Stronger for the Long Haul: How Strength Training Helps You Keep the Weight Off
When most people begin a weight loss program, they do so with the intention of keeping that weight off for as long as possible. I don’t think I’ve ever heard of someone saying they want to shed 40 pounds, but just for a few months. People exercise and diet with the intention of changing their life long term, whether that be for health or aesthetic reasons. Unfortunately, our bodies don’t like it when we lose weight. We have to fight an uphill battle when it comes to both losing weight and keeping that weight off for good. This is only exacerbated by the way most people go about dieting and exercise, so, before you buy a pair of running shoes and stock up on salads for lunch, let's take a look into how our bodies respond to weight loss.
The ever adaptable human metabolism seems to have a bit of an odd place in today’s food-rich and calorie-dense modern society. Our evolutionary development has primed us to survive against starvation out in the wild, but, when it comes to weight loss, we voluntarily impart starvation upon ourselves to shed extra pounds of unwanted fat. We limit our incoming calories by dieting, and we workout to increase our calories burned. This is no different than entering a real starvation state as far as our bodies are concerned.
Back when we were all cavemen hunting mammoths and picking berries, meals were hard to come by and we often went days or weeks without a steady source of food. Our bodies evolved in these food scarce conditions for most of our existence as a species. It's only been for a short span of our history that we humans have been settled down as farmers and herders to have a steady source of food each day. As a result of this, we’ve gotten quite good at surviving with low amounts of food. Our evolution made sure of that for the continuation of our species.
When we begin a weight loss program, and ultimately start losing weight, our bodies begin to adapt to prevent us from losing calorie stores (fat and glycogen) that could mean the difference between survival and death in the wild. These biological adjustments are termed “metabolic adaptations” and were once quite useful to us many thousands of years ago.
Metabolic adaptations can occur as you lose weight and enter a calorie deficit- a net negative amount of calories consumed vs. burned each day. Your body adjusts your metabolism to be more conservative and resistant against burning calories when it doesn’t need to. So as you lose weight, the amount of calories you burn each day will actually decrease! At 200lb, you will burn a higher amount of calories at rest than a 150lb version of you would. Let's analyze why.
Did you know that physical exercise only accounts for about 5-10% of the total amount of calories you burn in a day? That’s right, a 30 minute 200 calorie run really only is a small chip in your total calorie expenditure for the day. This is a big reason why exercise is considered a poor way to lose weight, but that is an article for another day.
A much more significant 60-70% of your daily calorie expenditure is classified as your Basal Metabolic Rate, or BMR. Think of this as the energy your body needs to perform its biological functions- everything from cell division to heartbeats. Changes to BMR affect a much larger portion of your daily calorie expenditure than other things do, and that is where metabolic adaptation hits you hard. The details of what metabolic adaptations alter in your physiology are beyond the scope of this article, but for now, just know that your body becomes more efficient at using its calories in biological processes in order to save energy. In addition to these changes to BMR, studies also show that hunger-stimulating hormones tend to increase with weight loss, as your body attempts to get you to replace lost calories by eating(3). So weight loss is a bit of a double edged sword, you lose weight to get more fit and healthier, but it also gets harder and harder to keep the weight off due to metabolic adaptation. This is why most people who lose a significant amount of weight end up regaining it back in the years following. Estimates show that 90% of people who underwent weight loss ended up regaining most of their weight back within 5 years (3). Even then, the average amount of weight loss maintained after 5 years was only 3% (~3kg) of body weight for standard low calorie diet interventions (1). Worse yet, these changes are fairly permanent and have been shown to persist for years after weight loss (2).
Are we doomed to forever be in a vicious cycle of weight loss, gain, and metabolic adaptations? Thankfully, there are ways to fight back! And this is where we tackle the other side of the topic: how exercise plays a role in combating metabolic adaptation and weight loss.
Here in the US, it’s quite common for people who want to lose weight to grab a gym membership or a pair of running shoes and jump right into some form of cardio exercise. They’ll hop on a treadmill, start walking around their neighborhood or go for runs. The smart watch and the modern treadmill have both deeply reinforced these mediums of exercise for the average person. When expending calories is your main goal, having a big display in your face showing you how many calories you’ve burned is a great motivator for people. They take pride in it. There is a sense of accomplishment seeing 200, 300, or more calories on your treadmill at the end of a long run. But unfortunately most people don’t understand why these modes of exercise are perhaps some of the least efficient ways to lose weight and, more importantly, keep it off.
