Weight Gain During Marathon Training

Reasons Why You May Be Gaining Weight During Marathon Training

Why do I gain weight during marathon training?” is a question I get asked a lot. It is a great question, and one that many people wonder without actually asking. 

There are many reasons people gain weight during marathon (even half marathon) training. Many people start running or want to run solely to lose weight. While that is a great idea, and you certainly can lose weight, you can also gain weight. I don’t run to lose weight, I run because I love it. I rarely step on the scale because it’s just not important to me. I know I’m healthy because I eat right and exercise, therefore I don’t need a number to tell me what is healthy.

I am not against weighing yourself if you are trying to lose weight and want to keep track. I personally am not trying to lose weight, so weighing myself is not something I need to do. If you do like to weigh yourself, try to pick one day a week to do it, rather than daily. You fluctuate by a pound or two (or three) on a daily basis, so weighing yourself daily could be discouraging.

There is also a difference in what you wear while weighing yourself. My running shoes add one pound. Are you wearing a sweatshirt? I was wearing a sweatshirt and that also probably added some weight. Try to be consistent in weighing yourself. My suggestion: weigh yourself before you hop in the shower.

photo 1photo 2

Here are some reasons why people gain weight during training:

Misconception about caloric expenditure while running. Running one mile burns approximately 100 calories (at most). Many things can affect how many calories you actually burn such as weight, type of terrain, speed, and muscle mass. Burning 100 calories per mile is most likely at the top of end the expenditure, therefore you should not always assume you are burning 100 calories per mile.

Many people get in the mind set that since they ran several miles they can eat whatever they want. Junk food (candy, chips, soda, etc.) are high in calories and it does not take much to put those calories back in your system. There are approximately 250 calories in one Snickers bar, so if you ran 2.5 and eat just ONE candy bar you calorie expenditure would essentially be back at zero.

Eating more than you burned off. This is very similar to the above problem. Often times people will assume because they ran 10 miles they can treat themselves all day long. While 10 miles is a good distance, and approximately 1,000 calories- it is easy to eat 1,000 calories. You must be conscious of what you put back in your body. I would rather eat a plateful of sweet potatoes than one candy bar.

Your appetite increases. A LOT. When I marathon train I am CONSTANTLY hungry. It becomes really important to eat healthy snacks and meals throughout the day instead of filling up on “wasted” calories such as junk food. Typical snacks for me include fruits and nuts, banana bread, and raw veggies.

I actually track what I eat daily. I don’t do this for weight reasons, I do this to make sure I am consuming enough carbohydrates, fats, and protein in my diet.  Since I don’t eat meat I need to make sure I consume enough protein to prevent injury and help with muscle repairs. I use “My Fitness Pal” to track my daily caloric intake.

Impulsve. When I get back from a long run (15-20 miles) I am starving. It is really easy to pour some sugary cereal or grab something quick to relieve my hunger, but typically quick things are not always the best. Instead, pour a glass of milk to tide you over while you make something healthy whether that is an omelet, smoothie, or a bowl of oatmeal.

Muscle weighs more. Muscle weight more than fat, and you are going to put on more muscle mass while training whether it is through strength training or additional muscle mass in your legs. You must take this into consideration when getting on the scale.

Are you lazy the rest of the day? I am certainly guilty of this one. After a 20 mile run I just want to sit on my couch and do nothing. While that is certainly okay sometimes, you still need to be active throughout the day whether that is housework, taking an easy walk, or running errands.

Glycogen stores. Endurance athletes tend to have more glycogen stores in their muscle. This is a good thing, but it adds more water to your body, therefore adding weight.

Water. I drink a lot of water each day and that certainly adds weight. Runners need to consume water each day in order to stay hydrated throughout the day, as well as for the next run. Just be aware that it will add weight (and that is OKAY!)

I hope some of these reasons help you determine why you are gaining weight and give you some relief that it is normal to add some weight, just make sure you are adding healthy weight.

4 thoughts on “Weight Gain During Marathon Training

  1. Hi Courtney!

    I really liked this post! I found out I was not eating enough calories and carbs to maintain my weight from my nutritionist, so I started myfitnesspal too. As I train for my half marathon, I usually fluctuate up to five lbs throughout the week. Its crazy! Its just easier to focus on healthy eating rather than low weight.

    My long run/hard workout days make me ravenous either the day of or the next day. If you could go through a daily record of what you eat on a normal day and then maybe a long run day that would be useful! I am still learning how to properly feed myself and train, although it is my third half. I’m hungry all the time at odd times of the day (especially mornings), so lots of snacking is involved(: An example or template to go off of very much helps.


