Marathon training & weight gain

Hello everybody,

I am getting quite frustrated. In 2011/2012 I lost more than 15kg, dropped from tight size 14 to comfortable size 10 - so VERY HAPPY! I did bootcamp 3x a week and changed my diet (eating more regularly, 3 main meals + 2-3 healthy snacks a day etc.) - but I had to count calories to have control. I started to run a bit in September 2012 and then regularly (2x a week) in October and I have been training for my first ever marathon since beginning of December (3x runs a week) + still doing about 2-3 bootcamp sessions/week. I also stopped counting calories beginning of October. I have not a body of a runner - more like a powerlifter, I would say - somewhere between Mesomorph and Endomorph. I have sturdy legs and quite strong muscular upper body, but cannot get rid of my belly fat.

The problem is that since this summer I have gained about 3kg of weight and recently (since I started running regularly) I have been putting on more weight... slowly, but surely. I know my diet is not perfect and I may eat too much to LOSE weight, but not so much that I should gain it, with all that training.

Is it possible that my regular running / marathon training is the main cause of my current weight gain?  (But I am sure I have put some fat on, too, not just muscle)

Thank you for any response / experience.



  • The more I train the more I put on weight.this is because i overcompensate for the exercise.......i think.. I'm training 12/14 hours a week i can eat what i want.but i'm greedy and eat way to much.

    to lose weight i have to stop training and note everything i eat........

    try writing down what you eat .see if it helps

  • Eggyh73Eggyh73 ✭✭✭

    If you are gaining weight with all that training it's most likely eating too much, or more to the point eating too much of the wrong foods. I tend to shed a bit of weight when marathon training, but my weight is reasonably consistent.


  • Calories in vs calories out determines whether you gain or lose.

    If you are gaining weight you have a net surplus. Lots of people massively overestimate how much a bit of exercise burns. Diet is the biggest factor in determining what you will weight.

    You mentioned you tracked calories before why not do it for a couple of weeks again just to monitor, I'm sure you'll be able to figure it out from that.
  • perhaps its muscle gains?

  • Are you gaining fat or muscle?  Muscle weighs twice as much as fat - in which case you can think of it as 3 kilos of fat you don't have!  If it's just a bit of extra fat, try counting the number of calories you eat.  It's often a lot more than you think.  

    In excess calorie terms,3kg over six months is really minor.  It takes about 3500 excess calories to gain a pound, so that's 23100 excess calories over six months.  Divide that up by 180 days and you've got 128 extra daily calories you don't need.  That's only one healthy snack too many - it hardly sounds as if you're rewarding yourself for a run with a packet of hobnobs!

    Congrats on the original weight loss, anyway!  You've done really well to shed so much in what sounds like a really healthy way image

  • I think it can be pretty common to overestimate the kcals burned with exercise (usually forgetting to account for the fact that you would have burned a hundred or so in an hour from doing your usual stuff without "exercise").  It's worth checking your body fat % though (which is often forgotten), I'd rather put on weight and reduce fat, than what happened after my last marathon - I stayed exactly the same weight but over 3 months put on 6-7% body fat image due to not running.  Fully reversed now - yay!

  • Worth taking body fat% into account - after my last marathon I stopped running, but kept practically the same diet (schoolboy error, I know).  In 3 months I was the same weight give or take 1Kg, but nearly 7% more body fat!  All just about reversed now since Christmas, thank goodness.

    I think it can also be easy to forget your basal rate of calorie burning - the hour of exercise is fine, but you'd have burned around a 80-100 not exercising at all.  I've realised that in some people it is a very fine balance and overeating by a hundred or so calories a days is incredibly easy to do without realising.

  • daisyjess wrote (see)

    Are you gaining fat or muscle?  Muscle weighs twice as much as fat -

    How? 1kg of muscle weighs the same as 1kg of anything else.



  • GraemeK wrote (see)
    daisyjess wrote (see)

    Are you gaining fat or muscle?  Muscle weighs twice as much as fat -

    How? 1kg of muscle weighs the same as 1kg of anything else.



    Exactly.... it is just more dense than fat so takes up less space..

  • I tend to put on more weight during marathon training. I do eat more after exercise, maybe more than I should, but I'd rather that then affect my immune system etc by not recovering and being ready for the next run..

    You are  attempting to change your physiology in marathon training. For example, you train yourself to store more glycogen. This increase in glycogen retains 2 - 3x water for each gramme glycogen.

    I think its a complex question, not just a simple 'carbs in carbs out' equation. If it really does concern you, get a body composition analysis for you know what fat, lean muscle and water you are carting around with you. Get retested in a couple of months.

  • This study is interesting which showed a weight loss in males, but a slight weight gain in females who undertook a marathon training programme. The gain was very slight though:

     As a male, I need to go and find another bit of research to justify my weight gainimage

Sign In or Register to comment.