Must... Force Down Food
September 21, 2016 11:27 PM   Subscribe

I'm never hungry after long runs. What gives?

I have always been into different types of workouts but I recently increased the intensity of my running. For whatever reason, I find that after my weekend long runs, it's very difficult to eat. In fact, the longer distance it is, the less I want to. I will force down something because I know it's terrible for one's body to not eat after such an intense workout, but why don' t I want to? This doesn't happen after other cardio workouts or when I do strength.

I'm more curious than anything. It's not causing any real problems for me, but I'm wondering: why is my body doing this?
posted by Enchanting Grasshopper to Health & Fitness (12 answers total)
Imma gonna guess adrenalin here? I had this effect when I was working as a chef, and still now during catering gigs I manage. Food is gross to me. Coworkers have even noticed and asked me about it! My appetite nopes far away when I'm physically and mentally active in a full body stress kinda way.

Just drink a high calorie tasty smoothie that's high protein/low sugar. You will be fine. Muscle recovery supplements are also great. Don't sweat it. Sometimes solid food is satan. You're normal.
posted by jbenben at 12:06 AM on September 22, 2016 [3 favorites]

I worked in a desert for years, and we were always taught that if you're dehydrated, you lose your appetite, because your body needs water to digest things properly. Anecdotally I've always found that to be true: if I'm dehydrated, I don't feel hungry and food is unappealing. But the same things start to look tasty after an hour or two of drinking water (not chugging it but just sipping it regularly).

So I would bet that you're dehydrated after your long runs and you haven't drunk enough water before you start trying to eat something. The difference between the long run and the weight room is you were probably getting something to drink periodically during your weight workouts, but there aren't drinking fountains available while you run.
posted by colfax at 12:09 AM on September 22, 2016 [3 favorites]

Seconding adrenaline. I don't run, but I do have severe anxiety and during a particularly anxious period in life I can go literally days without being able to eat more than a piece of toast or something. (I'm in such a time right now.) I don't even feel hungry and even something as minor as an advert for food on the radio makes me feel queasy and dizzy. The adrenaline thing makes sense - it's always during stressful times when I'm shaking and feeling nauseous. The rest of the time, I eat normally. It's great for losing weight!
posted by winterhill at 12:11 AM on September 22, 2016 [1 favorite]

Though the mechanisms are still being worked out, it's well recognized that exercise in general suppresses appetite temporarily, and that cardio in particular decreases appetite in more ways and for longer than resistance/strength training.

Relevant hunger hormones include leptin, ghrelin, and peptide YY. Cortisol may be involved but I believe the effect is indirect. As I understand it, the mechanism as it's been observed thus far is that for most people, all types of exercise reduce ghrelin (a key hormone that produces hunger in the short term). That explains the phenomena of hunger disappearing during a workout and then reappearing some time after. Cardio in particular also increases peptide YY (an appetite suppressant). So while the caloric deficit of running might make you more hungry over a broad time window, many people find it hard to eat right away.

I find that strength training inhibits hunger while I'm doing it, then roars back with a vengeance shortly after I'm done. High intensity cardio usually makes me less hungry or even unable to eat for hours, but I remain quite thirsty. Lower intensity cardio has less of an effect.
posted by daveliepmann at 12:41 AM on September 22, 2016 [6 favorites]

I think there may also be a part where your body has burned through the carbohydrate fuel you had in your stores and is fully in fat burning mode. Even lean people have enough fat to fuel the body for quite some time.

The lack of hunger is a very common, and often surprising, aspect of keto or low carb/high fat diets. In this case people are choosing their foods to ensure that their metabolism a remains tipped over into fat burning mode, by just not taking in the other fuel source (which, by its metabolic process, promotes storing fat rather than using it as fuel.)

Do you get thirsty? If you crave water but just aren't hungry at all, that may also be a clue that you're just burning fat.

