You’re running for endless hours preparing for a 26.2 mile journey. You step on the scale to see the result of all that calorie burning cardio only to find that you’ve gained weight. Say what?
Marathon training can actually cause weight gain and friends…I’m here to figure out why and stop it.

Can marathon training cause weight gain?
1. Gained Muscle Mass
I think most of you know this, but muscle is more dense than fat. Therefore as you gain strength in your legs from training, you’re going to gain weight. The upside is that muscle is a more compact tissue than fat, so you may shed inches while gaining pounds. Muscle is also more metabolically active than fat, so even at rest muscle tissue burns more calories.
*For me, I had pretty muscular legs to begin with. And if you’ve ever seen me in person then you know I have freakishly large hamstrings. If there was an award for this then I should be nominated. Personally, marathon training doesn’t affect my legs via muscular gains.
2. Overestimating and Overeating
I just ran 16 miles today, I deserve this <enter decadent food here> Does that sound familiar? I’m guilty here too guys. You may burn 1600 calories on a 16 mile run, but it’s not that cut and dry. Add in a 300 calorie breakfast, 200 calories of fuel during the run, 100 calories of sports drink, and 200 calories of banana and protein post run. You’ve just consumed about half of your calorie burn and you were right to do so. Your body needed thost fuels. However now when you sit down to your burger, fries, and beer(s), you are overeating and extra calories = weight gain.
3. Increased Hunger
Working out for hours will increase your hunger. That’s totally normal. If you’re hungry eat, however make sure it’s something nutritious instead of eating cheerios from the box (ahem, me). Try to fill up on higher fiber whole grains and vegetables and lean protein post run for a more filling effect.
4. Increased Glycogen Storage
This one is a little more scientific, however it’s the one that I’m dealing with right now. Running takes energy and leg muscles. When you eat carbohydrates they are stored as glycogen, which you can think of as your body’s energy reserve. More energy needed = more energy stored. Glycogen (carbs) also attract water when they’re stored. This leads to an increased number on the scale. You can think of the weight as stored energy for future use. The good news is that your legs are now loaded weapons ready for race day domination! The bad news is that your jeans are a weeeeeeee bit tighter.
5. Lack of Sleep
There are a slew of current scientific studies that link lack of sleep to weight gain. There are several reasons for the correlations. First, when you sleep less you are awake more hours and your body needs food for energy during those extra hours so you’re hungrier. Second (and this is what the studies have shown), when you are sleep deprived you are more inclined to make a poor food choice and reach for high carbohydrate foods. You are also more likely to eat higher amounts of carbs at night. Finally, when you are sleep deprived your body’s level of cortisol increase. Lack of sleep has many more negative consequences including…
- interference with the body’s ability to metabolize carbohydrates and high blood levels of glucose, which leads to higher insulin levels and greater body-fat storage.
- decrease in leptin levels, which causes the body to crave carbohydrates.
- reduction of levels of growth hormone–a protein that helps regulate the body’s proportions of fat and muscle.
Why am I talking about inadequate sleep with runners? We get up early.. REALLY early to run. I have between 2-3 4am wake up calls a week to run. This is something I’m actively working on hence this week’s solo tempo run. It was tougher running alone, but it earned me 2 extra hours of sleep.
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