Significant muscle building takes years rather than months, and the amount of muscular weight increase feasible in a month is actually relatively little. Any significant weight changes over the course of a month are usually the consequence of fluid loss or retention rather than new, bulging muscles. The only exception may be if you are using drugs that have an anabolic effect - for example, steroids. In this case, you might be able to gain some muscle in a single month.
The average man's body weighs about half a ton, and the maximum muscle mass that can be sustained for any length of time without losing water content is close to that figure - around 500-600 grams (about 1-1.3 pounds). If your current weight is 90 kg (198 lbs), then it follows that your maximum muscle mass would be about 4500 g (100 pounds). Most men will not reach this level even after many years of training so it is clear that it takes at least several years to grow big muscles.
In fact, it has been estimated that it takes more than 10,000 hours of practice to become an expert in a skill such as tennis, golf, or boxing, and it also takes at least five years to develop serious strength levels appropriate to these sports. Thus, if we assume that you make enough effort during this period to keep up with the experts, then you should be able to add significant muscle mass to your frame.
With all of these in mind, Jacobchick estimates that the average guy may acquire one to two pounds of muscle every month and the average lady can add up to one pound per month. This means that if you were to maintain this level of activity for a whole year, you would add 24 to 48 pounds of muscle mass.
The truth is that it depends on how much you eat and what kind of exercise you do. So, if you want to know how much weight you can gain in a month, just keep reading.
Here are some more interesting facts about how much weight you can gain in a month:
If you eat more than 20% of your body weight in calories each day, you will likely gain weight. If you only eat 10% of your body weight in calories each day, you won't be able to lose weight even if you try hard enough.
Water weighs more than flesh, so if you drink enough water you can gain more water weight and thus increase your body weight. However, if you don't drink enough water and go without food, you will start losing water through dehydration which will decrease your body weight.
Fat cells store energy - they don't talk back.
"The novice lifter is normally able to acquire between 1 and 4 pounds of muscle in a month," says celebrity PT Scott Laidler. This amounts to a maximum of little more than 1.8 kg of muscle, which is plenty for slim guys to begin showing considerable definition. More experienced athletes may be able to gain up to 5 or 6 pounds in a month, which would bring their monthly total to about 3.5 kg or more. That's enough muscle to make a difference, especially if they are training hard enough to grow.
Here's how much muscle you need to become physically attractive: If you want men to find you physically appealing, then you should aim to build at least three-quarters of an inch of muscle per year. So if your current level of development is half way between being fat and being thin, then you should aim to gain a total of one-and-a-half inches over the next year. Of course, most people are not able to grow that much muscle quickly, so don't worry about being perfect yet. Just focus on making small gains every week until you reach your target amount.
You can measure yourself by standing with your arms down by your side, then measuring from shoulder to shoulder (chest), across your back ( waist), and down the middle of your thigh (thigh). Use a tape measure or ruler. Repeat with other arm to get average size.