Lifting weights is better than cardio for weight loss

This post is part 2 of my “Shut up your face if you don’t know what the hell you’re talking about” answer to all the dumb things I’ve heard about cardio from people who don’t do cardio.

The high-end, education-focused gym where I used to work was a wonderful place to learn, but a terrible place to work (labor violations, discrimination, and exploiting employees are a matter of routine there), so last summer I started interviewing at other gyms. Since a new lower budget gym was opening up less than a mile from my house, I interviewed for a job as their personal training sales director. It was one of those interviews that went more like an orientation than an actual interview, and the hiring manager spent most of the time explaining their sales pitch than asking questions of me. The pitch went something like this:

Most people who join a gym are joining to lose weight, so they come and use the cardio machines and don’t lose any weight. Do you know how many calories it takes to lose a pound of fat? 3500 calories, that’s 500 calories a day. Do you know how many calories you burn in 30 minutes on the treadmill or elliptical? 200-300 calories. You’re never going to lose any weight with that kind of calorie burn. You would have to do an hour or more on the elliptical every single day to lose a pound a week, and as you get smaller you get to eat less and less and exercise more and more to lose any weight. Do you know what the key is to weight loss? Muscle! Every extra pound of muscle you put on burns about 100 extra calories per day. If you put on an additional 5 pounds of muscle, you can be that friend that gets to eat whatever they want because you’ll be burning an extra 500 calories every day just going through your day without doing any exercise. Now you can’t put on 5 pounds of muscle in just a few weeks, it’ll take awhile. You will need to commit to a year of training (meanwhile, he is scratching down all these numbers on the back of a 1 year contract). But our personal training sessions are only 30 minutes, and in those 30 minutes you will not only burn calories, but you will also build the muscle that you need to burn more calories every day. And that way you don’t have to do any cardio!

Let’s ignore all of the other reasons why this presentation was offensive to my integrity as a fitness professional (and a person with a brain), and just focus on the weights vs. cardio argument. Plenty of other fitness programs use a similar argument to sell their method of fitness: Crossfit, Jillian Michaels videos, and personal trainers the world over - including the high-end gym I worked at. And the argument, like Disney’s Pocahontas, is based on a true story, but not the whole truth.

Energy balance - where those 500 calories come from?

For most people you can burn 500 calories in about 45 minutes of running, an hour of “vigorous” cycling (think, Spin class or a tough group ride), or about an hour and a quarter of intense circuit training. These numbers are estimates and will vary based on your body and fitness level. No matter how you burn those 500 calories, you can eat them right back with one Clif bar, a grande latte, and a rice cake. At my size, the number of calories I burn in a marathon can be eaten right back in one Chipotle burrito. Clearly, you can eat yourself out of any work you do in the gym with a few extra forkfuls of food at every meal. No matter what method of exercise you use, nutrition must be the greater part of your weight loss plan.

If you’re not thoroughly depressed yet, consider cheat days. The idea is that if you behave 6 2/3 days of the week, you can have one cheat meal, or better yet, spread the cheating over the course of the day. So let’s say you’ve been good all week, netting a deficit of 500 calories per day for 6 days. To reward yourself, you go to the Cheesecake Factory and eat:

2 avocado egg roles (2x960 cal)

A chicken caesar salad (980 cal)

A piece of strawberry cheesecake (730 cal)

2 glasses of wine (2x120 calories)

Total: 3870 calories

In one meal, you have not only erased the 3000 calorie deficit that you had accumulated over the course of the week, but you have also added an additional 1000 calories to your tab. At that rate, you can expect to gain a pound every 3.5 weeks. I don’t mean to depress you, but you might as well give up the idea that rich foods are a god-given right. If you want to lose the weight and keep it off, your concept of what food is can no longer include cheescake and fried egg rolls. Tough titties.

Muscle gain… and the role of shitty trainers

It is not all that easy to put on 5lb of muscle (especially if you’re a chick, naturally kind of skinny, or not that good at lifting weights). You have to train consistently, in the correct range of reps and intensity, progressively increasing total load and work done (weight x time under tension), while still incorporating enough rest for your muscles to rebuild. Oh yeah, and you have to be in positive energy balance (meaning eating more calories than you’re burning), so if you don’t want to gain weight while you’re building muscle it will happen even more slowly.

Yeah, bro. That is totally the most
efficient and safe way to do whatever
it is that you're trying to do.

Most trainers, in an attempt to dazzle you with how awesome they are, change up the program too much for the kind of progressive overload you need to efficiently build muscle. It is also difficult for a trainer to land on the correct load that will produce true failure between 8 and 12 (preferably 10) reps. Instead, 10 reps becomes like a contract: you reach 10 and stop before you have reached the level of intensity that will truly build muscle (you have fulfilled your side of the contract), or your trainer picks a weight that is too heavy, you can’t fulfil your end of the contract, and so they pick something that is too light so that you can finish with a feeling of success and easily reach your contractual obligation of 10 reps… and then don’t give your muscles the stimulus they need to grow. And a lot of trainers just aren’t very good and do dumb stuff like train your upper body more than your lower body (training the legs releases the most growth hormone, so even if you want a bigger upper body you will still get better results if you train your lower body as well), train one muscle group more than its opposing group, or let you get away with bad form and use the wrong muscles to do the work. Add to that the fact that most people are not consistent about showing up to their training sessions with their A game 3-4x per week, and the chances of overcoming lifestyle inertia to put on those 5lb of muscle on the same diet is pretty remote.

