HIIT, weightlifting or low-intensity cardio?


(Yu) #1

Hello! So I’ve been on the keto diet for about 6 weeks now, and have yet to have any significant weight loss (-2lbs). I started adding exercises into the mix in the past two weeks (mainly lifting free weights of 5 lbs each for appx 30 mins, some ab workout videos on youtube, HIIT on alternate days, etc.). I tried to do some research about types of exercises that would help with burning fat, and many articles I came across mentioned that high intensity exercises would convert muscles to fat, and would not help in the fat loss process. I’m confused by all the contradicting information I’m reading, and I’m hoping that I could get some insight from those with experience?


(Complete legend) #2

This is physiologically impossible.

Exercise is great for you, but has negligible effects in terms of weight (i.e. fat) loss.


(aka Nick) #3

Exercise builds muscle and cardiovascular fitness (VO2max). It’s not especially helpful for reducing bodyfat. It’s often counterproductive. Keto works best when you’re eating to satiety. Satiety signals are affected by exercise, and not for the better. Some folks find that their satiety signals significantly overcompensate when they exercise. I’m one of them.

I really struggle to lose weight if I exercise. I have dropped my exercise to 15 minutes per week of weightlifting (Body by Science). Nothing else. The day after I lift, my calories typically climb to 3000kcal/day to 5000kcal/day. I never try to restrict that in any way; I continue to eat satiety and just record the food macros and kcals like I always do because I’m a data nerd. Now that I only lift weights 15 minutes per week, I’m losing weight at a nice steady pace.

Everybody is different though. Some folks aren’t affected at all and can exercise every day of the week. You may or may not be one of them. Consider reducing your exercise until you’ve been doing strict keto, and eating to satiety for another month. Once you’ve started making some progress towards your goals, and your satiety signals are sorted, slowly add just a bit of exercise to see what happens. That’s my 2 cents anyway.

Also, there are lots of things that can inhibit fat loss, exercise is just one of them. Perhaps if you told us more about your food, it would help some of the experienced folks on the board to identify something that might help you.

I wish you luck. KCKO!


(Robert C) #4

Hi @mogyu and welcome!

Most of the time people around here refer to Keto as a WOE or WOL (way of eating or way of life).
They do this because there are not really many rules, food lists etc.

Really you are following the WOE/WOL if you are in ketosis nearly always.
So, that is the first question to ask yourself - are you sure you are staying in ketosis?
Usually answering this is accomplished by using (for the most accuracy) a blood ketone meter.
Trying to guess at what to eat can result in not being in ketosis due to hidden carbs, food labels that are misleading, misinterpreting advice and just plain bad advice.

You can exercise a lot but, if you are not in ketosis, you might sit at the same weight for a long time (or even gain weight due to muscle gain) and not know why (i.e. you’ve gone higher fat but carbs are still finding their way in to your system - causing storage instead of burn).

Once in ketosis for sure (for a long time - i.e. fat-adapted) - that is when you might want to play with other levers (more exercise, IF, EF etc.).

I think most people here go for low-intensity cardio (walking) while starting up.
This is good to ensure that stress (due to intense exercise) is not confounding you.


(Yu) #5

I see, thank you for sharing your experience!

I really struggle to lose weight if I exercise. I have dropped my exercise to 15 minutes per week of weightlifting (Body by Science). Nothing else. The day after I lift, my calories typically climb to 3000kcal/day to 5000kcal/day. I never try to restrict that in any way; I continue to eat satiety and just record the food macros and kcals like I always do because I’m a data nerd. Now that I only lift weights 15 minutes per week, I’m losing weight at a nice steady pace.

That’s unfortunately my struggle, too. Previously, I was on a calorie restricted diet (less than 900 calories/day). When I first starting Keto, I started to eat more calories due to the fat, but at the same time, I was also gaining weight. I tried intermittent fasting (16/8) to see if it would help, but I struggle to consume more than 1200 calories within the 8 hour eating window.

For now, this is what I usually eat a day:
Breakfast (8am): Omelette (2 eggs + 1 tbsp heavy cream) + spinach + mild cheddar + 1 link of uncured polish sausage
Lunch (12pm): chicken thigh or salmon + broccoli & asparagus
“Dinner” (3pm): Green smoothie (half avocado, spinach, cucumber, brocco sprouts, celery, 1 cup unsweet almond milk, 1 tbsp mct oil).

I have a blood testing meter from keto mojo, and so far my ketone levels have been about 0.6 - 0.9 when I test in the mornings.


(aka Nick) #6

The food looks good to me except for the smoothie, which is a minor point. Some people advise against smoothies because grinding food into microscopic pieces significantly increases the speed that it’s digested, but plenty of people drink them and do fine. Yours looks pretty benign.

