There’s a lot of conflicting advice out there when it comes to exercise and fat loss.
You have the people who promote the idea that doing cardio and getting into your “fat burning zone” is the best approach.
Others who say that high-intensity intervals (HIIT) is the most effective approach.
Others who say that weight training (resistance exercise) is the best.
(And you even have people out there like Gary Taubes who think exercise is just a big waste of time that doesn’t work at all, because they think that it will just make you hungrier, and you will eat more calories and cancel out the calories you burned off. He is entitled to his opinion, but dozens of studies prove him wrong, showing that exercise is indeed a major key to losing fat and keeping it off for life. Not to mention, countless proven health benefits. But let’s get back to the point.) …
So who’s right? What’s the best type of exercise for fat loss–cardio, intervals, or weights?
STUDY #1 – Cardio vs. Weights vs. Weights + Cardio vs. Gentle Movement
First, let’s talk about a new study from Benito et al., where researchers had 96 obese people complete a supervised 22 week protocol of various kinds of exercise, in conjunction with a calorie restricted diet.
They were divided into 4 groups:
1) Weight training
3) Weight training + Cardio
4) Light movement throughout the day (taking the stairs instead of the elevator, including brisk walking throughout the day, gentle movement/NEAT.)
(Note: The diet was the same for all groups–only the type of activity differed).
Study #1 Results:
ALL subjects lost about 9-10kg of body mass and decreased bodyfat mass by about 5kg.
The scientists were NOT able to detect a significant inter-group-difference between the four study groups.
STUDY #2 – Cardio vs. Weights
Next, let’s talk about a study from Bryner et al., published in the Journal of the American College of Nutrition. This study put subjects on an 800 calorie diet and then divided participants into two groups. One group went on a cardio program where they did one hour of cardio exercise (walking, biking, or stair climbing) four times per week. And the weight training group were asked to train with weights in a fairly demanding workout routine three times per week.
The researchers then looked at changes in body weight, body FAT, and metabolic rate after 12 weeks.
Study #2 Results:
The cardio group lost more overall bodyweight than the weight training group–the cardio group lost 37 pounds, while the weight training group lost only 32 pounds.
However, when you look at the change in body FAT (not just bodyweight), the results become much more interesting…
The cardio group did indeed lose 5 more pounds than the weight training group, BUT 10 of those pounds came from MUSCLE, not FAT.
The weight training group lost 32 pounds, and all 32 of those pounds were from FAT. They lost 0 pounds of muscle.
So in reality, while the cardio group lost more scale WEIGHT, the weight training group lost 5 pounds more body FAT.
In addition, the cardio group’s metabolic rates declined, while the weight training group’s metabolic rates were not only preserved but actually increased slightly! That is a key factor when it comes to keeping the weight off, since we know that loss of muscle mass and decreased metabolic rate predispose to weight regain.
So here, the clear advantage goes to the weight training group when it comes to fat loss.
And this effect is likely to be further amplified over longer periods of time, since those who lose more muscle mass are more likely to regain the weight.
(Note: Why did this study’s results differ from the first study? The answer is likely pretty simple: The weight training regimen was more intense, so it created a greater stimulus to retain muscle mass.)
Study 3 and 4 – Cardio vs. Intervals (and their effects on food intake)
So far, we have looked at a couple studies in people who have had their diet controlled–meaning they’ve all been forced to eat the same diet with exactly the SAME amount of calories during the experiment. Let’s now look at the real-world research comparing cardio vs. intervals (HIIT) and see what kind of effects they have on fat loss when people are free to eat whatever food they want. (That’s pretty important, because it’s the situation pretty much all of us are in).
The first was a Harvard study that looked at 64 people training for a marathon (4 days a week) and simply tracked how much weight and fat people lost as they were running upwards of 30, 40, and 50 miles per week.
The second study compared food intake over the course of 12 weeks in two different groups–one that was doing moderate-intensity aerobic exercise (cardio) and the other doing HIIT.
Study 3 and 4 Results:
The Harvard study with marathon runners study found that even when training for a running a marathon, many people don’t lose any fat whatsoever.
78% of the 64 participants did not lose any weight at all.
And 7 people actually gained weight. Let me remind you, that’s after training four times a week for three months!
According to the lead researcher: “Marathon training has little or no effect on most people’s weight, scientists say. Many long-distance runners find that even when they are running more than 50 miles in a week their waistlines barely get smaller, with some actually gaining weight.”
What causes this effect? Most research indicates that it’s a combination of a few things:
- The effects on appetite regulation (endurance exercise doesn’t seem to suppress appetite and actually seems to increase it, in a large portion of people)
- People overestimating the amount of calories they’re burning and/or rewarding themselves with food for doing the exercise. In other words, people get hungrier after going for a run, and they overestimate how many calories they burned off and end up overeating.
Ultimately, for many people, it’s a recipe for dozens of hours of exercise and months of hard work to ultimately not notice much of an effect.
What about intervals and high-intensity interval training (HIIT)?
