Remember that episode of the Biggest Loser when Daris gained weight during marathon training and Jillian bit his head off? Runners worldwide gave Jillian the virtual finger, knowing that it’s in fact very common to pack on some pounds while training for the big “M.”
Daris ran his first marathon in an amazing 4:02!
I was reminded of this Friday night during a conversation with a friend who I am coaching towards her first marathon. She is about half-way into her 20 week training plan for the Marine Corps in October. I asked how training was going – she said she was plowing through with consistency and strength, and had remained injury free. She then added (while we stuffed guacamole and chips in our pie holes), “But, I’m totally shocked. I’ve gained like 7 pounds. I thought for sure I’d lose weight while training, and this sucks.”
Enough already. I decided I needed to get to the bottom of this weight gain conundrum. Seriously, if you burn on average 100 calories per mile (depending on age, weight, sex, etc.) and run about 30 miles per week, then technically you have 3,000 extra calories of eating to do just to maintain your weight. Right? Wrong.
- You're building more muscle mass, which is denser than fat. So while that may translate to an overall weight gain, your body fat percentage has decreased and you're more toned than you were before.
- Your body is learning to store carbohydrates as fuel (glycogen) for your long runs. Those glycogen stores are important to completing your long runs and marathon without "hitting the wall", but you may see a couple extra pounds on the scale on certain days. Your body also requires additional water to break down and store the glycogen, so that will also add extra weight.
- You may have been increasing your calorie intake. Running a lot should not be an invitation to eat gallons of ice cream and trays of Oreos. The basic principle for weight loss still applies: You must burn more calories than you consume. To lose a pound, you have to burn, through exercise or life functions, about 3600 calories.
- You are drinking too many calories. Just because you're training for a marathon doesn't mean that you need to constantly drink sugary sports drinks. While it's important that you replace electrolytes during your long runs, you don't need to constantly have a sports drink at your fingertips the rest of the time. Plain water is fine for staying hydrated during the week.
Keep in mind too that if you go for a long run and then come home and sleep the rest of the day, you probably aren’t burning any more calories than if you were moderately active consistently for most of the day walking, hiking, cleaning the house, etc.
Also it’s important to eat enough food to keep you energized. Dieting while training for a marathon can be dangerous and lead to all sorts of issues like fatigue, illness, and injury. It is a slippery slope: If you eat more calories than you burn, you'll gain weight. If you eat too few calories, you won't have the energy to train.
Do you gain weight while training for races?
During high volume training I am ravenous and eat much more than I would normally. Even with lots of pooping, that usually this means a weight gain of 2-5 pounds at the peak of training. The extra pounds are mostly muscle and help fuel me towards a better race. After the race, my training volume decreases and I tend to naturally go back to my pre-training weight.
Is one of your motives to train for a marathon or half marathon weight loss?
For me, NO. I am happy with my weight. Yes, you read that right. I am probably in the minority on that one. I train for marathons to challenge myself and to be in the best physical shape I can be. Weight does not figure into the equation for me.
Stay tuned for for scientific info from Dr. San Millan (who did my performance testing) on why, despite your best efforts, you may not be losing weight during exercise.