One thing that I think is very, very important is that you should never struggle with satiety. If you are satiated, you’re done eating. If you’re hungry, you keep eating. It sounds like 16:8 might actually be a reasonable eating pattern for you, if you were getting to satiety easily. Ignore the calorie numbers as best you can.

I track calories, but I never listen to them. I have no idea how many calories I should eat on a given day. If I’m hungry I eat, and if I’m satiated I stop. I avoid everything that could interfere with my satiety signals. Exercise is the worst. Artificial sweeteners are not far behind. Keto imitations of carbage like fathead pizza, keto breads, etc would be doom for me.

I’ve been doing “boring” keto for months now and I’ve found it really helpful. I eat the same 12 foods basically every day. Basic stuff like eggs, bacon, steak, avocados. I always cook/prepare them the same way. I never fantasize about eating, or cooking, or shopping because it’s always the same stuff. I get so bored with the food that I only eat when I’m hungry, and I stop when I stop being hungry. Food just becomes fuel after a while. Doing this sorted out my satiety signals almost automatically, and that’s the starting point of a good keto way of eating.

All of that said, I’m a 41 year old man that weighs 225lbs. It may be completely different for you, I really don’t know. I’m just offering my experience of what worked for me in hopes that some piece of it might be helpful to you.

I wish you the very best of luck. My advice of less exercise, and “boring keto” should be taken with a grain of salt. There are as many ways to do keto as there members of the forum. I really hope that you find yours. If you stick with it, you’ll get there. KCKO! :slightly_smiling_face:


(Joseph) #7

If you want to use fat as the primary energy source during exercise, then you need to do aerobic exercise at low intensities (tempo or lower). Weightlifting and HIIT are primary anaerobic which relays on glycogen for fuel (PCr for HIIT if done correctly) and generally for 1) weightlifting build or maintain muscle so one can maintain or increase the basal metabolic rate, and 2) energy expenditure per unit of time is greater doing HIIT and it brings about greater boost to your aerobic base (aka fitness) in a shorter period of time (measured in weeks and also short-lived).

HIIT on alternate days? Impossible! World class athletes can manage 3 a week for short periods (typically 6-8 week as prep for the “A” event for the year). Even for threshold workout, generally time to exhaustion (or close to it such as 2-3x 20 minute intervals w/5 min rest) intensity at maximum lactate steady state, it’s a stretch. HIIT as an acronym is badly abused.

Try www.owascoveloclub.com/Education_files/EXERCISE%20PHYSIOLOGY.pdf, it’s cycling-centric but a good overall crash course on endurance performance. And, weight loss is won in the kitchen (timing, quantity, & type).


(I'll trade you my bacon for your cheese) #8

@jkc THANK YOU. This is one of those topics that make me so angry. HIIT is incorrectly used interchangeably with interval training that makes you breathe kind of hard. I take my HIIT really seriously because if I’m not going to actually do it right, why bother? I’m always looking to up my cardiovascular threshold and work the super fast twitch muscles that get otherwise unaltered with conventional forms of cardio, which I also do.

I keep track of my heart rate with a really good quality heart rate monitor so I know when I’m at or above max. I hold this for 30 seconds, and I do this in 8 intervals with 1:30 rest inbetween. I do this no more than 3 times a week, and always at least 1 day of rest in between. I know I’ve done it right, not only because I can clearly tell what my heart rate is, but HIIT often creates red splotchy skin for a short period during and after the workout. Also, the urge to sometimes wanna hurl is there, as well.

I read all the time people who say they’re doing “HIIT” 5-6 days a week. This makes me want to scream.


(Scott) #9

Muscle is muscle and fat is fat and can’t change from one to the other. I am not sure if that is what you meant.

Exercise I do for fun and am currently trying to ramp up my running to see first hand how it goes with keto. When doing caloric deficit I was running 30 miles a week and lifting. It wasn’t so much that I visualized burning fat, it was to create a larger calorie deficit. I managed to lose 50 pounds and a large beer gut this way. When I slowed down I put 30 pounds back on. I am down 23 on keto now and enjoy changing things up to see how my body responds.


(Karim Wassef) #10

He’s talking about gluconeogenesis but it doesn’t convert muscle to fat. It converts lean mass to glucose.

If you do high intensity exercise, you will deplete glycogen and force the body to break down lean mass to rapidly make more glucose.

If you do low intensity, you body has plenty of time to bring in and use fatty acids and ketones… no muscle breakdown.

If you want to lose weight, it’s not about exercise… not for a long time. It’s about watching what you eat, when you eat and how often you eat.

