Cardio While Cutting Causes LBM Loss?

Justin_7272
Justin_7272 Posts: 341 Member
in Goal: Gaining Weight and Body Building
I've read doing cardio while cutting can increase LBM loss (most speculate it's due to your body dipping beyond glycogen storage).

My reason for cardio would not be to increase my deficit, but rather to allow more intake to be able to hit my macros by eating back exercise calories.

If I'm eating back cardio calories and keeping protein at roughly 1.5 g/LBM will this still cause increased LBM loss?

Assuming I'm able to at least maintain my lifts, is this really an issue?

*Please note - I know low deficit over a long period is healthiest and ideal; I'd like to keep the post focused on the questions at hand from a more scientific/anecdotal standpoint. Thanks!

Replies

  • sijomial
    sijomial Posts: 19,809 Member
    edited November 2019
    Cardio is a huge range of intensity and duration - are we talking about an easy short run or a 100 mile cycle ride?
    Are we talking about a moderate deficit or a fast rate of loss?
    Are you already very lean aiming to get ultra lean?

    Your body doesn't easily "dip below glycogen storage" if by that you mean bonking (as cyclists call it) or hitting the wall (runners) as you can barely function when that happens. There's no mistaking when it happens and it takes extended endurance cardio and underfuelling to achieve it.

    BTW - you don't use glycogen and then fat, it's a blend of both 99% of the time.
  • Justin_7272
    Justin_7272 Posts: 341 Member
    Currently 175lb (20-25% bf) aiming for 150-155lb. Looking to drop 1.5-2lbs per week.

    Started the year around 185. Started cycling an hour a day (450-600 cal) with defecit and hit 160 by July, which is when I realized I should have been lifting, so I started to lift with caloric surplus.
  • sijomial
    sijomial Posts: 19,809 Member
    Justin_7272 wrote: »
    Currently 175lb (20-25% bf) aiming for 150-155lb. Looking to drop 1.5-2lbs per week.

    Started the year around 185. Started cycling an hour a day (450-600 cal) with defecit and hit 160 by July, which is when I realized I should have been lifting, so I started to lift with caloric surplus.

    Personally I would lose slower (your stats are similar to where I was) but mainly for ease of adherence and exercise performance reasons.

    For what isn't an extreme amount of exercise and you not being lean I don't think muscle loss (as opposed to LBM loss as LBM isn't just muscle) is a serious concern if you are doing the right things in terms of strength training and protein intake.

    There's a feedback loop of hunger, exercise performance, recovery and strength progression that are sensible to take into account as your cut continues.
    e.g. losing quickly from 175 to 165 may not cause any issues but that's no guarantee 165 to 155 will be the same.

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