treat it like it's just another protein.
They said your stomach have to be empty to take in BCAA for full effect. If you're training, you shouldn't be in that state (hungry) in the first place. You don't want to be in a state where you're hungry. When you are hungry, you have to eat right away - not take in 10g of BCAA and then wait for like 30 minutes before you eat. That's too much time to be hungry. Even when you're dieting, BCAA won't help much. If your body is in catabolic state, it'll just burn up the 10g of BCAA you just swallowed and convert it to energy.
I can only think of 2 window of opportunity when your body is depleted with BCAA, that's when you just woke up and after training. How long does it take for whey to digest and enter your system? Less than 30 minutes? Is it critical for you not to wait 30 minutes and you must have the BCAA in you asap? Are you in some kind of super training regiment that you can't afford 30 minutes to digest your whey? If so, are there suppository version of BCAA? You won't add an extra inch on your arms just because BCAA entered your body a few minutes earlier than your training buddy.