The only exercise that could contribute is low intensity, slow, weight training to maintain muscle activation and reduce lean mass loss that’s experienced while the body adapts to using fat.

No sprints… no hiit… no running… not even jogging…

go slow and with moderate resistance… walk more… stretch to get the lymphatic system going… move around.


(Bob M) #11

I do both Body by Science (slow lifts, few reps) (about 30-35 minutes) and HIIT (about 17 minutes) in the same workout. I do one longer HIIT (about 30 minutes) on the weekends, followed by cold therapy, where I walk outside for 20-25 minutes with reduced clothing. I remain cold basically the entire freaking day.

My HIIT is 1 minute of low intensity followed by 1:30 of high intensity. I had to drop my high intensity when I moved to flat shoes:

I use a heart rate monitor to get my heart rate fairly high for my age. (Though BBS can get just as high if not higher, depending on the exercise.)

I also had to lower the amount of weight I was using in many exercises, such as farmer’s walk, lunges, hack squats on a machine.

I worked out since I was 16 or so, and never stopped working out, even while gaining 90+ pounds. Would even ride my bike many 60+ mile rides in the summer. Exercise is poor for weight loss, at least for me.


(Joseph) #12

I’m old school and the energy demand/pathway used and being trained (fatigue resistance) is PCr so anything less than 150% ish of power output at VO2 max (Peter Coe regime?) is not HIIT. 6-7x of 15-20 sec intervals with half work duration for rest (Tabata IE1 regimen at 170% of VO2 Max) is about the limit of PCr and 30 secs is the upper limit (Tabata IE2 regimen, 200% of VO2 Max with 2 min rest). If you are using HRM as guide, you not doing it right. The work interval will be over before the heart catches up (lag). Also there a wide spectrum of work intensity that can be done at max HR so how can you determine the workload? Only a few sports (cycling, running, rowing) has tools (power meter) or published standards (running) that can objectively determine it or estimate it (running without a power meter and a very fine tuned RPE).


(traci simpson) #13

I don’t think I can ever give up exercising.


(Kirk Wolak) #14

I will chime in here. I know you have been at it longer…
But I think it is important to know that SLEEP is more important than exercise.
STRESS pushes Cortisol which pushes Insulin.

Sleep reduces stress. My biggest whooshes of weight loss came on sleepy days. Not on exercise days. Now if I exercise gently (lots of walking), I sleep better. Amazingly better. Like 3.5 - 4hrs of Deep sleep and an equal amount of light sleep! That is a MIRACLE level of sleep for me at 52… I wish I knew to track it 30 years ago. OMG. I think I get 2-3 times the deep sleep now.

Diet will help you lose weight, but you have to CLEAN it for your body. I had to go carnivore, and cut my eating down to OMAD. Eating 2MAD or 3MAD I will gain weight if I am not extremely careful. 2MAD will stall me from losing weight on an eating day.

Also, running out of weight to lose stalls me. LOL…

I would add de-stressing exercise first. Like walking while listening to podcasts or music (instead of sitting). And SMILE while you are walking, looking slightly up. PROVEN to improve your mood, and decrease stress hormones!

Good Luck!


(traci simpson) #15

Exercise helps with your all around total wellness. It’s great for the brain and may even help with issues like dementia and Alzheimer’s.


(Nick) #16

I’m curious about the 3 times a week max… Why is this? Serious question.

And the correct way to do HIIT is to go as absolute hard as you can for 15-20 seconds and then rest for AS LONG AS YOU NEED in order to perform another set at 100%. If you’re watching a clock during this time you are not doing it correctly. I shouldn’t say “correctly”, but it is a huge misconception that you go 1 minute on 1 minute off (example). There should be no time frame on your rest period. Only rest for as long as you need. Obviously that time will increase as the workout goes on.

For the OP, I would choose the one that I most ENJOY. Don’t force something that makes you miserable. Go play tennis or ride a bike, or whatever! With that being said, aerobic exercises are typically suggested while doing a keto diet.


(Joseph) #17

Work to rest/recovery duration is for HIIT intervals generally falls withing 1:1 to 1:0.5. The three (3) times per week recommendation is made to optimizing the cumulative training strain the body can handle and still able to perform at the same levels the following work week. See Banister Impulse-Response model and "Training and Racing with a Power Meter for discussion on stress/strain relationship. Also see http://www.owascoveloclub.com/Education_files/EXERCISE%20PHYSIOLOGY.pdf for general exercise physiology discussion.

What you are referring to, complete rest between work intervals, are more in-line with classical sprint training or HIT. The targeted physiological adaptation of the two are very different.