Will Reta decrease running performance?

[u/Traditional-Yam6959]

Hi, I’m a 20F looking to lose about 5 kg using retatrutide. I’m a long-distance runner and have completed multiple marathons, so running is a big part of my life, but I’m aiming to lean out slightly.

I took my first injection about a week ago and have already noticed a drop in my running performance, especially a slower pace. From what I understand, this can happen due to factors like increased heart rate, reduced calorie intake, and lower glycogen stores.

My question is whether this is just temporary while I’m on the medication, or if it could have longer-term effects. Once I stop retatrutide after a few months, is it likely that my performance will return to baseline or even improve, or could this dip in performance carry over?

Would really appreciate hearing from anyone with experience or insight on this.

[u/jimbeam001]

I am an ultra runner and recently ran a half marathon and actually had to take a break at around kilometre 12 due to the fact that my stomach felt really full almost too full and this usually happens because long distance running leads to the blood going to your legs instead of being in the stomach so that it just difficult to process any food that you intake. Without the GLP one it normally is not that easy to intake much food but now I found it is even way harder and the stomach really shuts down. On the other hand, I have found that running in the morning on water only if you’re doing a keto diet that the GLP one is really helpful because you burn your fat as an energy use anyway.

[u/Traditional-Yam6959 → u/jimbeam001]

Yes but isn’t it dangerous to do keto on Reta because of the possibility of ketoacidosis…

[u/Thee_PRIDE → u/Traditional-Yam6959]

Don’t fucking do keto on Reta. Fat is incredibly slow in digestion and with Reta already slowing your stomach down extensively, you will be able to eat much less than you normally would considering Reta already and turn into a slug. Low carb is ridiculous for a runner.

[u/gigantor21260 → u/Thee_PRIDE]

ultra runner Zack Bitter would disagree with you...

https://zachbitter.com/zach-bitter-low-carb

You clearly have NO experience with this and simply like to repeat nonsense you've heard as if it were factual information.

[u/Thee_PRIDE → u/gigantor21260]

Yes, I'm a sprinter? Of course my experience with low carbs is not going to be optimal?

[u/gigantor21260 → u/Traditional-Yam6959]

I've been keto/carnivore on and off for many years. I wondered about this issue, so I searched and searched before starting Reta. I was only able to find 2 examples of ketoacidosis connected to Reta. Both people were practically starving themselves, and both were terribly dehydrated. So... I've been keto/carnivore for the last 6 months on Reta, and it is working great for me.

I do think that if you are eating carbs, and so using mainly carbs for fuel, then Reta WILL certainly affect your running performance. You will be under fueling in a general sense, and if you are meeting your (high) protein goals, you are almost certainly eating too few carbs to ensure enough energy for you higher intensity runs or longer runs.

I think you could mitigate some of this by eating your daily carb allotment before your runs. Even on zero carb my body is able to refill my glycogen stores, although of course it takes longer than it does when I'm eating carbs, so... this route may mean longer times between runs.

I think as long as your caloric deficit is reasonable, and you are keeping yourself fully hydrated (both water and plenty of electrolytes) then you can feel good about experimenting with this.