    • Hi Jordan!

      I am kind of obsessed with My Fitness Pal 🙂 I can certainly do a post about what I typically eat throughout the day so to give you some helpful ideas.

      I know what you mean about being hungry the day after a long run- those are the days I am most hungry. I seriously could eat all day long!


  2. Hi Courtney! Such a great topic! I’m 27 with 1 marathon under my belt and about to start training for my 2nd, so the weight fluctuation is something that really messes with me and I wondered if you have any tips for how to get MORE calories in the healthy foods during your marathon training. I’m completely guilty of the ravenous post-run thing you mention and notoriously end up shoving a burger and milkshake down my throat at the first signs of hunger during peak mileage. I really want to fuel my body better, but nuts and berries are just not enough! Neither are protein shakes and even though I love the way veggies make me feel, I just can’t get enough to feel full! What should I eat to get back what my body’s demanding? And is there any way to keep a more consistent intake of calories when you have to run SO much farther 1 day of the week (and thus need so much more food). I’m a small framed female, with a family history of osteoporosis, so I really want to make the best decisions for my body now, while it counts, and I know I’m at a greater risk for some things. I have a history of stress reactions in my shins, which I blame partially on my inexperience as a runner in trying to “tough out” shin splints, and possibly a poor diet, not replacing enough calories, which research shows can increase the propensity for shin splints. Soooooooooo I have to be super anal about getting enough calories to keep injuries away (and extra Calcium + vitamin D).

    Second question: I use my fitness pal, but when I look at my marathon training weeks, in the red/green bar graphs, my weeks are always are always “v-shaped”, meaning the calorie intake suddenly drops on the day of the long run (usually under because of what I’ve burned) and then slowly increases the further the day of the week from the long run. It’s almost as if my body takes a few days to get its appetite back. I drink protein shakes and try to get as much food as I can after the peak mileage, but it’s never really even. I try to think about weight gain/loss as a weekly game (as long as I “break even” by week-end, I’m healthy), but it’s sort of tough on my body to constantly have to recalibrate how much it’s going to have to eat that day! Basically, it gets used to something and on the days farthest from the long run, it screams “FEED ME NOW!” and the days closest to the long run, it is pretty much fasting unintentionally. Is there a way to manage calorie intake better on a daily basis, so my body & appetite don’t feel the shell shock so much? Is this “v-shaping” in my weekly caloric intake a bad thing? Or do all marathon runners sort of bounce up and down on a daily basis (depending on how much they run)?

    Suddenly my dreams of running regular marathons are starting to look more like joining the high school wrestling team…

    • I can relate to the feeling of constantly being hungry! One of the things I do in order to keep my hunger in check is to have A LOT of pre-made snacks and meals ready to go. I agree- as amazing as fruits, veggies, and nuts are, they do not always keep my feeling full. Usually after major runs I put more protein powder in my smoothies which helps a little bit with feeling more full.

      The day of a long run I usually have 2-3 “GU” energy gels throughout the race with electrolyte replacements in my water, and immediately following the run I have a large smoothie with protein powder. I make sure to drink that immediately following the run so help my body refuel, but to also satisfy my hunger quickly.

      Once I’ve had my protein smoothie I can stretch and think of a healthier option for lunch or breakfast.

      What type of protein are you eating? I do not like a lot of meat, but I do eat more during training because it makes me feel full for longer. Even if its putting grilled chicken or shrimp on a salad, it helps.

      In my classroom I have a mini fridge stocked with Chobani yogurt and individual string-cheese to snack on throughout the day.

      I try to eat breakfast before I leave my house, another quick breakfast (yogurt and fruit) around 9 when I have my planning period, a big lunch, and several snacks until dinner time, and then more snacking before bedtime. The key is to eat healthy foods and not fuel up on “wasted” calories (junk food, candy, etc).

      As for your second question- it makes complete sense to me! Yes I am hungry the day of along run, but typically I am MUCH hungrier the day after a long run. It is quite common to not be as hungry after running 15-20 miles, but rather be extremely hungry the next day. We just have to remember even though we don’t feel hungry we must take in calories the day of a long run.

      If I’m hungry I eat. I don’t ever not allow myself to eat, but I do look at what I am eating to make sure it is going to benefit my running.

      I hope this helps!

Leave a Reply

Your email address will not be published. Required fields are marked *