Gallbladder in pink
Do gallstones improve or worsen on a low carb / high fat diet? It’s a common question with an interesting answer.
The gallbladder stores bile, a yellow-green fluid manufactured in the liver. The bile is used to digest the fat you eat. The question is: Is it good or bad for the gall bladder to eat fat?
The conventional fat phobic answer
The usual medical belief today is that eating fatty foods can result in gall stones. This is because what happens if you already have gallstones in the gallbladder and eat fat: A gallstone can get stuck on the way to the intestines and give you a gallstone attack (pain in the top right part of your stomach).
The conventional advice is thus to eat low fat – and take pain killers if you get a gallstone attack. If the attacks continue the gallbladder is removed by surgery and the problem usually goes away. Probably with the side effect of slightly decreased ability to absorb fat and nutrients from what you eat (there is a reason we have gallbladders).
The conventional low fat advice rarely makes gallstone disease go away. Instead it often gets worse with time, until surgery is necessary. That is hardly a coincidence.
How to get gallstones
If you eat low fat less bile is needed to digest your food. More bile thus stays in the gallbladder. Long enough, perhaps, for stones to form. It’s been shown that people who (instead of fat) eat more carbohydrates are at increased risk of gallstones.
It all sounds logical. And there is even better evidence. The risk of low fat diets have been tested at least three times:
Studies of extreme low fat diets
- In a study of 51 obese people using an extremely low fat low calorie diet (just one gram of fat a day!) the gallbladder was examined by ultrasound before the diet and after one and two months. After one month four of the 51 participants had developed new gallstones. After two months more than one in four (13 people) had new gallstones! This on an almost fat free diet. Three participants needed to have their gallbladder removed during the study.
- A similar study examined 19 people eating an extremely low fat low calorie diet over 16 weeks. At the ultrasound examination at the end of the study five people (again about one in four) had new gallstones.
- A third study compared an extremely low fat diet with a diet slightly higher in fat during 3 months. More than one in two (6 of 11 people) in the group eating extremely low fat developed new gallstones. Nobody in the group eating more fat did.
Conclusion: Avoiding fat increases your gallstone risk!
Could it be the carbs?
Instead of looking at fat as the primary cause of gallstones, perhaps we should look at carbs.
One observational study reported that eating more carbs correlated with an increased risk of gallstones. The authors reported the same trend for glycemic index and glycemic load.1
Based on this study, reducing the total amount of carbs and focusing on lower glycemic carbs appears to be a reasonable approach to lower the risk of future gallstones.
What happens if you do the opposite?
What if you were to do the opposite of the usual advice? Regularly eat food with fat in it? Then more bile will be used to digest the food. The bile ducts and the gallbladder will be flushed regularly. Theoretically, stones will not have time to form, and pre-existing stones might (if you are lucky) be flushed out into the small intestine.
The risk is that if you already have gallstones, you may get discomfort as you flush them out.
The question is: Do you want to think short-term (low fat) or long-term (higher fat) solution?
Does high fat food work?
It’s logical to think that food higher in fat can result in a gall bladder free from gallstones, and the science supports it. One randomized controlled trial compared a higher fat to a lower fat diet in obese subjects over the course of 6 months. 2 The Higher fat group had better gallbladder emptying and no stones developed, whereas over 50% of the low-fat group developed gallstones. This was despite weight loss in both groups.
This fits with clinical experience and anecdotal reports from those who have experienced their gallstone disease disappear on a LCHF diet. Sometimes at the expense of initial gallstone attacks though.
Gallstones and kidney stones
Let’s compare the advice we give patients with kidney stones to the advice for gallstones. We tell patients with kidney stones to drink a lot of fluid, increasing the production of urine, so that stones do not have time to develop. If you already have kidney stones this advice could give you a painful attack initially as you pass the stone. But doctors still advise this despite the short-term discomfort as it is the better longer term solution.
The reason we give the opposite advice when it comes to gallstones might be the misguided fear of fat. If we were afraid of water instead, patients with kidney stones might have been advised to avoid drinking to avoid kidney stone attacks. If they did not improve, would we surgically remove their kidneys?
What do you say?
Have you had gallbladder problems? Have you tested a LCHF diet? What happened?
Another common question is if you can eat LCHF if your gallbladder is already removed. The answer is that this seems to work fine.
Some people without a gallbladder might have to increase their intake of fat gradually to allow their body time to adapt. Otherwise the body might not have time to digest the fat which could result in loose fatty stools initially. However this rarely seems to be a problem.
International Journal of Obesity Realted Metabolic Disorders 1998: Gallbladder motility and gallstone formation in obese patients following very low calorie diets. Use it (fat) to lose it (well).[randomized trial; moderate evidence] ↩