Exercise and Weight Loss, Part 2: Strength Training


Strength Training and Weight Loss

by Devin Sarno, NSCA-CPT

As stated in the previous article, Exercise and Weight Loss Part 1, there are a number of different modes of exercise and just about all forms can contribute to weight loss in some way. Yesterday, we discussed aerobic/cardiovascular training and its relationship to weight loss but in this article we are going to focus on traditional strength training, bodybuilding, and how it can impact weight loss to determine if it is an effective choice for losing weight.

Most people hear bodybuilding and immediately think of Arnold Schwarzenegger. While he is the king of the sport of bodybuilding, you do not have to compete to use bodybuilding as your fitness mode of choice. Bodybuilding by definition, is the use of progressive resistance exercise to control and develop one’s musculature. Generally, this is going to be achieved with a split routine of sorts so that you can isolate each muscle group. Some people may even do a different muscle group each day they workout while others may couple together opposing muscle groups or even synergistic muscle groups. Either way, it involves specific muscle targeting in order to build and grow each muscle group in size and strength.
But now you might be asking, if my muscles are getting bigger and stronger, how is that going to help me lose weight? While you will add muscle mass if you are bodybuilding, you will also burn fat at a higher rate and still be contributing to your overall calorie expenditure; in turn making it easier to eat at a deficit. You put on WEIGHT by eating and you gain MUSCLE by lifting. Putting on muscle does not automatically mean you will be putting on weight. If weight loss is your goal, you will most likely be on a calorie restricted diet and if you aren't, you should consider it! I am not talking about limiting yourself to 1,000 calories of fruits and veggies each day and nothing else, I am talking about eating a wholesome, sustainable diet within the limits of the calories that you are burning on a daily basis. If the goal is to put on weight while while bodybuilding, you NEED to eat at a surplus and consume more calories than you burn. So do not confuse the addition of muscle mass with the addition of overall body weight because they are very different.

Bodybuilding and strength training benefits your body even after your workout. Compared to aerobic training where you primarily burn calories during your exercise, weight training can allow for you to burn extra calories for an additional 24-36 hours after your workout. While you won’t be burning the same amount of calories while actually working, it is still a significant amount. This is caused by a physiological affect called Excess Post-Exercise Oxygen Consumption, also referred to as EPOC. This effect is produced when your body is trying to return to homeostasis following exercise, it requires a certain amount of oxygen to return to this state. 

Since bodybuilding and strength training are almost entirely anaerobic, your body will resort to using stored ATP (Adenosine triphosphate) for energy that is not reliant on oxygen, rather than aerobic exercise where you are almost constantly using ATP produced by the oxygen you are taking in. During anaerobic exercise, you will run out of stored ATP much quicker because it cannot be restored during your activity. This is why you reach high levels of fatigue much quicker during anaerobic exercise, meaning the need for oxygen following a primarily anaerobic workout is much greater; you need to reproduce ATP to replace the stored ATP you exhausted, muscle glycogen needs to be resynthesized, blood oxygen levels need to be restored, and muscle tissue needs repairing, all requiring energy, burning calories, to do so.

Beyond the effect of EPOC, having a higher percentage of muscle mass is also helpful for burning calories. When you have more muscle mass, it requires more maintenance and more calories for the maintenance of that muscle. The extra calories your body needs is indicative of a higher resting metabolic rate. Your resting metabolic rate is the amount of calories you burn throughout the day if you did absolutely nothing but breathe. Taking no other calories burnt into account, your body will consume that many calories in an effort to maintain your current state. So the reason that your resting metabolic rate is higher when you have more muscle mass is because muscle mass takes more calories to maintain than fat mass. Bodybuilding will help you increase your lean muscle mass resulting in an increased resting metabolic rate and more calories burned on a daily basis.

Strength training certainly has its upsides when it comes to weight loss when you consider EPOC and the additional muscle mass increasing your resting metabolic rate, but there are some areas where it falls short. During your actual workout session, you will have to spend more time working out to burn the same amount of calories as you would doing other forms of exercise such as cardiovascular exercise. Generally speaking, bodybuilding will not elevate the heart rate by much but when it does, it is for a brief moment. This is why you don’t burn as many immediate calories. Bodybuilding can also cause a phenomenon known as delayed onset muscle soreness (DOMS) unlike cardiovascular exercise, potentially discouraging some individuals from partaking in strength training. Another potential downside to strength training is that since muscle mass does demand more calories for maintenance, it can in some cases actually cause one to overeat to feed their muscle mass.

Strength training is a great way to get stronger and add muscle mass but can also be a great weight loss tool, even with its potential limitations. Given the EPOC principle and the fact that increased muscle mass causes you to burn more calories, strength training may be something you want to consider including in your weight loss journey. But be mindful of how you train to avoid muscle soreness and overeating! Check back next weekend as we dive into two more exercise modes to consider implementing in your weight loss journey.