Remember, too, that in the sales pitch scenario you’re here to burn calories so that you can lose weight. You will build more muscle and burn more calories the harder you work in your weightlifting session, but most people can’t handle the cardiovascular demands of a true circuit session. I learned pretty quickly that the best way for me to end a session early would be to have a guy do a set of body weight squats followed by a set of push-ups in their first month of training. When they stood up to do the second set of squats, their blood pressure would stay low, the blood vessels in their legs would dilate, and then they would get faint and nauseous. Nearly every time, the guy would end up lying on the ground with his feet in the air asking for orange juice so he wouldn’t pass out. So much for trying to sell him personal training...

Even if you are fit enough to handle the blood pressure changes, lactate clearing, and high heart rate demands of a true circuit workout, it’s still hard to match the calorie-burning capacity of a cardio workout of a similar intensity. Let’s say you do an intense circuit of 3 sets of 10 repetitions of 7 exercises. Every set will take you roughly 20s, but every transition between exercises will probably also take about 20s. As you do more and more of these anaerobic exercises back-to-back, your blood lactate level and heart rate will climb, and eventually between sets you will need an extra minute or so of rest to get your heart rate back below your anaerobic threshold (the threshold you simply can’t sustain for more than a few minutes). Even if your trainer is excellent at managing time, you are still probably only working for 15-20 of those 30 minutes and the rest is dedicated to recovery, explaining, demonstrating, collecting equipment, and correcting. Although your heart rate is higher during those 15-20 minutes than it would be if you were running, it's not high enough to compensate for the lost time. In a 30 minute weightlifting session, you’d be lucky to burn more than an underwhelming 250 calories.

This missing link: the role of fitness in exercise weight loss

Let’s go back to the slimy Chain Gym sales guy and dissect his pitch. It is based on the assumption that burning 500 calories is a difficult and onerous task. Speak for yourself, Mr. Meatsweats; I burn 500 calories during one of my recovery workouts, and routinely burn more than 1,000 calories per day every day during marathon training. (Have you ever noticed that every time someone makes the “weights burn more calories” argument they severely underestimate the calorie cost of an hour worth of activity? Like 250lb guys estimating an hour of running at 400 calories?) Burning 500 calories is only an onerous task if you are unfit and suck at it. In order to be able to burn 500 calories per session, you need to start with burning 200 calories per session and slowly build up from there. In short, the ONLY way you can lose weight through exercise is if you make exercise a part of your daily routine and stop thinking of it as an onerous task.

You can totally change your metabolism with those little
things. What are they? Bottle caps? Here, have a cookie.

The same goes for weightlifting, by the way. If you want to put on 5lb of muscle quickly, then you’re going to have to build up the fitness to do the intensity that builds muscle most efficiently. Let’s say that you have to lift 1 million ogblats (a made-up standard of measure, abbreviated &) to put on 5 lb of muscle. If you can lift 500& for 4 sets of 10, 3 times per week it will only take you 4 months to get the work done. However, if you are a novice and can only lift 200&, for 3 sets of 12 repetitions, twice per week it will take you 6 years to do the work it takes to put on 5lb of muscle. Of course, this example is simply meant to illustrate a point, because muscle gain isn’t nearly so linear. Instead, let’s consider a more familiar example from the cardio world: a runner. Let’s take 2 runners that are trying to lose weight: each of whom burns 100 calories per mile. Each needs to run 700 miles and maintain their calorie intake to lose 20lb. However, the runner who can run an hour a day at 7mph can lose 20lb in 14 weeks, while the “jogger” who can only run 40 minutes at 5mph will take more than twice as long (30 weeks, or over 6 months) to burn the same number of calories.

A note about Crossfit (and other circuit training gimmicks): some exercise programs downplay the role of fitness in an exercise program’s effectiveness by claiming that circuit training  - defined as any resistance training with minimal rest - is a shortcut to burning more calories. However, no matter how you scale the workout, a fit person will still burn more calories per session by either lifting a weight for more reps per unit of time, or by lifting more weight for the same number of reps. There's no way around it. If you're not fit, you can't burn that many calories through exercise. So much for burning off that muffin top at the gym.

The take-home

No matter how you slice it, a successful weight loss program has to include a nutrition component. The reason that most people don’t lose weight by cardio training is that they don’t have the fitness to outpace their appetite. However, once you build the fitness for it, resistance training doesn't burn quite as many calories as cardio. The only resistance-based athlete that can compare to the 6,000 daily calorie demands of a Tour de France rider is perhaps a Strongman competitor (who is still eating MORE than his body requires to maintain his muscle mass at 5-7K calories). For mere mortals, it doesn't really matter what you choose, as long as you will be able to enjoy doing it frequently for a long time while you build the fitness to burn a shitton of calories. The best way to burn calories through exercise is to build the fitness to be able to work out hard for an hour, and then focus on your diet.

Next bullshit myth: You can run faster by lifting weights.