How To Avoid Marathon Weight Gain

The rumored weight gain is so fear-inducing that many people avoid signing up for a marathon just because of it.

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We’ve all heard of the “freshman 15,” the extra weight so many kids seem to mysteriously pack on during their first year of college. Truth be told it’s no mystery: It’s cafeteria food, late-night pizza deliveries, and all of the beer they probably aren’t allowed to be (legally) drinking yet.

But I digress.

In the running community, many of us have also heard of the mysterious marathon weight gain, the phenomenon where runners training to complete a 26.2 mile race pack on a few…or sometimes even a little more than a few…pounds during their training cycle. The rumored weight gain is so fear-inducing that many people avoid signing up for a marathon because of it. A number of my clients who have worked hard to achieve weight loss tell me they would like to train for a marathon but are scared they will gain back some of the weight they lost. Their fear is valid.

It seems almost counterproductive to train so hard and run hundreds of miles over the course of many months only to end up gaining weight. So what exactly is going on here? And are you doomed to gain the marathon training weight?

Let me explain.

Weight loss, at its very core, is a very simple concept. Burn more calories each day than you consume. A net loss of 3,500 calories is the equivalent of burning off one pound of excess body fat. Weight gain is the exact opposite: Consume more calories than you burn, and your body will convert and store those extra calories as fat instead of burning them as fuel.

So if we are burning all of these calories training for a marathon, where does the weight gain come in?

As a long-distance runner of nearly 10 years, I’m going to let you in on a not-so-secret fact: Running makes you hungry. Really, really, hungry–as it should. Your body works hard to cover those miles. But something else happens when you start covering much longer distances in your training runs: The hunger leads you to believe you earned pretty much anything in the food world, calories be damned.

For example, “I just ran 20 miles before most people even got out of bed this Saturday morning. This accomplishment most certainly deserves _____” (fill in the blank here: three donuts, a huge plate of bacon, an extra-large frosty iced coffee, a juicy cheeseburger and a pint of beer…or three. You get the idea.) Before you know it, you’ve very quickly and almost effortlessly eaten back all of the calories you burned during that run and then some, leading to a net increase in calories and the resultant weight gain.

To further add to this dilemma, running long distances can–and will–make you tired and sore. Sure, you may have burned 1,800 calories during your long training run, but then you sat on the couch recovering for the rest of the day, getting in very little other activity and not burning any extra calories. At the end of the day you may have burned no more (or maybe even fewer) calories than you burn on an average day, despite your long training run.

So how do you avoid this trap?

1. Be realistic with your caloric expenditure. Running typically burns 100+/- calories per mile, but this can vary greatly depending on age, weight, gender, fitness level, and a number of other factors. If your goal is weight loss, assume you are on the lower end of the calorie burn. Be sure to account for any calories you may have taken in during training (such as carbohydrate gels, sports drinks, etc.) Also factor in the lack of calorie burn if you spend the rest of the day relaxing (not that anyone blames you for resting!)

2. Refuel quickly post run. Getting in a healthy snack immediately after your long run will help you avoid what I call the “runchies”…when you become absolutely ravenous post long run. Refueling your body immediately will help you avoid the urge to eat absolutely everything on the menu or in your refrigerator.

3. Refuel wisely. Everyone loves a nice cold beer or fried bar food from time to time, but don’t make these post-run treats a habit. Avoid the “I earned this” mentality. Instead, refuel with fresh, whole foods that are more nutritionally dense. These foods will not only keep you satisfied and feeling full with fewer calories but also replenish your body and the nutrients lost during your training.

One thing to keep in mind: Not all marathon weight gain is bad. If you are a new runner, chances are you will be building muscle and storing extra water and glycogen (fuel) in your muscles. All of this can lead to a higher number on the scale.

So in conclusion, no, you are not necessarily doomed to the marathon training weight gain, as long as you keep your calories in check and those runchies at bay. Most of all, do not let the fear of potential weight gain keep you from signing up for a marathon. Crossing that finish line after months of hard training is an amazing accomplishment that you will not regret!