Weight Gain Myths

(Last Updated On: August 11, 2011)
You can't gain Fat by lifting weights
You can't gain Fat by lifting weights

We’ve seen a lot of threads in our forums about weightlifting and weight gain lately and we thought it might be a good idea for a little common sense talk about weight gain myths.

 First, it is nearly impossible for even a young adult male to add 5 lbs of muscles doing a weight training program like STS for 3 months. The most muscle a male could hope to add to their body doing a weight training workout for 3 months is only about one pound, less for a female. 

Remember, more than half your body’s weight is made up of water. Short term fluctuations in your weight have more to do with increases or decreases in water retention – not muscle and/or fat.

Second, weight gain and weight loss come from three areas of your body:

1. Water – this makes up about 2/3 of your body weight
2. Fat 
3. Muscle

Many times you might notice that you gain 3 to 5 pounds in just one day! Relax it’s not fat and it certainly is not muscle. That only leaves one other choice – water! That’s right; the only way anyone can gain 5 lbs of weight in a short period of time is from water retention. 

Water retention may come from eating a high sodium meal (Chinese food for example) or your monthly cycle. Water retention also comes from glycogen that is stored in your body. At your peak during the day you have about 1 pound of Glycogen in your body. Glycogen holds onto about 3 times its weight in water. As you deplete your glycogen stores your weight will drop as less water will be stored in your muscles. As you replenish your glycogen in your body by eating your water weight will increase. This is a major reason why you are lighter in the morning than in the evening.

Let me give you an example to expand on this. Let’s say on Tuesday you weigh yourself in the morning and your weight is 145 pounds. On Wednesday you weigh yourself in the evening and this time you freak out because you weigh 150 pounds. How could this happen? 

Well, first let’s look at muscle. Even though you did do STS mesocycle three on Tuesday afternoon and lifted some very heavy weights it is impossible to add 5 lbs of muscle to your body in just one day. In fact, it is very hard for a male to add much more than 4 lbs of muscle in a year. So your weight gain wasn’t at all muscle. Well, then it must be fat because the scale says so – right? Well, of course I’m just being funny to make a point. A scale can only tell you how much you weigh, not where the weight came from. To gain 5 pounds of fat in just one day you would have to consume 17500 extra calories more than you normally eat (assuming activity level is the same). This too is impossible as you would have to eat around 32 Big Macs in addition to your normal meals to be able to even come close to adding 5 lbs of fat to your body. Even if a person wanted to they could not eat 32 Big Macs in just one day – It’s just not possible and it is IMPOSSIBLE to gain 5 lb’s of fat in just one day. Stored fat only comes from eating excess food, not exercise. It is impossible to gain fat by lifting weights or breathing air.

So we have eliminated muscle and fat as being the cause of your one day weight gain in the above example. This only leaves “water” as the culprit to your short term weight gain.

Now I will admit that any weightlifting program can cause temporary water weight gain. When you begin any new weightlifting program your body will retain water in the beginning. This is because your body’s muscles will temporarily store more glycogen when you start a new program and this attracts more water to your muscles. This is one reason why your muscles swell. After your body adapts to the new program your body will stop storing excess glycogen and the water retention will decrease.

Finally, scales are not 100% accurate. They have a certain error rate of + or – a certain percentage and may be off as much as several pounds. This may mean that you actually weigh more or less than what the scale tells you. For example, the scale tells you on Monday that you weigh 100 lbs (but your real weight is 102 lbs) and then on Wednesday the scale tells you that you weigh 104 lbs (but your real weight is still 102 lbs). You might think you gained 4 pounds when you actually gained nothing.

7 thoughts on “Weight Gain Myths

  1. So. Cathe this mean that after 3 months I will loose the water I have in my body? If I’m doing STS for 3 months and then after this I’ll do it all over again, I will see better results?


  2. Once your body adapts to a new weightlifting routine it will be less likely to store excess glycogen and this means less excess water will be stored in your body. But we’re only talking about a very small amount of water. The point of the article is to get you to stop worrying about temporary weight fluctuations as they are only the result of water retention. I can’t tell you how many people through the years I’ve heard say they quit or changed a routine because they gained a few pounds not realizing it was only water weight.

    In any weight loss and fitness program you need to think long-term as in months and years, not days. An analogy to this might be a business. In any successful business you will have good days and bad days, but you don’t declare bankruptcy or change your business plan because you had a few bad days. Hopefully, at the end of the year you will have had many more good days than bad ones and made a lot of money. The same is true of any weight loss program. You’re not going to have steady weight loss every day and your weight will likely fluctuate up and down, but over several months the trend should show that you’re losing weight.

    So think long term and stop worrying about weight fluctuations caused by water retention. And always remember that it is impossible to gain fat from lifting weights. Fat comes from the potato chip bag and the dinner plate, not the barbell.

  3. Ms. Cathe, I run quite a bit every week because I hear it helps with concentration and mood elevation. I started over 1 year ago, and my head is still cloudy. Can you tell me what to do and I will turn on every tv to your show. Even if you don’t respond, I will still watch your show and practice.


  4. Okay Cathe I am not athletic in nature but i wish to become physically fit – I am 32 and weigh approximately 120-125 and am 5’3- where do I start when lifting weights? I notice you use different weights when doing over head presses because of your comfort level I don’t think I have a comfort level yet? What do I start with ?I know I can use up to eight to ten on dumbells. Which programs should I order to help me keep up ! I want to work on upper and especially lower but I couldn’t find anything except the intermediate! Would that work if use smaller weights and if so what’s a safe size for barbells.

  5. Cathe, Love your explanation about the water retention and glycogen storage. It really helps to understand the scale fluctation. I only weigh in about once a month (that’s usually depressing enough :)!)

    I also appreciate the “long-term” viewpoint of the business analogy. I am a business person AND work with investment strategies, so I can definitely apply long-term to my workouts as well.

    I’ll never give up anyway-HA!

    (Cosmo Mom)

  6. I run a healthylifestyle club and one of my male members states he has put on weight because he is bulking?
    He states he has not increased his calorie intake although he has increased his gym workout…I am confused.
    I was under the belief that if calorie intake does not match up to energy output then the result would be weight loss regardless of muscle building?

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