Lifting weights is a great form of exercise that can help you tone and strengthen muscles while shedding unwanted fat. Unfortunately, it is sometimes tossed to the wayside by those who fear that pumping iron will cause the numbers on the scale to go up. While some people do indeed gain weight when lifting weights, they generally do so on purpose. There are many factors that go into weight gain via strength training that the average person doesn't need to worry about.
Weight vs Size
The first thing to consider when concerned with weight gain is what matters more -- the numbers on the scale or the number on the tag inside your jeans. While weightlifting may not necessarily make you gain weight, it may keep the numbers on the scale from dropping like you would like them to. The reason this happens is because muscle weighs more than fat but it also takes up less space. So one pound of lean muscle will look a lot more appealing on your body than one pound of bulky fat. After lifting for a few weeks, you'll likely be disappointed to find that the scale still reads the same but delighted to find that you can now button and zip your old skinny jeans. Lifting weights may not help you lose weight but will definitely help you lose inches.
There's no doubt about it -- if you want to gain weight while lifting weights you can, but it's going to take a lot of nutritional discipline. In order for lifting weights to make you gain weight, you have to increase your caloric intake. The American College of Sports Medicine (ACSM) recommends that you aim for an additional 400 to 500 calories per day in order to gain weight. If you fail to meet that quota then chances are your weight will not increase. Be sure not to fall into the trap of thinking you can eat more because you did a weight workout; this will almost always result in weight gain. Your appetite may increase from the extra activity, but be smart about what and how much you put in your mouth. It's easy to over indulge, gain weight and then blame your workout.
Protein is a very important component of building muscle tissue and potentially gaining weight. But do not avoid protein for fear of gaining weight because it is essential for every aspect of your body, not just muscle. Most people require only 0.8 grams of protein per kilogram of body weight per day, but the ACSM advises that athletes and those aiming for weight gain get as much as 1.7 grams per kilogram of body weight per day. If you are lifting weights on a regular basis, it's a good idea to up your protein intake a bit to accommodate your working muscles and speed up recovery. It can also help encourage muscle growth without making you gain weight or develop bulky muscles. Keep in mind that those who are actively trying to gain weight increase their protein intake considerably.
While calories and protein go a long way in promoting weight gain, in order to gain the desired muscle weight you have to lift weights -- a lot. Performing two to three sets of eight to 12 repetitions of several different exercises using moderate to heavy weights three days a week will likely not have much of an effect on the chances of you gaining weight. In fact, the National Strength and Conditioning Association suggests that in order for muscle growth to occur, you should perform three to six sets of six to 12 repetitions using heavier weights three to seven days per week. And to really build muscle, you should perform at least three different exercises for each muscle group. That would add up to a very long time spent in the gym everyday, and even then weight gain is not guaranteed.
- ACSM's Resource Manual for Guidelines for Exercise Testing and Prescription, Fifth Edition; Leonard A. Kaminsky, PhD, FACSM, et al
- Essentials of Strength Training and Conditioning, Third Edition; Thomas R. Baechle, EdD, et al
Jen Weir writes for several websites, specializing in the health and fitness field. She holds a Bachelor of Science in exercise science from Montana State University, is an NSCA-certified strength and conditioning specialist and maintains a personal trainer certification from the American College of Sports Medicine.