You’ve probably heard many people write about high intensity interval training (HIIT) and fat loss, and that the benefits of HIIT for fat loss come from the “after burn” effect where the body burns extra calories for several hours after the workout is over.
More and more research is pointing to the notion that this is inaccurate. While it is true that the afterburn effect is about 3x larger in HIIT compared to cardio (and is potentially a small factor in fat loss), the bulk of the research indicates that it’s not the afterburn effect that’s important in creating the fat loss superiority of interval training–it’s actually that high intensity interval training tends to suppress appetite and causes a decrease in overall calorie intake.
And that’s exactly what Sim et al. (2015) found in their study looking at the effects of cardio vs. intervals on appetite and food intake–a very significant and large reduction in appetite in those on the HIIT program.
Why is this important?
Because if you’re doing a form of exercise (e.g. cardio) that doesn’t suppress appetite very much, you might spend months doing hours of cardio and have little to no results to show for it, because you’re compensating for all the calories you are burning with increased food intake.
HIIT seems to be much less prone to this food intake compensation, which is why it creates better fat loss results.
Study 5 – The Highest Level of Evidence
Here is the granddaddy of scientific evidence on this subject–the systematic literature review and meta-analysis. What is that? It’s not really a study, it’s basically a compilation of all the other relevant studies on this topic. Because of that, this is considered to be the highest level of scientific evidence.
This 2015 meta-analysis by Clark et al. compiled the data from 66 studies on the topic, crunched the data, and found some fascinating results…
Study 5 Results
What did they find? First, they found something critically important to understand: that fat loss did NOT correlate very well with the extent to which a treatment is effective in establishing a calorie deficit. In other words, just adopting an approach which creates a calorie deficit is NOT enough to generate lasting fat loss. To generate lasting fat loss, they suggest that we think less in terms of CALORIES and more in terms of the metabolic DEMAND being placed on the body.
Here are their words…
“While popular ideas suggest the necessity for acute energetic imbalance, there appears to be no relationship between any treatments effectiveness for inducing acute changes in energetic balance with the effectiveness for induced responses to body composition or biomarkers of health from said treatment program. All of which reinforces the idea of a more complex network of factors that influence overall body composition and health issues for the adult who is overfat, and further stresses the idea to focus treatment on generating a metabolic stress to induce chronic (hormonal) changes as opposed to the focus on the calorie ratios of intake to expenditure.”
This explains why simple forced calorie restriction and fasting approaches to fat loss have such abysmal success rates. Just starving your body of calories does not work very well in the long term. In fact, it works pretty terribly. What does work is putting metabolic stress on the body.
Most importantly, what they ultimately found is that the most effective type of exercise for fat loss is resistance exercise!
Second to that, they found that high-intensity interval training (HIIT) or high-intensity steady state exercise (high-intensity cardio, above 70% of your max heart rate) can also be effective.
SO WHAT’S THE BEST TYPE OF EXERCISE FOR FAT LOSS?
Okay, so by now, you’re probably thinking “Enough with the science, Ari! Just tell me the bottom line of what type of exercise to do for fat loss!”
Let me summarize all of this in 7 key points:
1. Nutrition is critical for fat loss.
This is what allows fat loss to happen, and without a solid nutrition program that drives fat loss, virtually all exercise programs will be minimally effective. (If you don’t yet understand how to optimize your diet to drive fat loss, go grab my program The Forever Fat Loss Formula).
2. NEAT is the foundation for good metabolic health and body composition.
The foundation for physical activity for fat loss is to increase gentle movement/NEAT–and DECREASE sitting time, and stationary time–as much as possible each day. (Note: If you don’t know what NEAT is, then watch this video from 33:00 to 44:00). ONLY once you have this foundation should you then even worry about whether you’re doing cardio vs. weights vs. intervals vs. whatever else. Why? Because without ample NEAT each day, you’re mostly just spinning your wheels, since sitting time will CANCEL OUT most of the metabolic benefits from your workouts. (See here if you want to read more on that research.)
Also note that many people don’t get results with high-intensity exercise because they are NEAT-compensators. In other words, they compensate for the workout they did by sitting around more after the workout is over. If you want to achieve fat loss, you need the solid foundation of NEAT.
3. If you’re extremely overweight and entirely sedentary, it likely doesn’t matter very much what type of exercise you start doing–anything will work.
Pretty much all types of exercise will result in large benefits. And there won’t be large differences between exercise types in terms of fat loss. The fitter you get, the leaner you get, and the healthier you become, the more that exercise type begins to matter more for changing your body.
4. Fat loss is NOT just as simple as “calories in, calories out.” You need to put a metabolic demand on your body.
There is a reason that the research favors the more metabolically-demanding forms of exercise as being the most effective. And there is a reason that forced calorie restriction diets and fasting approaches have absymal long-term success rates for fat loss. The reason is that body fat regulation is a complex process that involves a whole network of hormones and brain regions.
Simply trying to starve your body of calories will absolutely cause short-term fat loss, but it isn’t going to get you very far in the long run.
