“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.
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.