Now, I am not bashing running or treadmill workouts. Burning 300 calories is burning 300 calories at the end of the day, and, by and large, low intensity steady state (LISS) cardio exercise, like running, out performs strength training when it comes to raw calories burned per minute. Additionally, the cardiovascular health benefits that LISS exercise provides are extremely important to one’s overall health and should not be overlooked. Running and cardio is good for you- it's just not good at keeping fat off.
As we previously discussed, exercise-based physical activity makes up a very small portion of your daily calorie expenditure. Do we really want to spend time, energy, and money every single day going to the gym and sweating over a long workout just to move the energy balance scale 5% in our favor? Likely not. There is a common saying I give to my clients, “You can’t outrun a bad diet”. As a gym owner, stating this so explicitly seems like career suicide; why go to a gym when you just said how little exercise matters for losing weight? Yes, losing weight is heavily a result of your diet, but keeping weight off and keeping yourself minimally impacted by metabolic adaptations is where strength training shines. Let’s analyze how.
Muscle tissue is some of the most energy inefficient tissue in our body. From a weight loss perspective, that's a good thing! This means that the more muscle we have, the more calories we burn at rest. Our BMR goes up as our body uses more energy to maintain the muscle mass it has. If metabolic adaptation lowers BMR as we lose weight, and adding muscle mass increases BMR, it only makes sense to supplement weight loss with strength training to minimize the effects that metabolic adaptation has on our body. Strength training is the best line of defense against the issue of metabolic adaptation.
Indeed, strength training usually does not burn as many calories per minute as LISS cardio exercise does, but that actually might be a good thing when it comes to staving off metabolic adaptation. Usually, metabolic adaptation effects increase with the intensity of weight loss. Faster and more extreme amounts of weight loss will incur more severe effects of metabolic adaptation. For this reason, we want to obtain a slow, steady weight loss that replaces lost fat mass with muscle mass. LISS cardio is quite energy demanding and will shred calories, but too much of a calorie deficit too quickly is a recipe for your metabolism tanking.
Additionally, we should be aware of the fact that, with any weight loss, you will be expected to lose some degree of muscle as well. It's quite difficult to build muscle while being in a caloric deficit. This is another common reason people struggle to keep weight off for long periods of time. They end up losing a portion of their muscle mass during dieting and do nothing to replace it. The best thing to combat said muscle loss is, you guessed it, strength training. Stimulating muscles and eating high amounts of protein in your diet can alleviate this problem significantly. If you are simply running and dieting, you risk a double whammy of problems- shedding too many calories too quickly and doing nothing to replace all that lost muscle. Besides, maintaining muscle will, in theory, make your weight loss easier as you now have your BMR maintained for longer.
This is another more practical reason why strength training and gaining muscle is better for weight loss- it does the work for you. It would be amazing to not have to workout as much or diet as hard to lose weight, right? Well, by increasing your muscle mass and adding all this calorie-hungry tissue to your body, you now have to work less to lose fat! That means less restrictive diets and less time spent at the gym to achieve the same amount of calories burned in a day.
When clients ask me about weight loss I simply tell them this: eat your protein, diet however much you want, and strength train often. Most importantly, you must do something sustainable for you. The best weight loss plan is one that you can adhere to for a long time. Be smart about losing weight and aim to shed just a pound to 1.5 lbs a week. Find a diet that is easy for you to adhere to, and try to replace as much of the empty carbs in your diet with protein. Aside from strength training, you can run and do cardio if you like, but don’t go overboard with it. Make getting stronger your first and top priority, and you’ll keep that fat off for a lot longer.
References
Anderson, J. W., Konz, E. C., Frederich, R. C., & Wood, C. L. (2001). Long-term weight-loss maintenance: a meta-analysis of US studies. The American Journal of Clinical Nutrition, 74(5), 579–584. https://doi.org/10.1093/ajcn/74.5.579
Fothergill, E., Guo, J., Howard, L., Kerns, J. C., Knuth, N. D., Brychta, R., Chen, K. Y., Skarulis, M. C., Walter, M., Walter, P. J., & Hall, K. D. (2016). Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity (Silver Spring, Md.), 24(8), 1612–1619. https://doi.org/10.1002/oby.21538
Rosenbaum, M., & Leibel, R. L. (2010). Adaptive thermogenesis in humans. International Journal of Obesity, 34(S1), S47–S55. https://doi.org/10.1038/ijo.2010.184
Sal Di Stefano. (2021). The Resistance Training Revolution. Hachette UK.
