Written by Chrystal Moulton, Staff Writer. Individuals on a very low-calorie diet for weight-loss are three times more likely to develop gallstones. Those on the very low calorie diet lost 2.8 lbs in 3 months.
In a population cohort study, researchers sought to find the risk of symptomatic gallstone development (gallstones requiring hospital care) associated with very low calorie (500kcal/d) versus low calorie (1200-1500 kcal/d) diets. Participant information was taken from a company called Itrim in Sweden. Only participants within their database between January 1, 2006 to May 31, 2009 who registered for the very low calorie and low calorie diets were eligible for the analysis. The raw data from the company was then linked to the National Patient Register, Prescribed Drug Register, and Cause of Death Register of Sweden. Information linked to the nation registers allowed the researchers to find risks associated with participation in either of the diet plans.
Each of the weight loss programs lasted one year. The first 3 months of the program was called the initial weight loss phase followed by a 9 month weight maintenance phase. The very low calorie diet (VLCD) and low calorie diet (LCD) weight loss programs are as follows:
Table 1. Study Protocol
| Very low calorie diet (VLCD) | Low calorie diet (LCD) | |
| Weight loss phase (3months) | 500kcal/d for 6-10weeks (fluid diet)Gradual re-introduction of normal food for 2weeks | 1200-1500 kcal/d |
| Weight maintenance phase (9months) | Exercise 2-3times/week 30-45minActive transport to work (walking highly encouraged)Dietary adviceSelf-monitoringBehavioral changes | Exercise 2-3times/week 30-45minActive transport to work (walking highly encouraged)Dietary adviceSelf-monitoringBehavioral changes |
| Type of food | Liquid based formula diet | 2 calorie restricted normal meals & 2 formula diet meals |
Trained health coaches collected and recorded body weight, waist circumference, height, and body mass index (BMI) for each individual at baseline, 3, 6, and 12 months. Participants were placed into one of three categories based on BMI: underweight (<18.5), normal weight (18.5-24.9), overweight (25-29.9), and obese class I/II/III (30-34.9/ 35-39.9/ >40). Subjects from both weight loss diet groups were then matched in age, sex, BMI category, waist circumference and history of previous gallstones. In order to compare the risk of gallstones in the VLCD group, the LCD group was used as a control. Conditional risk in the LCD group was defined as 1.0, in this study, indicating no risk compared to the VLCD group. Assessment of risk was based on this relationship using hazard ratios, which determine the likelihood of symptomatic gallstones in the VLCD group compared to the LCD group.
After 1:1 matching of participants from both groups, researchers had a total of 6,640 participant records eligible for analysis (VLCD=3320 and LCD=3320). Data showed 19% of participants were identified as overweight, 51% as obese class I, 23% as obese class II, and 8% as obese class III. Average age of participants was 46 years with a mean BMI of 33.4. Both groups were balanced for disease history and prescription drug use. After 3 months, participants of the VLCD group lost 12.7kg while participants in the LCD group lost 7.9kg (p<0.001). By the end of the trial, weight loss was 11.1kg and 8.1kg in the VLCD and LCD groups, respectively (p<0.001). Researchers found that the participants in the VLCD group was three times more likely to develop symptomatic gallstones than matched individuals in the LCD group (gallstone occurrence: VLCD-48, LCD-14; hazard ratio (HR) = 3.4, p<0.001). Researchers also compared individuals who never had their gallbladder removed (cholecystectomy) (n=3159/group) and found that people in the VLCD group were three times more likely to have their gallbladder removed than those in the LCD group (HR= 3.2, p<0.001).
In the end, researchers found an increased risk of symptomatic gallstones requiring hospital care and gallbladder removal among the VLCD group compared to the LCD group after a 1 year. The authors cited this research as possibly the first large-scale study on the safety of weight loss programs. However, the lack of a randomized design and information on asymptomatic gallstones as well as in home and primary care for gallstones were not included. Since the participants paid for and selected their desired diet program, researchers felt the data could not be generalized over the population.
Although the research identified a significant effect of very low-calorie diets with real-time data, more research is needed to assess the occurrence of gallstones over the general population. Future testing should also determine if there were protective factors in the low calorie diet not in the VLCD diet.
Source: Johansson, Kari, et al. “Risk of symptomatic gallstones and cholecystectomy after a very-low-calorie diet or low-calorie diet in a commercial weight loss program: 1-year matched cohort study.” International journal of obesity 38.2 (2014): 279-284.
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Posted May 23, 2014.
Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
- Johansson K, et al. Risk of symptomatic gallstones and cholecystectomy after a very-low-calorie diet or low-calorie diet in a commercial weight loss program: 1-year matched cohort study. Int J Obes (Lond). 2014 Feb;38(2):279-84.
