Gaining Weight During Training?

News and Updates

by Jenna-Caer Seefried

Have you ever gained weight during a triathlon or marathon build? It has to be one of the most frustrating situations: you’re training down the house, putting in endless miles, dealing with sore muscles — and still the scale goes up.

There are a few reasons why this happens and, spoiler alert: you probably haven’t gained 20lbs of muscle.  (I’m guilty of telling myself it must be muscle gain.)

I’m sure a few of these points will be no-brainers and you’ve heard them a few times before.

Muscle and Fluid

First of all, the body’s own responses to training can cause weight gain through:

DOMS (Delayed Onset Muscle Soreness) – After particularity hard workouts in the short term your weight will go up as your muscles become swollen with fluid and stiff as they try to repair. This can also be true the first two weeks of a new workout program. If this is the case it won’t stick around and as your body recovers weight will go back to normal.

Legitimate muscle gain – OK, a lot of us will believe this is the reason we are gaining weight or justify it. Yes there is some muscle gain with endurance training but if your scale has gone up 20lbs while doing endurance training, it’s unlikely it’s all muscle mass.

Putting on extra inches even with all the training? We feel you. (Photo by Siora Photography on Unsplash)

Stress and Cortisol

However, a pretty major cause of weight gain during training is one that is often overlooked: the hormone cortisol.

Cortisol, also called the stress hormone, is a steroid hormone that helps the body metabolize glucose, control blood pressure, suppress immunity, and control inflammatory response. Involved in our “fight-or-flight” response, cortisol stimulates fat and carbohydrate metabolism as well as insulin release to maintain blood sugar levels, triggering a burst of energy and awareness that helps us respond to stressful situations.

Cortisol stimulates fat and carbohydrate metabolism for fast energy, and stimulates insulin release and maintenance of blood sugar levels. The end result of these actions can be an increase in appetite and can cause cravings for sweet, high-fat, and salty foods. With elevated cortisol levels, the body also produces less testosterone, leading to a decrease in muscle mass. With less testosterone to build muscle mass, your body starts to burn fewer calories.

Now, a small increase in cortisol is a good thing because it helps you crush workouts and stay focused. However if you continue to push your body with a tough training schedule and without proper recovery or fuelling, cortisol levels increase and start to work against you.

Yes, not eating enough or under-fuelling can be a cause of weight gain! If your energy needs are much higher than the calories you are eating, it puts your body into starvation mode and increases stress. It takes time and experimenting to find the balance between fuelling your body and over eating. However the easiest way is to eat whole foods to the point you are satisfied. I’m all about the 80/20 rule – 80% of the time real healthy foods, 20% time chocolate and whatever I’m craving.

Cortisol has an intricate relationship with the hormone insulin, which controls our blood sugar. Cortisol prevents insulin from converting blood sugar into fat (because it wants to keep the sugar in the bloodstream for ready use — fight-or-flight, right?). When this happens, the cells of our body can become resistant to insulin, causing the body to secrete more insulin. (High insulin levels are a precursor for diabetes.) This triggers cravings for sweet, high-fat, and salty foods.

High levels of cortisol are also associated with chronic insomnia and sleep disturbances. Poor sleep means poor recovery, which again triggers a stress response. It’s a disastrous feedback loop.

There are a few signs your cortisol levels are too high:

  • Disrupted sleep – are you waking up multiple times during the night? Or waking up early still tired and not able to get back to sleep?
  • Weight gain – Often around your face or abdomen while the rest of your body remains lean
  • Increased thirst and urination
  • Mood swings – well, this one may be hard to see the difference if you are in an Ironman training block (being hangry is no joke)

Bottom line: if your cortisol is too high from lack of recovery you are sleeping less, eating/craving more junk food and likely gaining weight as your body is under stress.

Stress and bad eating habits can cause unwanted weight gain even when you’re training down the house.

Bad Eating Habits

Know that it’s very common and easy to fall into some bad habits that cause weight gain even with hours of endurance training. Even for myself I’m usually the leanest I am in early season and then as I get closer to race day even I add on a few extra pounds with some bad habits.

These bad habits are:

Rewarding hard/long workouts with treats or huge meals – the ‘I earned this’ mentality. Treating yourself when you are active and working hard is not a bad thing, I’m all about balance (and chocolate intake) just don’t make it after EVERY workout – a 5km recovery run doesn’t mean you can eat all the cookies.

Using calories to try to overcome fatigue – I’m so guilty of this one. I’m tired I must need more carbs for this workout when in reality I’m just tired and all the carbs in the world won’t change that.

The best way to avoid weight gain during a big training block is to make sure you balance out the training with recovery, fuel well, and listen to your body when it needs rest.

Need help managing your weight? Get in touch with Jenna to discuss how she can help you.


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