The very first few months of training, I ate significantly less than I should have been. I was under the impression that the less calories I consume, the leaner I would become. I would consume a “normal” amount of food (normal for an “average” person, who isn’t looking to put on or lose weight) and still see slow and gradual results. However, I needed significantly more calories to grow as I wanted to, as I had to make up for all the energy I would expend daily, as well as a surplus for my muscles to be able to grow. I attribute seeing results with the low calorie intake to the initial adaptation phase a body goes through when one first begins to lift. In this phase, it is possible and probable to gain muscle as well as loose fat simultaneously. I can only imagine what I would look like today, had I had my nutrition in check from day one.
It got to the point where I was eating as little as possible, aiming for around 1500 calories (when it should have been around 3200, plus whatever exercise I did that day), sometimes getting as low as 800. Some days it was not a problem, some days it was a struggle. This lasted about 2 weeks. I then had one or two mini binges, and knew this was not the way to go. I began spending much time researching bodybuilding nutrition, where I eventually learned what kind of foods to eat and when (according to other people, of course). This set me in the right direction to figuring out for myself what worked the best for me. If asked today, I would highly recommend against drastically lowering calories, especially in a very short time period. Not only is there much science showing the devastating effects this can have on your metabolism and mental health, but in my own experience, it just sucks. I knew I would never do that to myself again.
The other extreme that I have experienced would be transitioning from losing fat to gaining muscle and weight. I have done this about 5 times so far, and have learned that for me, the most effective way is to gradually increase the calories (same goes for bulking to cutting, the lowering of cals should be gradual). I used to increase my intake overnight, for example going from 2400kcals/day on a cut, to deciding I want to bulk and the next day beginning with 3500 kcals. This drastic change made it more difficult for my body to adapt, and I would gain significantly more fat (and water) than now, where I gradually increase (maybe over a period of a week or two, which is still a little too fast for me). The rapid weight/fat gain would make it that much more difficult and take that much longer to remove it and attain the leanness I desired.
The bottom line, based on my experiences, is if you decided to change something, change it gradually. Be forceful about the change, yet delicate in it’s implementation. This will save time and effort in the long run. It’s all about the long run!