Let’s discuss weight gain after your race. First, I’m not a doctor, just a certified endurance running coach, so please don’t bet your health on my comments below as I can’t see you and don’t know your medical history!
With that said, here is what my experience and training tell me about the weight gain after a long run or race (some experience this more than others): 1) it’s likely water retention which can be caused by a few different reasons (see below), and 2) do not go on a diet to get rid of the extra weight as it will likely go away on it’s own, and you need the proper diet in order to help your body repair itself after your long run/race in order to be better and stronger than before!
The water retention could be caused by being dehydrated (you didn’t drink enough during your race), and/or it could be your body retaining water to help it in it’s repair work, and it could also be made worse by overloading with carbs prior to race day. Carbs at the optimum time and in the proper quantity and quality are important for full marathoners for sure, but many half marathoners can store enough energy reserves via their normal healthy died to last their entire race. Half marathoners do not usually “hit the wall” for that reason. Teaching your body to use carbs more efficiently and to be able to store more are parts of a well designed training plan. If your’ training plan didn’t help you with that, you need a new one, or at least a knowledgeable advisor who can help guide you in that area.
BTW – The DOMS which many of you are also reporting is a good indication of the water retention being due in some part by the repair process which is underway in your body (DOMS = Delayed On-set Muscle Soreness).
One word of caution on eating post race. While you do need to eat well after your race to aid in your recovery, you should also make sure that you are adjusting the portions to fit your lower activity level, or the water retention weight will be replaced by fat storage.
In general, the water weight will go away over the next few days/weeks so don’t worry about that.
If you are sore for more than 3-4 days you should see a medical practitioner to ensure that you are not injured, but most times the DOMS will go away on it’s own (just think of your runners waddle as a badge of honor!).
Oh yes, stay hydrated! Some athletes think that since they have gained excess water weight they don’t need to drink anything. Wrong! Drink if you’re thirsty and make sure that your urine is a pale yellow color.
Your race didn’t end at the finish line, you are still dealing with it and these days can make a big difference in your recovery.
A good training plan will detail a post-race strategy as it’s very important to your recovery and future racing. If you don’t have one, please do some research on the internet, speak with a good sports medicine practitioner or ask here for advise.
I hope the above overview of this topic is helpful. There’s plenty of general info available on the internet. Since I’m not your coach (I don’t know any specifics about you from having worked together throughout your training), I can only provide general answers to general topics, but I’d be happy to help guide you with a general discussion of other running related topics, if that would be helpful to each of you.
I ask that you consider engaging with health care professionals (Nutritionist, Physical Therapist, Message Therapist, Sports Medicine Specialist, etc. as required to provide specific guidance). You are part of the small number of endurance athletes (many doctors don’t have much experience working with us as our numbers are relatively small – about 1% of the total population and an even smaller portion of that number for full marathoners).
I am in awe of what each of you have accomplished, and even after all these years, your stories, trials and tribulations amaze and humble me. You are my inspiration and I thank you for that! I mean everyone, from our race champions to the back of the pack athletes – if you are giving it your all and a bit more, you are a winner and I admire your accomplishments.
RRCA Certified Endurance Running Coach