Weight, What? Gaining Weight During Marathon Training



Catherine has written 26 posts on Salty Running.

Runner mom and middle school English teacher whose students often believe you can't do anything cool with reading and writing and who is relishing the opportunity to prove them wrong.

English: Balloon modelling.

Feeling like you’re going to pop? Thank glycogen. (Photo credit: Wikipedia

Did you know that when training for a distance race it’s extremely common, if not expected, for a runner to gain weight?

If you’re anything like me, the goal of losing pounds in the name of getting down to race weight may often entice you to lace up your sneakers. But now, a few weeks of solid training have come and gone, and those mocking, digitized numbers on the scale aren’t getting smaller. In fact, they’re slowly creeping in the wrong direction!

How could we gain weight during peak marathon training when we’re running longer, farther and harder than ever?!

Let’s take a look at why runners might gain weight during marathon training and what we can do to prevent it from happening. 

  1. Runners are hungry  hangry!

Running makes us hungry. Personally, like a small child, when I am not fed immediately I get angry. This leads to the condition that you may or may not know of: hangriness. Last night I ate two bratwurst sausages for dinner and a giant bowl of ice cream for dessert. Clearly, I am not a nutritionist so, food choices aside, I notice that what used to satisfy me now leaves me feeling empty. I feel entitled to my big portions. At the moment, each calorie feels so deserved. I can routinely be heard saying,  “I ran xx miles today!” God save you if you try to correct my choices or limit my food. We can chalk this phenomenon up to low blood sugar and knowing you burned major calories.

Eastern Chipmunk with cheeks filled of food su...

After our long runs we be like…(Photo credit: Wikipedia)

What can be done: Some people might find it helpful to track their calories in and calories out.  I’ve had reasonable success with SparkPeople or using an app like MyFitnessPal. If you want a more complete review of these, this LifeHacker article is a pretty good resource. But honestly, I usually do that for about a month before I either get way too obsessive or I forget and get really sloppy about the whole endeavor.

Others might prefer a more intuitive approach. I prefer this. While training this time around, I am going with this. For me that means not letting myself go too long between meals, eat more bulky, low calorie foods, and stop acting like I’m so awesome that I can have sundaes every night. Instead, I will start by having them every other night. Maybe in the fall I’ll cut that to every two nights … although that might be a little ambitious.

2. Runners retain water 

Like camels gearing up for an expedition across a desert, our bodies know that we are using calories and water in a different way when we start logging long distances. To adapt, our body hoards glycogen, the quickest form of energy. Thankfully for our running and unfortunately for our weight, “every gram of glycogen carries with it 3 grams of water,” meaning that we are able to hold on to more water and more energy to keep us going, but we also see that weight on the sale.

What can be done: Chill out and remember that a little bit of weight gain is normal and can be a good thing! However, I need to remember that retaining water can be affected by my intake of sodium and my dehydration. For me, I feel like a balloon when I eat salty things like Chinese take-out or when I don’t drink enough water. I figure that when I have all these extra glycogen stores, this normal process for me might be accentuated.

3. Runners are jacked

Running can put on muscle mass. My husband noticed today that I’m looking a little more muscular lately.  It makes sense that with our added running, we are building up those quads and glutes, adding poundage on the scale since our less dense fat may be burned away and replaced with solid muscle. This probably means you’ll be smaller in general. However, it will also mean that there will be more to haul. Hopefully those new muscles can power you through that, though.

English: Lifting a mini car and platform with ...

Runner legs are dense and ripped (Photo credit: Wikipedia)

What can be done: Make the tape measure your friend and focus on the good you’re doing. Personally, I’m going to continue cross-training and lifting weights, even if it means I’m bulking up a bit. This is something very typical for me as my body type tends to pack on muscle quite quickly. The reason that I’m keen to continue is simple: I don’t want to get injured. I don’t care if I get a little heavier (focus on little) because I know that those muscles will protect my knees, back, hips and feet as they endure the stresses of 26.2 and ambitious weekly mileage goals.

4. Runners love GU

Salty wrote a great post about training without gels where she contends that our over-reliance on energy gels, chomps, wafers and drinks during our training could contribute to holding on to excess weight. Our running bodies are never accessing our fat stores because we’re so scared of bonking or maybe because we like the sweet reward of sucking down that jelly goodness.

What can be done: Wean yourself off the sugar. This is so hard for me because I’ve actually contemplated snacking on my chocolate peanut butter gu’s — they’re that good. However, I have been extending the time that I take in gel, moving from the 45 minutes marked on the package to more like 1 hr and 15 minutes. If I continue to stretch this out, the idea is that on race day my body will be used to training with little, but that when I give it just what it needs, it will go even faster. Of course, I have to balance this with not feeling like absolute poop after my training long runs. I do have a life and two kids that need me to be somewhat functioning for the rest of the day.

So, deep breaths as you get used to your new (slightly higher) weight. It’s temporary and hopefully minimal. I say minimal because I did find a nifty site that does some fancy calculations based on running times and weight. See my results below (am I really going to share my weight with the world? Yes, I guess I am.) As you can see, a person might get faster by losing weight. However, after reading more, you would see that losing weight by not feeding yourself adequately after a run would lead to less glycogen and lower muscle mass. Instead, your aim should be to gradually lose fat through the natural process of expending more calories to offset the gain in muscle.

