Low Fat and Very Low Calorie Diets: Gallstones
When I began researching the risks of very low calorie and low fat diets, I was surprised at just how common gallstones really are, because of this I thought this should be discussed first.
It has been well documented that weight loss, in particular, rapid weight loss increases your chances of developing new gallstones. In more then one study, it has been shown that new gallstones have formed in as little as only 4 weeks into a VLCD (< 800 cal) [1]. One study claims 25-35% of people who experience rapid weight loss form gallstones after their VLCD diet [2] and another that claims a higher percentage of 54.5% of subjects developing gallstones [3], not very good odds!
The reason this is thought to happen is because, during rapid weight loss, cholesterol concentrations in the bladder increases (keep in mind this is said to have nothing to do with dietary cholesterol). To top this off, when you eat very low fat and/or skip meals you do not stimulate your gall bladder to empty itself as often, which worsens the situation, allowing gallstones to form [4]. In fact, one study found a doubling of incidence of hospitalization for gallstones amongst women who fasted overnight for more than 14 hours, compared with women who fasted for 8 or fewer hours [5].
Gallstones are not just associated with VLC diets. A study was done to see if this also happens on a LCD (low calorie diet). Calories were approximately 925 calories a day spread across 4 liquid meals and one solid meal. By 17 weeks into the study, Six of the 47 patients (12.8%) displayed gallstones with 5 being asymptomatic (no symptoms). The sixth however, had severe pain and required a cholecystectomy at 30 weeks from the beginning of the study. [6].
Another study showed an increase risk of symptomatic gallstones with weight cycling, weight cycling is where people intentionally lose weight through diet but then later regain some or all of it back, rinse and repeat, this is otherwise known as yo-yo dieting. They found that weight cycling of more than 10 lb of weight loss and regain led to a 31% to 68% increase in the risk for cholecystectomy [7].
To add to all this, obesity itself is a pretty big risk factor for gallstones [8] with many already having silent gallstones (unsymptomatic), in which symptoms may be triggered when doing a VLCD [9]. Other risk factors are diabetes, metabolic syndrome, some medications including oral contraceptives or postmenopausal hormone replacement therapy (estrogen) [10] as well as females having a higher risk for gall stones which is thought to be due to estrogen increasing cholesterol concentrations in the gall bladder [11]
I was just reading a book called Gallbladder and Biliary Tract Diseases by Nezam H. Afdhal in Google book search [12]. On page 370 under the heading Lowering of the rate of weight reduction, it said this:
"Several Prospective studies have examined the relationship between weight loss and gallstone formation in the placebo arm of randomized controlled trials designed to prevent gallstone formation during rapid weight loss. In the study by Yang et al, patients who lost more then 25% of their baseline bodyweight during a 16 week very low calorie rapid weight loss diet had an incidence of new gallstone formation more then twice that observed for patients with a lower rate of weight loss. In two other studies, the rate of new gallstone formation increased stepwise with the rate of weight loss. Gallstones developed in only 8% of patients who lost less then 10 lb per month. This increased to 31% in patients who lost 10 to 15 lb per month and 49% in patients who lost 15-20 lb per month. The relationship between rate of weight loss and gallstone formation appeared to be stronger in women then men. These data suggests that the risk of weight loss is limited to only 1 to 2 lb per week."
One study that I was reading suggested a minimum of 10g of fat with every meal to reduce risks [13] (Keep in mind when I mention that minimum, it is in the context of trying to prevent gallstones only, personally I do believe we need more fat then that for other nutritional reasons). I have also read another study that claims physical activity helps in the prevention of gallstones [14] and another stating that 34% of cases of symptomatic gallstone disease in men could be prevented by increasing exercise to 30 minutes of endurance-type training five times per week [15].
Now if you think "well this won't happen to me" think again. There is a low carb, low fat diet in Australia that is very popular. Over here, diets like Atkins aren't very popular at all ever since the Atkins craze slowed down a few years ago. But then you have the Tony Ferguson Diet which is advertised very heavily on TV and is available through a chain of chemists, their forum is very busy. This diet is not as bad as kimkins calorie wise (unless it was abused) but it can still fall into the VLCD category simply by limiting the veggies and fruit. It consists of a meal replacement for breakfast and lunch along with a fist sized portion of lean protein for dinner plus veggies/salad and fruit for snacks. The meal replacements are protein shakes or soups full of MSG. The shakes if memory serves me correct only contain around 2g of fat so as you can imagine gallstones seems to happen a lot or at least that's what I have been told by regulars on their forum. I was poking around on their forum the other day, after a member bought up an issue with gallstones happening a lot there on a thread we have going [The Tony Ferguson Diet]. Now go to their forum, url is http://forumDOTtonyfergusonDOTcom/Search1-1-1.aspx (replace the "DOT" with a ".") and do a search on gallstones and see how common they are. But check this out, this is a comment by one of their staff members on this issue which I found on their forum:
"If you are prone to gall stones, then any form of weight loss can bring them on. There really is no reason why you can't remain on the program with gallstones. Due to the fact is has such little fat content, then it should not trigger a gall stone attack."
Now if you looked at just some of the links on gallstones I have just provided, you would see just how crappy this response is. Kimmer isn't the only one whom appears to be dishing out misleading and inaccurate advice and unlike Kimmer this person I would assume, is a trained professional.
As you can see, the odds are not great, seriously it seems pretty essential that you participate in regular exercise, make sure to eat enough fat regularly to encourage gall bladder emptying and avoid rapid weight loss unless medically necessary and under medical supervision.
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