It's been reported that as many as 90 per cent of people who lose weight end up gaining it back within a few years, a pattern that could increase the risk of gallbladder disease. According to a new study from the University of Kentucky Medical Center in Lexington, weight cycling - the pattern of losing and regaining weight - can nearly double a man's risk of developing gallstones later in life.
By the age of 60, up to 10 per cent Canadian men and 20 per cent of women have gallstones - deposits of solid material that form in the gallbladder. While many people have "silent" stones that don't cause any symptoms, others experience gallbladder attacks that can cause abdominal pain, nausea, vomiting, bloating, belching and gas.
The study, published last week in the Archives of Internal Medicine, analyzed data from 24,729 men, 40 to 75 years of age, who were part of the ongoing Health Professionals Follow-Up Study. The men provided information on body weight and intentional weight-loss episodes between 1988 and 1992 and were followed for symptomatic gallstones until 2002.
Weight-cyclers were more likely to have gallstones than weight-maintainers, men who stayed within five pounds of their initial weight. The more a man's body weight strayed from his initial weight, the greater his risk for gallstones.
Compared to weight-maintainers, light cyclers (men who lost between five and nine pounds per weight-loss attempt) were 21-per-cent more likely to develop gallstones. Moderate weight-cyclers (weight loss between 10 and 19 pounds) experienced a 38-per-cent higher risk. And severe weight-cyclers (weight loss of 20 pounds per attempt or more) had a 76-per-cent greater chance of developing gallstones.
More frequent weight swings also upped the risk of gallstones. Men who had two or more weight loss and gain cycles of more than 20 pounds were nearly twice as likely to develop gallstone disease compared to men who held their weight relatively constant during the study. Men who reported at least one weight cycle of 10 to 19 pounds were 50-per-cent more likely to have gallstones.
When the researchers adjusted for body mass index, a known risk factor for gallstones, the relationship held, suggesting that weight-cycling, rather than being overweight alone, influences the risk of gallstones.
Weight-cycling has also been linked to gallstones in women. A large study conducted among middle-aged women revealed that one or more cycles of losing and regaining 20 pounds or more was strongly related to gallbladder surgery.
Gallstones form in the gallbladder, a sac connected to the liver and intestine by a series of small ducts. After eating a meal, the gallbladder releases bile into the intestine, a substance that helps digest fat in food. Bile is made up of cholesterol, bile salts and other compounds.
Most gallstones are comprised of cholesterol. They can form when bile contains too much cholesterol or the gallbladder does not empty completely or often enough. When the gallbladder doesn't empty as it should, bile can become too concentrated and contribute to the formation of gallstones. (The amount of cholesterol in bile is not related to cholesterol in your bloodstream.)
Weight-cycling is thought to increase cholesterol in bile through its effect on body fat. Studies suggest that weight that is regained after a loss is mostly body fat. Higher levels of body fat, especially abdominal fat, can cause hormonal changes that may facilitate gallstone formation.
Factors that can increase the risk of gallstones include a family history of gallbladder disease, aging, and being female (women between 20 and 60 are more than twice as likely to have gallstones). Ethnicity also plays a role; according to the Canadian Liver Foundation, 70 to 80 per cent of the First Nations population has gallstones.
While you can't change some risk factors, the following strategies may help prevent gallstones.
-- Maintain a healthy weight: As body mass index increases, so does the risk of developing gallstones. Research also suggests carrying excess weight around your middle is linked to gallstones. A recent study of 42,000 women revealed that women with a waist of 32 inches or more were almost twice as likely to undergo gallstone surgery as those whose waist measured 26 inches or less. The findings are similar for men.
-- Lose weight gradually: Studies show that shedding weight too quickly (more than three pounds per week) increases the risk of gallstones in men and women. Rapid weight loss increases cholesterol in bile and promotes the formation of cholesterol stones.
Aim to lose weight at a rate of one to two pounds per week by following a well-balanced diet. Fasting, consuming too little fat, and skipping meals can decrease the gallbladder's contractions and prevent it from emptying completely.
-- Maintain your weight loss: By making permanent changes to your eating habits, you're more likely to prevent regaining lost weight. Research shows that keeping a food diary, eating breakfast, exercise, and weighing yourself on a regular basis are key factors to maintaining a weight loss.
-- Boost fibre: A number of studies suggest that eating more insoluble fibre from foods such as wheat bran, whole grains, fruits, vegetables, nuts and seeds offers protection from gallbladder disease. A high-fibre diet helps guard against gallstones by reducing the cholesterol content of bile.
-- Reduce refined sugars: Studies consistently reveal that a diet rich in refined sugars is associated with gallstones. Consuming too much sugar is thought to increase cholesterol in bile by increasing the secretion of insulin, the hormone that clears sugar from the blood. To cut back on refined sugar, limit soft drinks and sweetened fruit drinks. Snack on fruit rather than candy, cakes, cookies and pastries. Choose breakfast cereals with no more than eight grams of sugar per serving.
Get regular exercise: An earlier report from the Health Professionals Follow-Up Study determined that men who exercised at least 30 minutes per day, five times a week, were 20-per-cent less likely to develop symptomatic gallstones. A high level of physical activity may prevent gallstones by increasing bowel motility and reducing insulin levels.
Leslie Beck, a Toronto-based dietitian at the Medcan Clinic, is on CTV's Canada AM every Wednesday. Visit her website at lesliebeck.com.