When losing weight, is it normal to have loose stools?

March 26, 2007 3:04 PM

When losing weight, is it normal to have loose stools?

I have been losing weight rather rapidly, 30 pounds since February 21. I gave up processed sugar for Lent and I didn't ever realize how much I was eating!

During this period of rapid weight loss, I have noticed that the majority of the time I use the bathroom, my stools are very loose. Not quite liquidy like diarrhea but close.

My question is - is this normal when losing weight? If not, I will run out and make an appointment with my physician immediately, but I'd rather not spend two hours of my time in transit and at the doctor's office just to be told it's normal. So, what are your experiences? Did you have loose stools when you lost weight?

Here are additional details: late 20's, female, started at 250 lbs, now 219 lbs, 5'5", U.S. resident, no recent travel, has not changed diet other than to cut out processed sugar (which includes corn syrup, white sugar, etc. - all sweeteners - but not natural sugar such as found in fruits and vegetables and not complex carbohydrates). If you have additional questions, email me at [e-mail]

posted by anonymous to health & fitness (19 comments total)

You don't mention exercising, but strenuous exercise has been known to keep everything, um, moving along. Google "runner's trots" if you want to know more.
posted by scratch at 3:24 PM on March 26, 2007

I'm not a doctor, and I'm not saying that it is 100% normal, but I did experience this myself. It wasn't the weight loss for me (as I didn't lose weight) but the diet change.

I strictly cut out all dairy, soy, eggs, wheat, fish, & nuts, so I was eating mostly produce, poultry, and rice. I would bet that cutting out processed sugar has caused you to eat far more vegetables & fruit than you usually do. They have much more fiber and water. I had fairly loose stools the whole time I ate that way.
posted by peep at 3:29 PM on March 26, 2007

First of all, congratulations on your weight loss. I know it is difficult! I'm currently on Weight Watchers and have lost 13 pounds so far.

I have noticed my own stools being a bit more loose than usual, but not anywhere close to diarrhea. I would guess that the changes in your stool are related to your weight loss (which is rather rapid, but not too fast, in my opinion).

If it would make you feel better, I'd make an appointment just to discuss it with your doc.
posted by susiepie at 3:30 PM on March 26, 2007

People who eat more fiber often have looser stools. If you've replaced the sugary stuff in your diet with veggies this may be why.
posted by selfmedicating at 3:43 PM on March 26, 2007

Oh, and mannitol (often found in sugar free products) is a laxative.
posted by selfmedicating at 3:47 PM on March 26, 2007

Not saying it's the same thing, but I dropped a bunch of weight by cutting calories, increasing fruit and veggie intake and exercising. Experienced the same thing which got progressively worse until it was finally diagnosed as Crohn's disease.
posted by plinth at 3:51 PM on March 26, 2007

(IANAD) Yep, I could tell when I was actually losing flab because my stool was loose. This coincided with an increase in dietary fiber, but ... it was a dramatic difference in both color and consistency than when I'm at my maintenance weight and not working out as hard.
posted by SpecialK at 3:52 PM on March 26, 2007

What you're experiencing is most likely due to the dietary change you've made, not the weight loss itself.

You don't mention if you're using sugar substitutes, but some of them, such as Xylitol, can have a laxative effect.

I'm also seconding selfmedicating's suggestion. There could be a number of components to this - You may be substituting fruits and veggies for the sugary snacks, which would result in more fiber. You may be drinking beverages that are hydrating you more since you've given up the sweets. If you're substituting more fats in your diet to make up for lost flavor then this could also get things moving.

You say that you've made no changes to your diet other than skipping the sugar, but that's a huge change! And congratulations on the weight loss.
posted by lekvar at 4:30 PM on March 26, 2007

I second everything that's been said here. Chalk it up to the change in diet. When I started losing a significant amount of weight two years ago, it took about two weeks for my digestive tract to adjust. If it's been going on for a month now, it might be time to visit a doctor and get things checked out, just in case.
posted by donajo at 4:42 PM on March 26, 2007

Wait, you've lost 30 pounds in a month?? That's not fat burning; you're dehydrated, and diarrhea or similar is a common symptom of being dehydrated. Start drinking lots of water, stat.

I would say it is not normal, no. I've lost 30 pounds in the last six months; I haven't had that problem.
posted by raf at 4:48 PM on March 26, 2007

While it's normal to have a change in your bowel movements when you change your diet/exercise, however, losing 30 lbs in approximately 1 month is a warning sign to me. Unless you are *very* overweight, male, and on a very restricted calorie diet, that's very VERY fast. That's a pound a day on average.

So, I would go to the doctor and mention this very rapid weight loss along with the loose stools. It's worth getting checked out to make sure that it's not related to a parasite or infection or something else you should get treated for.
posted by tastybrains at 4:50 PM on March 26, 2007

If you call the nurse at your doc's office, s/he can probably tell you when diarrhea is worth a doctor visit, and when it's just inconvenient. That would be a lot easier than making an unnecessary appointment.
posted by selfmedicating at 4:50 PM on March 26, 2007

I just started Weight Watchers about two weeks ago (almost three, actually) and I'm noticing a bit of the same thing. However, I'd like to join the couple of folks pointing out that losing a pound a day probably isn't healthy, so it'd be a good idea to ask a doctor.

Also, I can't resist...

MetaFilter: A dramatic difference in both color and consistency.
posted by CrayDrygu at 4:56 PM on March 26, 2007

Whoa, that's what I get for skimming the question. That kind of weight loss is considered unhealthy.
posted by lekvar at 4:58 PM on March 26, 2007

I just read back over the OP's stats and it's totally an unhealthy rate. I started out slightly heavier than that (and am also female), and combined WW (calorie restriction) with also removing all added sugars from my diet. While I'm losing weight rapidly, rapidly to me means approximately 2 lb a week.

1 lb a day, with or without the runs, is a sign of serious illness.

Men tend to lose weight at a scary-fast level, but that kind of weight loss is ONLY normal in men, and usually only for the first few months of a weight loss routine.
posted by tastybrains at 6:18 PM on March 26, 2007

Sugarfree products can and will give you the runs but that much weight in a month deserves a doc visit, diarrhea or not.
posted by konolia at 7:19 PM on March 26, 2007

selfmedicating writes "People who eat more fiber often have looser stools. If you've replaced the sugary stuff in your diet with veggies this may be why."

I also experience looser stools from the increased proportion of fibre during periods of weight loss.

A pound a day is a deficiency of ~3500 calories per day. An office worker about your size will steady state around 1600-2000 calories, a person doing hard labour will consume about 7000 calories a day. So if you're stacking bales 10 hours a day you're probably fine. However the closer you are to office worker the more unhealthy your current loss is unless you're playing six hours of basketball¹ a day or something similar. A 1-2 lbs a _week_ or 500-1000 calories a day is a common upper goal limit.

[1] Calories burned above baseline for select activities: Walking : 300, Bicycling: 300, Aerobics: 400, Swimming: 400, Tennis: 500, Basketball: 500, Jogging: 700.
posted by Mitheral at 9:41 PM on March 26, 2007

Whatever you're doing to lose 30 pounds in a month is almost certainly unhealthy. That's probably causing all kinds of intestinal distress. Man, if I can lose a pound a week I'm very happy.
posted by Justinian at 12:03 AM on March 27, 2007

Whatever you're doing to lose more than a few pounds a month is putting serious stress on your body. To be safe, you should see your doctor or GP about your weight loss and your stool condition.
posted by Blazecock Pileon at 5:48 AM on March 27, 2007