High intensity vs. low intensity cardio for fat loss?

(Eli Miles) #1

Been keto for 4 months and been back in the gym for the last month. Wondering if anyone has any suggestions as far as which type of cardio is best for fat loss while keto. I typically do my cardio on a treadmill. I’ve done both forms a few time and have considered combining the two and am wondering if anyone else has experience they could share.

(Mark) #2

My vote is for high intensity sprints on a stationary bike mark sisson the paleo guy was a marathon runner and said it ruined his body and now does sprints on the beach which are killer by the way,I’m glad I finally gave up on exercise for fat loss and focus more on keto and fasting,I just use exercise to improve stuff like blood pressure and sleep

(G. Andrew Duthie) #3


Eat for fat loss (i.e. what you eat).

Exercise for health.

Not saying exercise won’t help at all. Just that it isn’t the primary driver of fat mobilization.

And if you haven’t fixed the eating side, and insulin is still high, you can exercise whichever way you choose and it is unlikely to move the needle at all.


You will not get sustainable fat loss with exercise. Your food and feeding choices will be the main driver for fat loss.

Exercise for other reasons…toning, cardiovascular endurance, etc.

(Eli Miles) #5

Yeah i focused solely on keto for the first 2 months and lost 43 lbs(284-241). Added in some IF as well as a 5 day water fast in months 3 and 4 lost another 32.5lbs(208.5). I’m doing cardio mainly because i fell like doing it and i fell better afterwards. But figured if i am going to doing it and one works more effectively then i would focus on that type of cardio.

(G. Andrew Duthie) #6

Best type of exercise really depends on your goals. More effective for what?

(Eli Miles) #7

My initial goals were to reduce my weight and a1c levels and i have done so in the last 4 months. So my main goal now is to reduce body fat. I would guess i am somewhere in the 25 percent range and would like to get it down in the teens. I will eventually add in weight lifting but currently have no desire to do so yet. I do find my self wanting to do some cardio. I figured if one was more effective for fat loss then i would focus on that type of cardio. But i didn’t realize they were that ineffective at it. I will continue to do it for overall health benefits. I will just do whatever type of cardio i fell like doing at the time and continue with the fasting and of course the keto. Thanks for the input it is greatly appreciated


HIIT will give you the best cardio benefits per time spent on exercise. Just be sure you are healthy enough first. You don’t want to jump into intense exercise right off the couch. Likewise, keep the impact low to avoid injury.

(Sascha Heid) #9

I’m sorry but this is all crap. It doesnt matter what you do on a treadmill, it is useless.
Go outside, the sun is as critical for our health as our food. Enjoy the cold fresh air, the snow, the rain, the sun, the wind, the open space around you. Indoor cardio is idiotic, you will not get healthy this way.
If you are afraid of the cold HIT will fix this for you. After your second sprint you will not be cold, not even in canada. Its f*cking awesome.

(Ben) #10

Ted Naiman explains the difference between low and high intensity exercise here (2nd video)

(The first vid is pretty good too - nice summary of LCHF)


Of course exercise can help mobilize fat for fat loss. It seems some are suggesting not exercising for the purpose of fat loss. While it is true that exercise should not be the primary focus for fat loss (diet should be) it is short sighted to dismiss the power of exercise to mobilize fat, especially in a fasted state.

That being said IMO the best value for time is high intensity interval training. You simply get more value for your time than long low intensity cardio. I believe exercise physiology science shows greater fat mobilization overall with this type of exercise as well, but I am not 100% sure its settled.

(betsy.rome) #12

Can a couch potato keto person start HIT without hurting themselves? I’ll be starting on stationary bike. Sedentary because of knee issues (one TKR, the other one is shot), and I know the bike is good for my knees. But really don’t need any more damage.

(Jennie) #13

I’ll respectfully disagree. Sometimes I need to move my body but I have two littles in tow and can’t justify taking them out in the -4 degree (the HIGH for the other day) weather. So I utilize indoor activity and quite enjoy my treadmill. Especially trying to sprint for longer and longer. :slight_smile: I think moving the blood and body is fun and takes on many forms. Sometimes even forms when we’re “stuck” in certain situations.

