Ep 29: Science Says - Diet (Calorie Deficit) vs. Exercise (Cardio) for Fat Loss
This is another "Science Says" episode, where we break down a single recent article relevant to the fitness (lifting, nutrition, health) industry and strategies you can apply right away based on what the science says.
Today's article is "Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men. A randomized, controlled trial." by Ross, et al. (2000).
The main question is, which is better for weight loss: diet (a calorie deficit) or exercise (in the form of cardio)? Listen to find out—you might be surprised!
RELATED LINKS
Ross, R., Dagnone, D., Jones, P. J., Smith, H., Paddags, A., Hudson, R., & Janssen, I. (2000). Reduction in obesity and related comorbid conditions after diet-induced weight loss or exercise-induced weight loss in men. A randomized, controlled trial. Annals of internal medicine, 133(2), 92–103.
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Transcript
Philip Pape 00:08
Welcome to the Wits & Weights podcast, where we discuss getting strong and healthy with strength training and sustainable nutrition. I'm your host, Philip Pape. And in each episode, we examine strategies to help you achieve physical self mastery through a healthy skepticism of the fitness industry, and a commitment to consistent nutrition and training for sustainable results. Welcome to another episode of Wits & Weights. Today's our second special episode of Science says,
Philip Pape 00:39
where I review a research article talking about the findings and how you can apply it in your life to improve your overall health and fitness. The study we're talking about today is titled reduction in obesity and related co morbid conditions after diet induced weight loss or exercise induced weight loss in men, a randomized control trial. This is from 2000 by Ross at all. And it is a fine example of a study on the topic comparing dieting with cardio, and he participants in the study included males who were overweight and or obese. So that was a BMI above 27, a waist above 39 inches. And they've had, they've maintained their weight for six months before the study began. Out of the four groups. In this study, two of the groups were assigned to lose body fat. One group was the diet only group. And one group was the cardio only group for both groups. They put them through a four to five week period, where they basically got them to maintenance. And they confirmed this using doubly labeled water measurements, which is very highly precise way of calculating the expenditure. And then during the study, the participants had to go to seminars every week with a dietitian, where they were taught about food selection and preparing food. And then they had to keep logs of their food. So the researchers understood their intake. Now the duration of the study was 20 weeks, of which 12 weeks were for the weight loss phase. And during those 12 weeks the diet only group they cut their calories by 700 calories per day. So they were in a deficit of 700 per day, and they didn't do any cardio. Conversely, the cardio only group were at maintenance, but they expended 700 calories a day using cardio without dieting. So it's a very clear control of the specific variable of interest here, which is whether dieting 700 calories a day, or cardio 700 calories a day, which one was more effective. And then as far as the macros in their diet, it's more percentage based because obviously the dieting group is going to be on fewer calories, but the percentages were 55 to 60% carbs, 15 to 20% protein 20 to 25% fat. Now if we look at the cardio only group, we talk about what kind of cardio they did, they basically did brisk walking or light jogging. So I would call that low intensity steady state generally. And they did this long enough so that they could burn 700 calories, which resulted in an average time of an hour per day at just below 80% max heart rate. So the end result because of how well this was controlled, monitored, measured, was that both groups had an effective deficit of 700 calories per day. One was purely from cardio, and one was purely from diet. And by the way, I want to go off on a little tangent here, because one thing that struck me when I was reading about the exercise, that they're brisk, briskly walking for about an hour a day, and I'm always talking about the value of steps of walking, especially with my clients of if we can just walk an extra two, four, maybe 6000 steps a day, you know, oftentimes, people are getting 4000, because they have a desk job and they're not moving around a lot. And then they go up to 8000. Well, that that for that extra 4000 steps, is probably about 4550 minutes of walking, just normal walking. And of course, it'd be slightly less if you were briskly walking, which if you can tell from this study, if you're able to add 700 calories, your expenditure for one hour, then you're going to still add four or 500 calories to expenditure from adding about 4000 steps. So I think just without even going any further in the study, this is good evidence that you know, without down regulating your metabolism by doing the higher intensity forms of cardio that I typically warn against overdoing because of the recovery and the metabolic effects. And this low intensity version of cardio can actually be quite highly effective for helping with your metabolism, but we're gonna get They're later in the study when we talk about the results, and what combination of this kind of cardio and diet we might want to incorporate for the best outcome. So now I want to talk about what they measured. And it would be the things you would expect, they measured, the resting, the RMR, it's called which some people use interchangeably with BMR. But it's a component of your metabolism. They measured body weight, they measure body fat, and then they used an MRI machine to measure muscle mass. So they had some fancy tools at their disposal. So now let's talk about the results. So after the 12 weeks, both groups lost the same percentage of weight, they both lost about 16 pounds, 16 pounds for the diet group, 17 pounds for the cardio only group. So those are basically exactly the same. But the big difference was actually in the change in body composition. Something we talked about a lot in this podcast is the value of improving your body composition, cutting fat, and maintaining muscle or building muscle while not adding too much fat.
Philip Pape 06:06
Hey, this is Philip pape, letting you know that applications are now open for one on one coaching. If you're a busy working professional, who has tried dieting, and exercising for years, with little in the way of results, and you want to lose fat, get lean or feel confident in your body without excessive dieting, cardio or restrictions just go to wits & weights.com/coaching, to apply.
