So this is a common topic and confusion in many people, and I'm going to do the best that I can to explain this situation.
I'm not sure where to start this other than carbs are demonized, and protein is seen as the end all be all with muscle. Everything must be done in it's right time and understood or you will just be spinning your wheels for years. We aren't going to debate about how much protein that we actually need today because then we could be debating all day. That's not the point of this, but to help others recognize that just having a super duper high protein diet, and no carbs is not going to benefit them in the muscle gains that they want.
We all know that protein is a factor that helps us to build lean muscle mass and keep the muscle mass that we have. However, how much is too much? There are certain guidelines and recommendations that you hear for how much protein that you need. You'll hear the bodybuilding community tell you that you need 1g of protein/lb. This was passed down from the fact that these MASSIVE men needed more protein for their muscle mass, when in reality the literature does NOT support that amount of protein for the general population whether for gaining muscle or maintaining muscle.
The typical guideline recommended amount is 0.8g/kg. Do you know how little that is? It's like nothing for what most people would be used to being told for how much protein that they need. But like I said, I'm not hear to talk about whether we need 50g or 150g of protein and which one of these guidelines or where in the middle this falls but the role of protein and carbs on your amount of muscle mass and how to achieve the goals that you are after.
The typical scenario with me as a coach of mostly women is women coming to me eating 150g of protein and super low carbs, and when I give them their macros that are the complete opposite of this, they kinda freak. THIS CAN'T WORK FOR MY GOALS!!! "I want to lose fat and gain muscle."
Is that even possible and is that really even what they want?
First, I'm convinced that all of them even though they do want weight loss just want stability with food. Psychology is HUGE in dieting, and I'm not sure there are many people that actually WANT and desire to eat 150g protein. It's always forcing it down leading to sugar binges in the future, so then it was purposeless to begin with. We always like to ignore the psych factor, but it's SO so huge. The only way you can "make this a lifestyle" is if you actually can live your lifestyle within the parameters of your diet and that just simply isn't sustainable. If you have at least 1.2mg/kg body weight of protein then you are pushing the upper limits of what you need for maintaining or gaining muscle mass.
Does that mean that you shouldn't go higher?
No. That's not what I'm saying. Typically, I will make protein a little higher than what the calculation might be just simply to supplement calories. If I was to give girls macros of 50g protein and 250g carb, they would never want to work with me and most likely their bodies wouldn't respond really well. The studies are only as good as what we have on paper, but when we get into real life, you have to take these things into consideration and the numbers and calculations sometimes have to be thrown out of the window.
Typically if they say they want to lose fat and gain muscle, they really don't want to gain muscle but rather they want a lean toned physique which probably wouldn't even take muscle gains, but rather just leaning them out with the muscle mass that they currently have. We all have a base of muscle right this second, and I think that most women just simply want to see what they are working with, so they go the high protein, low carb approach but the problem is...they never come out of this.
They might cut to a point that they are moderately satisfied because it's depressing but almost always girls are never satisfied (uh) but then they want more results. You can't stay with high protein and lower carb and expect to ACTUALLY gain quality muscle tissue gains. You have to have calories in order to do that. The very first time that you pick up weight lifting and high protein dieting, yes you are going to gain muscle and lose fat at the same time, but after that it's a lot harder.
If you want muscle gains, you are going to have to accept a surplus of calories and some fat gains as well because it's just simply part of the bargain, but that's not ACTUALLY what girls want. They want to stay lean as a bean with abs all while increasing muscle mass. The reality is that it's not that easy. You can do a lean gain type system in a reverse dieting fashion and that's probably the easiest and most effective way to stay lean while increasing muscle mass.
The question that I want you to ask yourself though is what are your TRUE goals. Like are you GENUINELY interested in gaining muscle because if so then you have to deal with fat gains and then lean back out later. If you simply just want to be toned, then most likely you just want to lean out where you are.
The internet is so misleading ESPECIALLY with girls. They see all these high profile bodybuilding girls that are so lean and so muscular, and they just don't look at the big picture. I had a really muscular base from being an athlete my entire life. When I leaned down for the very first time, I had a CRAZY amount of muscle underneath. I also was lifting for the first time. Brittany Dawn for example, did not. She has had to have a couple of cycles of strict strict dieting, then reverse dieting, the strict dieting again then reverse dieting again and now she's landed where she is. Em Dunc is the same way, and I use these girls for examples because I know that they have physiques that everyone would die for but they've done many cycles.
Also almost every single person that you see has done some form of extreme dieting at some point or another, and all of that matters in the long term. I've heard of some of these girls eating as little as 20g C per day (I'm sure their fat and protein was super high as well) during some of their phases of leaning out and then they build back through reverse dieting. You see that at the other end of their reverse diet where they talk about how free they are and forget about the journey.
Do you genuinely want to do that? I mean obviously we all know that it's unhealthy. Do you genuinely think that you could even do that? Would your life situation allow that? Would your psych and relationship with food allow that or would you just end up binge eating? I don't say this in an accusing tone, but just that these are questions that you have to ask yourself when you decide which route that you want to take.
The route that I take with most of my girls is SUSTAINABILITY and longevity in life. I want them to be HAPPY. I want them thriving in their athletic endeavors. I'm not in the business of getting my girls to be the leanest ever, although sometimes that does happen. If they are able to do it realistically with a sound mind and heart, then yea we can continue to do that, but otherwise, it just doesn't make sense and the primary goal that I try to reach is just being able to be happy in your life and food.
I hope this helps clear up some of this, and it's hard to explain so I hope that my points came across well.