So from 2013-2017 or so I ate a lot of food and did strength training. I got a lot stronger and bigger. I did not count my calories. I'll call this point A.
Then I got a DEXA scan, saw that I was 19% body fat and decided to do a slow cut. I set a calorie target (X calories, let's say) and followed it every day while keeping protein intake high. I also added in a lot of cardio to my training and switched more of a "power-building" routine that included both heavy lifting and higher-rep accessory movements. All went well and I got to 10% on my next DEXA after about 6-7 months (mid-2018). The DEXA showed that I gained ~1lb of muscle while losing a lot of fat. I was really happy with how I looked (shredded, 10% on a DEXA is a lot lower than what most people think of as 10%). I kept lifting heavy to try to keep my strength. I was able to maintain my strength on some lifts (deadlifts), improve on others (pullups) but it did go down on the pressing movements. Perhaps mostly out of inertia, I stayed here from 2018-early 2020. I actually got even leaner towards the end of this period but it's not too significant, I think. Let's call this point B.
Then the pandemic happened. I lost access to my gym and, while I did have some equipment at home, it wasn't nearly what I was used to. I kept the same calorie target and kept doing cardio. My lifting routine was more bare-bones and included a lot of weighted pull-ups. I also worked heavily on my form for deadlifts which was in need of improvement but didn't have the weights to really train very heavy. So, while my form did in fact improve a lot, I lost quite a bit of strength. My body composition did not visually change though. My weight stayed the same. Let's call this point C.
Presently, I was able to obtain a lot more weights and equipment for my home gym and gyms are now open more regularly than before. I am able to do heavy training again. However, the problem that I am experiencing is that it is difficult for me to re-gain my strength. In other words, I am having a hard time getting back to point B in terms of strength.
The question is: does it take more calories to re-gain strength previously lost due to lack of heavy training than it does to maintain it? So, whereas X calories may have been enough to maintain most of my strength from point A to point B, is it not enough to get from C back to B? In other words, am I wasting my time trying to increase my strength without increasing my calories, even if I previously did have that same level of strength with X calories.