What happens when you do strength training but eat a low protein low carb high fat diet? Do you just retain muscle mass or is there a way to add muscle on such a diet?
No. You cannot add muscle without protein. Muscle is made of protein, your body cannot synthesize or store it. Therefore without it your body is incapable of adding muscle. Your body will probably end up breaking down other muscles in order to satisfy its requirement.
If my life depended on you putting on as little muscle as possible and all I could control was your macros, this is exactly what I would make you do. You’ll have no energy for your workouts, glycogen stores will be slow to replenish, muscle protein synthesis will be low.
I encourage you to take a peak into Dr. Dom D’Agstino’ s work. There is a quick YouTube on bodybuilding.com that will provide you with a general background. Strength training can be a broad area - if you are focused on maintaining muscle, ensure you are lifting consistently. If you are focused on gaining muscle then a diet like this is not optimal, but you may not care. It also depends on what you mean by “low” carbs and protein… I assume <80g/day? If building muscle is your goal, you can also check out Joe Klemczewski’s work, Alan Aragon and Brad Schoendfeld.