Calcium May Literally Make You Poop Out Fat

I came across a study about something I find very interesting. A picture of Calcium in Faeces

It involves dietary Calcium and faecal fat excretion.

Faeces is dirty business, but someone has got to do it, and I am very grateful to those researchers.

I’d just like to take a moment and admire the types of scientists who are willing to spend their days weighing and measuring shit, for the sake of improved health for the rest of us.

Alright, let’s take a look at the study in question.

Meta Analysis of Randomized Controlled Trials

It was a meta-analysis, a research study that compiles data from several related studies, in this case 13 randomized controlled trials, which makes it quite reliable.

What the studies analyzed (no pun intended) was amount of dietary calcium, either from dairy or supplements, and the amount of fat excreted in the faeces (the scientific term for shit).

The researchers note that several studies have shown that a higher calcium intake is associated with lower body weight.

In the intestine, calcium is believed to form insoluble calcium soaps with fatty acids and bile acids, which may result in a decrease in the digestible energy (calories) in the diet.

To put it simply, a small amount of fat isn’t absorbed by the body but is instead flushed down the toilet, leading to a small part of the calories consumed not to be used for energy.

Calcium and Faecal Fat Excretion

It turned out that calcium, either from supplements or dairy products, can increase faecal fat excretion by 2-5.2 grams per day.

The long term significance of this is unknown, but 2-5.2 grams (18-47 calories) per day of fat do amount to about 1-2.2 kg (2.2-4.9 lb) in one year.

However, it is definitely possible that the regulatory mechanism in the brain will account for the lost energy by increasing food intake.

A drug called Orlistat operates in a similar but more effective way, by reducing the amount of digested and absorbed fat in the diet.

So you might consider Calcium to be kind of a much weaker, but natural alternative to Orlistat, without the side effects, and some additional health benefits.


I don’t know about you, but I do find the idea of slightly reducing the calories in the diet this way to be pretty interesting.

It is not a very large effect, but may make a significant difference over the course of a few years, given that the brain won’t compensate with increased food intake, which is a possibility.

However, there are other studies that have shown calcium to be associated with reduced body weight, so it seems plausible that this may work in the long term.

About 800mg of calcium per day seems to be all that is needed for these results, and a higher intake didn’t have any additional effect.

In my opinion, a moderate daily dose of calcium may be an effective supplement to aid in long term weight loss, along with a lifestyle centered around healthy eating and exercise.


  1. There was a British programme on TV last week trying out all the different weight loss threories – and this was one they used as an experiment. Analysed a man’s poop after no dairy for a few days and again after eating a lot of dairy for the calcium. His poop did in fact contain a lot more fat, even though he was eating identical food (non fat dairy swapped the meat)

  2. Johnny Palmer says:

    Interesting stuff julianne thanks for complimenting this post!

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