I say, if it's not affecting you in a negative way, trust your body.
posted by Sublimity at 2:48 AM on September 22, 2016 [1 favorite]

I've experienced this too. Sometimes it's due to queasiness. I always assumed that your blood was still being distributed to your extremities after a long run. Blood moves to the stomach to aid digestion. Maybe it's just not there yet? But yes, sure enough, hunger usually comes in time.
posted by Borborygmus at 4:21 AM on September 22, 2016

I would also guess dehydration. I'm one of those "hungry all the time." kind of people, but there are two situtations where I have no appetite. The first is when I'm dehydrated (I.E. I drink 1.5 litres while running, then drink 5 litres of water over the next four hours and I still don't have to pee). The second, I haven't nailed down what causes this, but it's when I get the post-run shivers/chills.

As the thing that I've found ends the post run chills for me fastest is drinking 0.5-1 liter of water that's as warm as I can still drink it comfortably (warm shower and cuddling up with warm clothes and a heating pad don't seem to do much), this implies that there's at least minor dehydration involved.

I'd advise 1) trying to work more on hydration on your long run (do shorter loops so you can replenish water bottles, or get a hydration pack), and 2) if you're not hungry when you first get back, drink 0.5-1 litre of water immediately (in whatever temperature you want), and see how your appetite is in 20-30 minutes.

Additionally, are your runs long enough that you should be taking in calories during the run? If so, are you taking in calories?
posted by nobeagle at 6:01 AM on September 22, 2016 [1 favorite]

I have this same experience. The more intense my run is, the less I want to eat afterwards for an hour or two. If you still eat enough over the entire day, I wouldn't stress out about it unduly. I'm thirsty, so I try to consume sports drinks immediately afterwards, so I don't think dehydration or starvation is a concern. Normally I can more than make up for it a couple hours later.
posted by Lame_username at 6:23 AM on September 22, 2016

I'm never hungry after long runs. I just hang out until I am hungry.
posted by roomthreeseventeen at 7:01 AM on September 22, 2016 [1 favorite]

consider chocolate milk!
posted by changeling at 8:55 AM on September 22, 2016

It's really common, but I don't think it's terribly well understood. It used to hit me pretty hard after longer training runs and even some shorter races; my friends and I used to describe it as our digestive systems shutting down temporarily to prioritize the run and taking a while to restart.

A quick search turned up an article mentioning some of the possible causes (caveat: written by a graduate journalism student):

-extended diversion of blood flow from the digestive system
-stress response to tissue breakdown
-changes to hormones regulating appetite (increase in those related to fullness, decrease in those related to hunger)

The last item feels a little like hand-waving tautology - exercise makes you less hungry because it influences hormones that control hunger - but at least it points to a mechanism.

Thinking of it as an inelastic response to recruiting blood flow and other resources explains why I don't think I had any similar reactions to other types of cardio or to strength training, which were either much less intense in effort/duration (demands on overall blood flow and resources were lower) or had recovery breaks built in (intense demand for resources, but with time between efforts for everything to mostly return to normal).

I think I also remember a reference to it in Timothy Noakes' excellent Lore of Running (somewhat dated, as the 4th edition was published in 2001), in the context of nausea from overhydration, since only so much liquid can be absorbed per hour during a workout or race, and unabsorbed fluid can lead to varying degrees of nausea and a lack of appetite, but can't dig out my copy for an exact reference right now.

My (very complicated) strategy was usually to get a little food and liquid in my system right away and then eat normally when my appetite returned.
posted by verschollen at 3:34 PM on September 22, 2016

I've noticed the same thing. I'm currently marathon training and I haven't been able to eat dinner on days that I run. I've been eating bigger lunches to compensate. I run after work, which gives me enough time to digest lunch. Soon I'll need to start running in the mornings, as sunset comes earlier and earlier. I don't know what I'll do then. Skip lunch and eat a big dinner, I guess.
posted by domo at 10:03 AM on September 23, 2016

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