Predicted performance at different weights

Predicted VO2 Max: 37.9 ml/kg/min

Weight (lbs) Predicted time Time difference
134 lbs 01:53:21 -02:53
135 lbs 01:54:05 -02:09
136 lbs 01:54:48 -01:26
137 lbs 01:55:31 -00:43
138 lbs 01:56:14
139 lbs 01:56:57 00:43
140 lbs 01:57:40 01:26
141 lbs 01:58:23 02:09
142 lbs 01:59:05 02:51


Finally, Cinnamon also suggests that you should keep an eye on what you eat, not just how much of it. Your body is now a well-oiled, running machine and it needs good fuel to make it go. I guess it’s time to upgrade from regular to premium gas because you’re straight-up turning into a Ferrari or, in my case, a pretty tricked out Honda.

Do you find that you gain weight when marathon training? Is it something you try to prevent or do you go with the flow?

9 Responses to “Weight, What? Gaining Weight During Marathon Training”

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  1. sally says:

    This was interesting for me, as I’ve recently been super frustrated with my weight – and I just happen to be training for my first marathon. My question is this: why are there so many stick skinny runners out there then? I feel like I’m training my normally fast metabolism to slow down, and this is no bueno. It’s almost enough to sour me on running. Do these extra few pounds fall off after the rac?

  2. Lemongrass says:

    @sally: yes, I’ve noticed that things balance themselves out at the end of the race but his is the most intense plan I’ve ever been on, having not trained for a full before so I’ll let you know on the other side of 26.2. I think many runners diet when they are not in the midst of an intense training plan. Or, and I’m sure others who do back to back training cycles could attest to this better, your body gets smarter about using its carbs and water. Just like the athletes who eventually can run with very little water or sugars, your body will figure out that this type of stress is normal and you should start accessing your fat stores more readily. I wrote this post a few weeks ago and I’ve already lost the three extra pounds I had “gained” so I’m back to normal. I’m not any lighter, but I think I’m smaller. Unfortunately, my cup size is the most dramatic drop in size. Oh well.

  3. After gaining weight when training for my first marathon I came up with a completely unscientific theory: our body’s ultimate job is survival and if it is working hard it will hold on to some extra pounds. I think that as someone who generally doesn’t carry much in extra weight, my body made sure to hold onto some of those calories while it was being put through training. I think that extra weight was there for survival reserves. Same thing happened when I was breast feeding. Sure the initial weight dropped quickly just as they said it would, but those last 5 lbs would not disappear until I was done breast feeding and the added “stress” of feeding another being (after just over 5 years straight of either being pregnant or nursing) was gone.
    Just my theory :)

    • Lemongrass says:

      Great theory. I had the same thing happen with bfing so I’m not surprised it’s happening again with marathon training!

  4. Grace says:

    Hmm, I definitely put on a few pounds while training for my last marathon. And I can pin that very specifically on ‘runger’ and strength training – while I was losing fat, I was building muscle. But as long as I’m a healthy weight, weight loss or gain has never been the end goal in and of itself – it’s a side effect of what I’m doing to reach my performance goal. I’m quite happy to add muscle if it helps me run faster!

    What IS interesting to me is the difference in how my body feels, weight-wise and muscle-wise, between marathon training and triathlon training. Now that I’m putting all my time into tri training, my shoulders, back and core feel a lot more solid but still lean, if that makes any sense. Even my legs feel more solid, in a way. And I kind of like the way I feel – I just hope it translates into performance gains! (I’m still rungry and still doing strength work, of course, so the swimming and biking is the only major difference between a tri training cycle and a marathon training cycle.)

  5. Vanilla says:

    It all comes down to one simple equation: if calories in > calories expended, then weight gain will happen. It doesn’t matter if one is an endurance athlete or sedentary..it’s a simple equation. I think that we as endurance athletes tend to think we lose more calories when we workout, so we think we can eat more. (I am guilty of this)! Plus, as we become more efficient with our workouts, we don’t burn as many calories. Did you know that it’s very common for the cyclists in the Tour de France to gain weight during the race?! Sounds crazy, but those guys are so efficient with their cycling, their bodies don’t require as much energy to go at fast speeds. But then, they have big meals waiting for them when they finish. They really need to be careful.

    My husband lost over 5lbs while training for Ironman, while I remained at the same weight. I have put on a couple of pounds while training for marathons. I tend to go by how my clothes feel and not so much the number on the scale. We are all different and our bodies handle things differently.

  6. Salty Salty says:

    My philosophy: train and eat to perform and the rest will follow. If people marathon train so they will look like Shalane Flanagan they will never look like Shalane Flanagan because Shalane Flanagan sure as heck is not training to look like Shalane Flanagan, she’s training to perform her best on race day.

    The other thing is that I agree with vanilla that you should probably ditch the scale and go by how you feel and how your clothes fit. As a marathon newbie your body is going through a transformation process which might involve learning to store more glycogen (water weight) or building more muscle mass. I’d ditch the scale and focus on getting your body ready to rock the race and trust that the rest will follow!

    Oh, and wean off those gels. You know you can handle them so wean off of them now so they will actually give you a boast on race day ;) That also might have the added benefit of helping you lean out a little bit.

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