Philip Pape 06:30
So in this study, the group doing just cardio actually lost a lot more body fat 4.3% than the diet only group 3.4%. In statistical terms, that's a lot. It's only about 1% difference, they still both loss, decent amount of weight and body fat. But in addition to that, so Compounding this, the group that did the cardio lost less muscle 2.2 pounds, then the cardio only group which lost 4.8 pounds of muscle. So when you use a ratio, the group that was relying on the diet calorie deficit, they lost 70% from fat 30% from muscle, the cardio group lost 85% of their weight from fat and 15%. From muscle. This is a fairly profound outcome showing that when you combine the two, the cardio only group, despite losing the same amount of weight actually lost more of that weight as fat. Now here's another interesting finding. Both groups saw that there saw their resting metabolic rate decrease, but the diet only group their rate decreased by 40%. More than the cardio only group. So the fact that they were in a diet in a deficit caused their metabolism, their metabolic rate to decline more precipitously than the cardio only group. And this is actually consistent with the fact that the cardio only group retained more muscle, because muscle is more expensive. And we talk about the fact that having more muscle mass actually keeps your metabolic rate higher, and that the fat free mass or your body composition is the biggest impact when it comes to your metabolic rate. Other than the short term fluctuations like meat like steps, like activity. Now there's one huge caveat to this study. And that is the participants in the study, were not resistance trained, which is something we all tried to do the listeners of this podcast, we know the value of strength training of resistance training as part of your daily regimen, or maybe not daily, but as part of your ongoing consistent weekly regimen, you strength train. And people tend to make the argument However, and this study counters that, that somehow dieting is the best thing you can do for fat loss and that cardio is somehow ineffective. And I don't I've never said that. I always say that. You don't want to do too much medium intensity cardio, so it doesn't interfere with your lifting and your recovery. But I also say at the same time that cardio was an excellent boost for fat loss during the diet said that many times that you can use HIIT sessions or low intensity cardio or definitely walking in steps to give you a boost your metabolic rate. So now the question is, should we be in a calorie deficit to lose fat and weight? Or should we only try to get it from activity? And I think you know, the answer is I think, you know, the answer is actually both because we never want to rely on on strictly having to move a certain amount every day just to lose weight. And furthermore, it's usually not enough when we're trying to get into a certain deficit and lose at a certain rate of loss. So at the end of the day, what we're saying is the takeaway from this is the best way to optimize fat loss is to use a calorie deficit combined with some cardio in your program, and that cardio could be simply walking and that is why I always recommend and with my clients, we go through a metabolic restoration or preparation phase for probably two to as many as eight weeks before we go into a fat loss phase, and during that initial phase, we start upping our steps, we incorporate training, we incorporate sufficient protein, and then manage the stressors, the sleep, distress, and so on. So that puts us into a great position metabolically to start that fat loss phase. And that we have the habits in place like the steps to keep the metabolism high enough, so we can diet on higher calories. And so that when we hit the gas pedal on the fat loss phase, we then can go into a deficit, but it's not as painful, we're not at such low calories, we're using our steps to supplement our diet, because we've already started to increase our steps. And thus, we have an easier time dieting. Now as you get further into a diet, you've experienced some more metabolic adaptation, and you're trying to hold on to muscle mass. This is where adding a little extra cardio in the form of brisk walking, I'm not a big fan of too much running, but I do like sprints, or biking especially because of the biking is fully concentric motion and it doesn't place the any stress on your joints like running does. But either way you can do what I would say two, maybe three high intensity interval training sessions a week for about 10 to 20 minutes. And a very simple way to do this is interval training, where you go all out for maybe 15 or 30 seconds, and then you rest for two to four times that amount to get fully recovered. So that you can go all out again. And this will allow you to get a little bit of calorie burn in there. Also a little cardio, but it's not so much that you're going to send your body the endurance signal that down regulates your metabolism, and not so much that you're going to recover or interfere with your recovery or with your lifting. And then he tried to do this at least two hours separated from your lifting sessions, and ideally on off days. Another consideration I would have is your hunger. As you get deeper into a diet, if you start to experience the the signs of hunger because of the metabolic adaptation. This is where you might look for other ways to increase your metabolic burn your metabolic rate, so that you can actually eat on more calories. And that's where additional steps can come into play. Or if you're already kind of maxing out your steps, if you're up in the maybe 12 14,000 Step range, and you want some variety wants to do something different. This is where again, a little bit of these other modes of cardio can come into play. So cardio, I'm just going to repeat, if you are doing low intensity, then you could really do quite a bit of that during the week, maybe three times maybe four times, half an hour, if you're doing and when I say low, intense, I mean really low intensity like walking, brisk walking, biking. And that was the inner interval training was what I talked about before, on off days, maybe 20 minutes with the all out and then two to three, two to 4x ratio of rest to all out. Now one other thing I would definitely not take away from this study, I would not take away the thought that you can do cardio instead of strength training. Again, the the participants in the study weren't even resistant strain, but strength training is going to come before anything else. Okay, that is the thing that sends the signal to hold on to muscle mass when you are losing weight period that and then combined with the proper nutrition, which includes a fairly high level of protein, or higher than most people were used to but roughly around a gram per pound of your target body weight. And then steps come into play after that. And then cardio after that. So I hope you found this study useful. I will include the link to the study in the show notes if you want to read it in great detail. And at the end of the day, the thing that works best is what works best for you as an individual. Thanks as always for listening.
Philip Pape 13:52
I wish you the best and stay strong. Thanks for listening to the show. Before you go, I have a quick favor to ask. If you enjoy the podcast. Let me know by leaving a five star review in Apple podcasts and telling others about the show. Thanks again for joining me Philip Pape in this episode of Wits & Weights. I'll see you next time and stay strong.