As the meta-analysis explained above, losing fat is NOT just as simple as restricting your calorie intake.
We need to reconceptualize fat loss AWAY from “starve your body of calories” to “create the metabolic demand on your body so that it wants to change.” A calorie not eaten is not the same as a calorie burned, because depending on how that calorie is burned, it will stimulate different adaptations and hormonal responses in the body that will impact health and body composition differently.
The research indicates that the effectiveness of the approach is determined less by how much it starves the body of calories, and more about how much it creates a need for the body to change. And this is why we know that:
- Approaches that involve exercise are more effective than diet-only weight loss approaches
- Metabolically demanding exercise like weight training or HIIT are typically more effective than low intensity exercise.
Stop thinking so much about everything as a simple matter of “burning more calories” and “eating fewer calories” and start thinking about how you can introduce some metabolically demanding exercise into your life. If you do, you will get better fat loss results. And that’s especially true if you follow the advice in the next few points…
5. The most effective type of exercise for fat loss is resistance exercise. (And more specifically, a progressive and periodized resistance exercise program.)
This is because it will lead to the best preservation of muscle mass and the “weight” that the body will burn off will come from fat instead of muscle. In addition, it also will lead to the best preservation of metabolic rate. That’s important because loss of muscle mass and lower metabolic rate predisposes to weight regain! One of the biggest weight loss mistakes that people make is going on a diet while NOT doing any form of resistance exercise. Yes, you’ll lose lots of weight on the scale, but lots of it is coming from MUSCLE, which is going to make you much more likely to regain the fat. Weight training is critical during all periods that you’re trying to lose fat. Not only is it going to help you lose more fat, but this is a key factor in bulletproofing your body against weight regain.
(If you’re brand new to resistance exercise and looking to get started, I recommend starting with a bodyweight-focused resistance exercise program. Natalie Jill’s Stronger program is the best one I have found. If you’re already doing an exercise program and you’re moderately fit, then go grab the Supershred program that I co-designed with Natalie Jill).
6. The next most effective type of exercise for fat loss is high-intensity interval training or high-intensity steady state exercise.
If you don’t like resistance exercise, you have options. Most importantly in your decision making process of what type of exercise routine to do, choose a kind of activity that YOU LOVE TO DO FOR IT’S OWN SAKE and that you’ll stick with for the rest of your life. If you don’t follow this advice, then nothing else matters, because even if you do some exercise routine for 60 days of 90 days, if you then STOP doing that particular routine because you don’t like it, you will slowly LOSE all of the results you got. So find a type of exercise that you LOVE (or at least like) and can continue to do for life. Ideally, that would be resistance exercise or high-intensity interval/cardio exercise. But if you love going for gentle walks, bike rides, or dancing, then realize that consistently doing something–even if it’s not optimal–is much better than not doing anything. As with nutrition and every other lifestyle change, the only exercise changes that matter in the long run are those you can sustain for life.
7. How to design the ULTIMATE fat loss exercise regimen.
So let’s say you wanted to put together all of the research into one ultimate fat loss exercise regimen… let me show you what that would look like:
- Have a foundation of ample gentle movement or NEAT during the day
- Do resistance exercise (on a progressive and periodized program) at least 3-4 times per week
- Do high-intensity interval training or high-intensity steady state cardio (above 70% maximum heart rate for 30 minutes or more) at least 2-3 times per week
- Optional: If you would like, you can also add in lower intensity cardio activities for health benefits or fun
(If you want to cut out the guess work of trying to do this all yourself and get yourself on a professionally-designed exercise program that follows this exact ultimate fat loss blueprint, then go grab the Supershred program that I co-designed with Natalie Jill. It’s a cutting-edge resistance exercise and high-intensity interval training program designed to take your body to the next level.)
There you have it! You are now armed with the latest science around the best types of exercise for fat loss.
So if you’ve been following a physical activity regimen that doesn’t match up with this blueprint, it’s time to change that and start dropping the fat. 🙂
1. Benito, Pedro J., et al. “Change in weight and body composition in obese subjects following a hypocaloric diet plus different training programs or physical activity recommendations.” Journal of Applied Physiology (2015): jap-00928.
2. Bryner, R. et al. (1999). Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate. Journal of the American College of Nutrition. 1999 Apr;18(2):115-21.
4. Sim, A. et al. (2015). Effects of High-Intensity Intermittent Exercise Training on Appetite Regulation. Medicine & Science in Sports & Exercise: November 2015 – Volume 47 – Issue 11 – p 2441–2449.
5. Bagley, Liam, et al. (2016).”Sex differences in the effects of 12 weeks sprint interval training on body fat mass and the rates of fatty acid oxidation and VO2max during exercise.” BMJ Open Sport & Exercise Medicine 2.1: e000056.
6. Clark, J. (2015). Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight-loss and changes in fitness for adults (18–65 years old) who are overfat, or obese; systematic review and meta-analysis. J Diabetes Metab Disord. 2015; 14: 31.