(Jennie) #14

I’ve been keto-ing for 4 months too! :smiley: Keto twins. Your losses are really amazing. There’s a lot of info here already, but I’ll throw in my two cents. I like HIIT because I get super sweaty and the shower afterwards feels euphoric. I also recall it drives down basal insulin, though I’m not positive if that needs to be fasted HIIT or not. But I also enjoy doing lots of other stuff. My suggestion would be to play and enjoy it! If you get to where you are wanting specific results in certain areas, I’d just focus on that when you get there.
Keep up all your amazing work!

(Jason Barbier) #15

Honestly based on everything I’ve learned about how the human body works, and I’m not a doc so take this with a huge ol’ pile of salted butter, you cant out exercise a bad diet.
Once you have a good diet your best bet if you are looking at making your body more lean is actually not cardio for the most part but to put on some bulk, so pretty much weight lifting. A lot of the gains people see from cardio seem to come more or less from the increased muscle mass in their legs that slowly build up over time from doing all the cardio.
Now mind you this isn’t a “you should totally shun cardio it is useless”, cardio is useful for building stamina, and a mix of high and low intensity cardio works great. There is a reason militaries for centuries have mixed body weight exercises (calisthenics) and cardio.

TL;DR and over simplified: Diet will determine your body size and composition, exercise will determine your over all efficiency and health, your muscle mass drives your resting caloric requirements. More muscle = more calories required to sustain yourself.

(G. Andrew Duthie) #16

The keyword here is “help”.

And it can only help once the issue of deranged metabolism and elevated insulin is addressed. While there are some things I’ve read that indicate that exercise can play a role in insulin sensitivity, the most effective way to address insulin is by addressing diet.

The other REALLY big advantage to addressing diet is that once you get insulin out of the way of the body being able to access fat stores, you may actually WANT to exercise, rather than trying to force yourself to. :slight_smile:

N=1, but that is exactly how my body has behaved. When I am doing keto right, I want to move more.


I don’t feel like anyone is considering exercise without " firstcorrecting insulin", but the simple fact is almost nothing is better for improving insulin sensitivity than intense exercise, regardless of the status of your health. I think on a ketogenic forum its safe to say anyone asking these questions is well on their way to addressing their metabolism issues.

(G. Andrew Duthie) #18

I’m not sure that’s safe to say at all. Someone who’s very new to the ketogenic WoE may not have had the exposure to all of this that you or I (or others who’ve been doing it a long time) have.

Given the volume and history of the message that exercise is the way to lose weight (i.e. - eat less, move more), I think it’s important to be explicit about what exercise can and cannot do. FWIW, I think we’re probably closer to agreeing than it seems, it’s probably more a matter of emphasis than disagreement.

I don’t disagree that exercise can be effective for insulin sensitivity. The issue I see is the energy partitioning issues with IR and T2D will, for many, make exercise more difficult, because they don’t have access to the stored fat for energy. Yes, you can force yourself to exercise, but experience shows that’s not an effective or sustainable strategy for most.

Hence my emphasis on addressing diet first, to move the energy partitioning lever in the direction of more available energy from fat stores. If I sound like I’m discouraging exercise, that’s certainly not my intent.

(Charmaine) #19

I do both, but what’s really helped me has been to focus my workouts on strength training mixed with cardio.

(Allan Misner) #20

You can, but your level of exertion will look different and you likely won’t go as long as someone who is trained. If you have a physical limitation (like the knee issues), be sure to consider that in planning how you do HIIT. The bike is a good choice.

Here is an approach I use with new trainees that want to build endurance using HIIT:

  1. Warm up very well.
  2. Go with a 1/4 work to rest ratio (the rest ratio may decrease as you get more fit). The plan is 8 - 10 rounds, but that depends on recovery (see below).
  3. Limit the work sessions to 20 seconds (the work sessions may increase as you get more fit).
  4. Monitor your heart rate. It should approach but not exceed your max (220 - age). And on the rest phase it should drop back below your training range ( [220 - age] x 70 ).

When your heart rate doesn’t make it back down below the training range, you’re done. Stop regardless of how many rounds you’ve done. You’ve pushed hard enough for that training session.

I hope this helps.