Is Fasted Cardio The Best For Burning Fat?
Name: Jim Stoppani, PhD
Occupation: Creator of JYM Supplement Science, fitness coach and consultant
I'm often asked whether mornings of fasted cardio are the best way to burn fat. My answer is yes ... and no. When it comes to the physiology and biochemistry of the human body, nothing is simple. Throw exercise on top of normal daily functions, and things become even more complicated. So what do the experts say?
Some research does actually show that when you do cardio fasted in the morning, you burn up to 20 percent more fat. A recent study from the UK published in the "British Journal of Nutrition" found that when subjects were fasted during morning cardio they burned 20 percent more fat than when they had a meal beforehand. Several earlier studies show similar results.
Fasted cardio in the morning is effective because as you sleep and fast overnight your body conserves its precious carb stores and leans toward mobilizing fat for fuel. The story doesn't end here, however. Your body also breaks down amino acids into glucose overnight, so fasted morning cardio mobilizes more fat and potentially more amino acids for fuel, which isn't ideal if building muscle is your primary goal. This isn't a huge problem as long as you consume a fast-digesting protein like whey, along with some slow-digesting casein, after your cardio.
The HIIT On Cardio
Despite the evidence above, we can't unequivocally say that fasted cardio is best for burning fat. Many studies on fasted or fed cardio focus solely on how many calories are burned during exercise. This is problematic because the real benefits of exercise, particularly high-intensity cardio and lifting, come after training. High-intensity training burns more calories and fat after a workout than low-intensity cardio. With high-intensity interval training (HIIT), you burn calories for the rest of the day, even when you're not doing anything.
Studies show that HIIT workouts—which take far less than half the time of slow-and-steady cardio workouts—lead to as much as twice the total fat lost. Even though the slow-and-steady cardio programs burned more total calories and fat during the actual workout, the HIIT programs somehow led to greater total fat loss. This is because the HIIT workouts burned more calories and fat the rest of the day, which adds up to more calories and fat than you can burn during a single workout.
So, if you're like most people, your best bet is to not worry about doing cardio fasted first thing in the morning. If doing cardio first thing in the morning is best for your schedule, then go for it, but try to at least have a pre-workout protein shake. If your goal is building max muscle, then I highly recommend you have a protein shake and some carbs, such as fruit, before the workout. If you're trying to limit carb intake, then you might want to avoid the carbs until after the workout is over. But again, it all depends on your diet.
The Stoppani Solution
That being said, I personally do a bit of fasted cardio and recommend it for certain people at specific times. I found that fasted cardio can work well for men with body fat in the low single digits (5-6 percent) and females with body fat in the low teens (13-14 percent), especially if they have specific problem areas like the lower back or thighs.
Over the years, I found that once people drop the majority of their total body fat, fasted cardio seems to work well on resistant or stubborn areas. Although there's no direct data to reference, it might be that when a person only has a small amount of fat lingering in hard-to-attack areas, exercising in a fasted state could spark those resistant fat cells to release stored fat so it can be burned for fuel.
However, if you're a male with roughly 8 percent body fat or more, or a female with 16 percent or more, fasted cardio probably won't make a massive dent in your fat-loss efforts. Instead, go high intensity with some form of HIIT and watch the fat melt.
- Gonzalez, J. T., et al. Breakfast and exercise contingently affect postprandial metabolism and energy balance in physically active males. Br J Nutr. 23:1-12, 2013.
- Deighton, K., et al. Appetite, energy intake and resting metabolic responses to 60 min treadmill running performed in a fasted versus a postprandial state. Appetite. 2012 Jun;58(3):946-54.
- Hansen, K., et al.. The effects of exercise on the storage and oxidation of dietary fat. Sports Med 35: 363-373, 2005.
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I have read recently fasted cardio burns more calories during the actual workout, but eating some protein and carbs before the morning cardio will actually help to burn more calories throughout the day.
Very interesting article. I have found studies about this from various sources and everyone feels somewhat differently about what is best for fat lass. However, I find the idea that HIIT helps burn more calories throughout than the slow steady cardio very intriguing.
