Please let me point you to https://leangains.com

It has a ton of info - Martin Berkhan is really first person who popularized 16:8.

One of advises there is that you can have black coffee with some milk, because milk is really low on calories.

Also, from his site again, 10g of BCAA pre and postworkout does not change expression of fasting markers in blood. 10g of BCAA is ~40 calories. Put differently, it is equal to two teaspoons of sugar.

And, to finalize, he recommends 14:10 regime for women.