Why am I gaining weight while training for a Triathlon or Marathon?

It has to be one of the most frustrating situations, you’re in the thick of triathlon or marathon training, putting in endless training volume, dealing with sore muscles, and still the scale goes up. 

Spoiler alert – you probably haven’t gained 20lbs of muscle. (I’m guilty of telling myself it must be muscle gain)

1) Cortisol – A small increase in cortisol is a good thing, it helps you crush workouts and stay focussed. However if you continue to push your body with a tough training schedule and without proper recovery, cortisol increases and starts to work against you.

Cortisol has an intricate relationship with the hormone insulin, which controls our blood sugar. When cortisol levels increase, the cells of our body can become resistant to insulin. In turn, this may lead to an increase in blood sugar, weight gain, mood swings, food cravings and disrupted sleep.

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.

There are a few signs your cortisol is 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.

2) 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. Endurance athletes do need to fuel thier body to make sure you have the glycogen stores and calories for training sessions like those long runs.

3) 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.

4) DOMS -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 2 weeks of a new workout program. If this is the case it wont stick around and as your body weight will go back to normal as you recover.

5) Under fuelling. This goes back to the cortisol, if your energy needs are much higher than the calories you are eating it puts your body into a starvation mode. Your body is under stress, it can disrupt your sleep, increase cortisol and make it very difficult to not only train but recover as well. 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. 

6) 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.

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.  

If you do have weight loss goals to improve your body composition strength and resistance training is a fantastic way to build lean muscle and burn fat. Did you know muscle burns more calories at rest than fat does? It will also help to improve your form, strength and speed while reducing the risk of injuries. Check out Endurance Fit App and the Activation & Core is a great strength training program with 20 minute sessions that can help improve body composition and set you up for a great race day and season.

Right now you can get 6 months of access to ALL of the Programs on Endurance Fit for $75 – less than the cost of 1 personal training session.