I also think it depends on what your overall goal is. For example a distance runner doesn't really want a lot of muscle mass because it is heavy, while a sprinter is looking for strong muscles that can explode. Each runner is in shape, but their bodies look different because of how they train. I'm sure there are thins that overlap, but like Dr. Stoppani mentions it is important to consider what your fitness goals and diet plans are.
I think both types of exercises have their advantages and place in someones workout schedule.
I have been doing intermidiate fasting per the researched done by Sara Solomon. I feel leaner and not as bloated. However since of my work schedule I can not train or do cardio in the morning. I have the last fat in my midsection and trying to desparetly get rid of it and this article is exactly what I needed. I will be doing fasted cardio about 3 days a week and HIIT about 3 days and no cardio on my leg day! Leg day is like a religion you got to pay respect to your legs.
Focus on your diet.
Nutrition>weight training>cardio. Oh and by the way, you're doing too much with 3 sessions of fasted cardio and 3 rounds of HIIT.
You have no time to recover.
Just a minor correction: it's intermittent fasting, not intermediate.
Anyway, I agree with Antonio; I would only do one of the two options (or you can combine them: do fasted HIIT.) Go hard--very hard--and then relax. Your fat percentage isn't high to begin with.
I appreciate your input. Suggestions are always welcome for me. I am just in a situation where I can't lose the last fat on my midsection. Please excuse my spelling I am working and just thought I share what I am planning on doing.
My coach has me doing HIIT 5x a week for 1.5hr. Just started doing fasted for 45min and ended up dropping a ton of weight. If your body is up to it then go for it! To look like an athlete have to train like one is my philosophy. I'm highly conditioned apparently so what seems extreme to some is normal for and works for me. Just reintroduced intermittent fasting to my life last week and dropped 3 lbs, so the lower abs are finally showing!
@Simplymeinpa thank you now I don't feel so bad lol. I completely agree with you that what's extreme to others might not be to you. Males always tend to want the big muscle mass. I want to be a little more cut. Thanks so much!
I am always looking for ways to burn body fat. I am trying to get down to 15% or less and have a ways to go. I usually do my cardio at night due to my schedule but if this is legit then I might have to start my cardio in the morning.
Nice article once again Jim ! Thanks a lot ! 1 min burpee , 30 sec rest , 1 min high knees , 30 sec rest , 1 min push with knee combination 3-5 rounds is it good ? after weight training 2-3 times a week
Fasted cardio has always worked for me and I usually do 30 minute sessions, 3-5 times per week. I'll have my "casein pudding" before bed and when I wake up (waiting for my coffee to brew) I'll drink some BCAA's and L-Glutamine, then sip on the rest during my fasted cardio.
I also love HIIT cardio and incorporate that into my routine as well.
I do both. Fasted steady state cardio first thing in the morning followed by a protein shake. Then HIIT cardio in the afternoon after a glycogen depleting workout, followed by a protein shake. BCAAs during my workout. I've been on a cyclic keto diet for years and frankly dont need carbs.
"I've been on a cyclic keto diet for years and frankly dont need carbs" Would you mind sharing your protocol? I have been on Keto now for a few weeks, I great for a few but now I've become stagnant.
Agreed! I always thought HIIT would wear me down after a hard lifting workout but I'm finding the opposite to be true. I can't seem to psyche myself up for a HIIT workout first thing in the morning or right before I lift but once I've down some lifting and had a small cool-down period, I feel like I could go another round.
As a former track athlete. I've done my fair share of running in the mornings. I've seen fast fat loses for sure, but make sure to not over do it. Run until you feel really hungry, but stop there. Good article for sure.
I do them both. Fasted and HIIT. Let me tell you, my body responses really well to fasted cardio. As mentioned in the article, the stubborn areas start to lean out plus it gives me energy for the day, my body feels light)))
Fasted Cardio helped me drop alot of pounds when I first began this journey...I'll never know if I would have dropped the same amount as quickly if I were to fave did cardio later in the day after eating, but fasted cardio worked VERY WELL for me..