Protein needs have an upper and lower boundary, the upper being whatâ€™s the maximum amount of protein synthesis you can sustain in a day, and the lower driven by the bodies protein turnover rate. The body continually breaks down damaged protein structures and rebuilds them, not just in muscles after workouts but in internal organs as well. You have muscle protein breakdown (MPB) competing with muscle protein synthesis (MPS) with your goal being MPS-MPB>=0. Obviously repairing damaged protein in vital organs is higher on the bodies priority list than maintaining that sweet biceps peak you worked so hard for, so if you arenâ€™t taking in the minimum amount of protein youâ€™ll lose muscle mass, and of course strength. The impacts would be subtle, but over enough time noticeable.
Similar to you, Iâ€™m 5â€™8â€ťish and Iâ€™ve been in the weight loss portion of my schedule and have dropped around 8lbs from around 164 to around 156 while seeing my power on the bike go up and run speeds increase, making sure I am getting around 0.8g/lb (1.76g/Kg) day. Iâ€™ve attached a link to a study that used cyclist and triathletes training about 11 hours a week to determine protein needs. There is a lot of debate over the minimum amounts needed, with the most reputable numbers coming in at the 0.6-0.8g/lb a day, and this study found about 0.8g/lb/day required to maintain nitrogen balance. https://www.ncbi.nlm.nih.gov/pubmed/24476478
I would agree AKCrafty that 1970 seems a bit high for basal metabolic rate for 164lbs. I didnâ€™t see your age mentioned but using 40 I get in the 1680-1700 range, 30 jumps that some but only about 60-70 calories. Assuming you get 0.8g/lb of protein each day that will be about 520 calories. I would add about 150 grams of carbs as a starting point (the brain needs 600 calories each day and this must come from carbs or ketones, so unless you are ketogenic this is a good baseline number) which takes you to 1120 calories, then fill the rest with fat up to your desired deficit without the workouts included. Try to make sure you are getting around .3g/lb day of fat though, around 50g/day otherwise over time hormonal issues can develop. Literature on fat intake isnâ€™t as easy to come by as protein but Iâ€™ve also included some info on that.
If you add roughly 50% of your workout calories on top as carbs this should get you pretty close to being carb neutral and providing a decent deficit for fat loss. You can obviously experiment with the carbs and fat calories to get the rate of weight loss you want but this should be a good starting point with a decent guard against muscle loss and hormonal issues that come from too little fat or protein.
As for your actual question of supplementing, whole foods are always preferable, but there are times where I am too lazy or not hungry enough to want to deal with preparing actual food, and in those cases I will use whey powder as supplement. Whey has a very good AA profile but there are some who have a inflammation response to dairy so be conscious of that. We have a stick blender so Iâ€™ll throw in a scoop and just enough water to mix it up and then blend it and down the hatch. The whole process take about 2 minutes and it isnâ€™t enough volume to be a concern if youâ€™re not in the mood to eat.
Hope this helpsâ€¦ http://www.usfsa.org/...nt/Fat_How%20Low.pdf http://www.alanaragonblog.com/...ma-Leigh-Synnott.pdf